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  • Polymer and Materials Science  (17,004)
  • Aircraft Propulsion and Power
  • 42.75
  • 1995-1999  (15,348)
  • 1950-1954  (2,047)
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  • 1
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    Application of Digital Particle Imaging Velocimetry to Turbomachinery (1999)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: Digital Particle Imaging Velocimetry (DPIV) is a powerful measurement technique, which can be used as an alternative or complementary approach to Laser Doppler Velocimetry (LDV) in a wide range of research applications. The instantaneous planar velocity measurements obtained with PIV make it an attractive technique for use in the study of the complex flow fields encountered in turbomachinery. Many of the same issues encountered in the application of LDV to rotating machinery apply in the application of PIV. Techniques for optical access, light sheet delivery, CCD camera technology and particulate seeding are discussed. Results from the successful application of the PIV technique to both the blade passage region of a transonic axial compressor and the diffuser region of a high speed centrifugal compressor are presented. Both instantaneous and time-averaged flow fields were obtained. The 95% confidence intervals for the time-averaged velocity estimates were also determined. Results from the use of PIV to study surge in a centrifugal compressor are discussed. In addition, combined correlation/particle tracking results yielding super-resolution velocity measurements are presented.
    Keywords: Aircraft Propulsion and Power
    Type: Planar Optical Measurement Methods for Gas Turbine Components; 2-1 - 2-33; RTO-EN-6
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  • 2
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    Comparison Analysis Between Nevada and TSS Using a Jet Engine Exhaust Nozzle Test Rig (1999)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: Thermal analysis in both simple and complex models can require calculating the propagation of radiant energy to and from multiple surfaces. This can be accomplished through simple estimation techniques or complex computationally intense computer modeling simulations. Currently there are a variety of computer analysis techniques used to simulate the propagation of radiant energy, each having advantages and disadvantages. The major objective of this effort was to compare two ray tracing radiation propagation analysis programs (NEVADA and TSS) Net Energy Verification and Determination Analyzer and Thermal Synthesizer System with experimental data. Results from a non-flowing, electrically heated test rig was used to verify the calculated radiant energy propagation from a nozzle geometry that represents an aircraft propulsion nozzle system. In general the programs produced comparable overall results, and results slightly higher then the experimental data. Upon inspection of individual radiation interchange factors, differences were evident and would have been magnified if a more radical model temperature profile was analyzed. Bidirectional reflectivity data (BRDF) was not used do to modeling limitations in TSS. For code comparison purposes, this nozzle geometry represents only one case for one set of analysis conditions. Since each computer code has advantages and disadvantages bases on scope, requirements, and desired accuracy, the usefulness of this single case study may be limiting.
    Keywords: Aircraft Propulsion and Power
    Type: Ninth Thermal and Fluids Analysis Workshop Proceedings; 49-67; NASA/CP-1999-208695
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  • 3
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    National Cycle Program (NCP) Common Analysis Tool for Aeropropulsion (1999)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: Through the NASA/Industry Cooperative Effort (NICE) agreement, NASA Lewis and industry partners are developing a new engine simulation, called the National Cycle Program (NCP), which is the initial framework of NPSS. NCP is the first phase toward achieving the goal of NPSS. This new software supports the aerothermodynamic system simulation process for the full life cycle of an engine. The National Cycle Program (NCP) was written following the Object Oriented Paradigm (C++, CORBA). The software development process used was also based on the Object Oriented paradigm. Software reviews, configuration management, test plans, requirements, design were all apart of the process used in developing NCP. Due to the many contributors to NCP, the stated software process was mandatory for building a common tool intended for use by so many organizations. The U.S. aircraft and airframe companies recognize NCP as the future industry standard for propulsion system modeling.
    Keywords: Aircraft Propulsion and Power
    Type: HPCCP/CAS Workshop Proceedings 1998; 177-181; NASA/CP-1999-208757
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  • 4
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    Simulation of Crack Propagation in Engine Rotating Components Under Variable Amplitude Loading (1999)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: The crack propagation life of tested specimens has been repeatedly shown to strongly depend on the loading history. Overloads and extended stress holds at temperature can either retard or accelerate the crack growth rate. Therefore, to accurately predict the crack propagation life of an actual component, it is essential to approximate the true loading history. In military rotorcraft engine applications, the loading profile (stress amplitudes, temperature, and number of excursions) can vary significantly depending on the type of mission flown. To accurately assess the durability of a fleet of engines, the crack propagation life distribution of a specific component should account for the variability in the missions performed (proportion of missions flown and sequence). In this report, analytical and experimental studies are described that calibrate/validate the crack propagation prediction capability for a disk alloy under variable amplitude loading. A crack closure based model was adopted to analytically predict the load interaction effects. Furthermore, a methodology has been developed to realistically simulate the actual mission mix loading on a fleet of engines over their lifetime. A sequence of missions is randomly selected and the number of repeats of each mission in the sequence is determined assuming a Poisson distributed random variable with a given mean occurrence rate. Multiple realizations of random mission histories are generated in this manner and are used to produce stress, temperature, and time points for fracture mechanics calculations. The result is a cumulative distribution of crack propagation lives for a given, life limiting, component location. This information can be used to determine a safe retirement life or inspection interval for the given location.
    Keywords: Aircraft Propulsion and Power
    Type: Design Principles and Methods for Aircraft Gas Turbine Engines; 38-1 - 38-8; RTO-MP-8
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  • 5
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    Simultaneous Active Source Control of Blade Row Interaction Generated Discrete Tones (1999)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: Unsteady blade row interactions in turbomachines generate discrete-frequency tones at blade pass frequency and its harmonics. Specific circumferential acoustic modes are generated. However, only certain of these modes propagate upstream and downstream to the far field, with these the discrete frequency noise received by an observer. This paper is directed at experimentally demonstrating the viability of active noise control utilizing active airfoils to generate propagating spatial modes that interact with and simultaneously cancel the upstream and downstream propagating acoustic modes. This is accomplished by means of fundamental experiments performed in the Purdue Annular Cascade Research Facility configured with 16 rotor blades and 18 stator vanes. At blade pass frequency, only the k(sub 0) = -2 spatial mode propagates. Significant simultaneous noise reductions are achieved for these upstream and downstream propagating spatial modes over a wide range of operating conditions.
    Keywords: Aircraft Propulsion and Power
    Type: Design Principles and Methods for Aircraft Gas Turbine Engines; 15-1 - 15-11; RTO-MP-8
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  • 6
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    Numerical Simulation of Multi-Stage Turbomachinery Flows (1999)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: A comprehensive assessment is made of the predictive capability of the average passage flow model as applied to multi-stage axial flow compressors. The average passage flow model describes the time average flow field within a typical passage of a blade row embedded in a multi-stage configuration. In this work data taken within a four and one-half stage large low speed compressor will be used to assess the weakness and strengths of the predictive capabilities of the average passage flow model. The low speed compressor blading is of modern design and employs stators with end-bends. Measurements were made with slow and high response instrumentation. The high response measurements revealed the velocity components of both the rotor and stator wakes. Based on the measured wake profiles it will be argued that blade boundary layer transition is playing an important role in setting compressor performance. A model which mimics the effects of blade boundary layer transition within the frame work of the average passage model will be presented. Simulations which incorporated this model showed a dramatic improvement in agreement with data.
    Keywords: Aircraft Propulsion and Power
    Type: Design Principles and Methods for Aircraft Gas Turbine Engines; 21-1 - 21-25; RTO-MP-8
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  • 7
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    Advanced Seal Technology Role in Meeting Next Generation Turbine Engine Goals (1999)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: Cycle studies have shown the benefits of increasing engine pressure ratios and cycle temperatures to decrease engine weight and improve performance in next generation turbine engines. Advanced seals have been identified as critical in meeting engine goals for specific fuel consumption, thrust-to-weight, emissions, durability and operating costs. NASA and the industry are identifying and developing engine and sealing technologies that will result in dramatic improvements and address the goals for engines entering service in the 2005-2007 time frame. This paper provides an overview of advanced seal technology requirements and highlights the results of a preliminary design effort to implement advanced seals into a regional aircraft turbine engine. This study examines in great detail the benefits of applying advanced seals in the high pressure turbine region of the engine. Low leakage film-riding seals can cut in half the estimated 4% cycle air currently used to purge the high pressure turbine cavities. These savings can be applied in one of several ways. Holding rotor inlet temperature (RIT) constant the engine specific fuel consumption can be reduced 0.9%, or thrust could be increased 2.5%, or mission fuel burn could be reduced 1.3%. Alternatively, RIT could be lowered 20 'F resulting in a 50% increase in turbine blade life reducing overall regional aircraft maintenance and fuel bum direct operating costs by nearly 1%. Thermal, structural, secondary-air systems, safety (seal failure and effect), and emissions analyses have shown the proposed design is feasible.
    Keywords: Aircraft Propulsion and Power
    Type: Design Principles and Methods for Aircraft Gas Turbine Engines; 11-1 - 11-13; RTO-MP-8
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  • 8
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    Coupled, Transient Simulations of the Interaction Between Power and Secondary Flowpaths in Gas Turbines (1999)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: This paper presents a coupled analysis of the interaction between mainpath and secondary flowpaths in gas turbines using transient simulations. Some of the topics include: 1) Need for Coupled Analysis; 2) Primary-Secondary Coupling Schematic; 3) Secondary Flow Requirement; 4) Objectives of Present Methodology; 5) Current Methodologies Recap; 6) Proposed Coupled Code Methodology; 7) Description of SCISEAL Code; 8) Description of Turbo Code; 9) Code Coupling/Interface Issues; and 10) Current Interface Strategy. This paper is presented in viewgraph form.
    Keywords: Aircraft Propulsion and Power
    Type: 1998 NASA Seal/Secondary Air System Workshop; Volume 1; 309-343; NASA/CP-1999-208916/VOL1
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  • 9
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    GAP Program Overview (1999)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: NASA's General Aviation Propulsion (GAP) program is a cooperative program between government and industry. NASA's strategic direction is described by the "Three Pillars" and their Objectives as set forth by NASA Administrator Daniel S. Goldin. NASA's Three Pillars are: 1) Global Civil Aviation, 2) Revolutionary Technology Leaps, and 3) Access To Space.
    Keywords: Aircraft Propulsion and Power
    Type: 1998 NASA Seal/Secondary Air System Workshop; Volume 1; 55-77; NASA/CP-1999-208916/VOL1
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  • 10
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    Damage Tolerance and Reliability of Turbine Engine Components (1999)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: A formal method is described to quantify structural damage tolerance and reliability in the presence of multitude of uncertainties in turbine engine components. The method is based at the materials behaviour level where primitive variables with their respective scatters are used to describe the behavior. Computational simulation is then used to propagate those uncertainties to the structural scale where damage tolerance and reliability are usually specified. Several sample cases are described to illustrate the effectiveness, versatility, and maturity of the method. Typical results from these methods demonstrate that the methods are mature and that they can be used for future strategic projections and planning to assure better, cheaper, faster, products for competitive advantages in world markets. These results also indicate that the methods are suitable for predicting remaining life in aging or deteriorating structures.
    Keywords: Aircraft Propulsion and Power
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  • 11
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    Assessment of Integrated Nozzle Performance (1999)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: This presentation highlights the activities that researchers at the NASA Lewis Research Center (LeRC) have been and will be involved in to assess integrated nozzle performance. Three different test activities are discussed. First, the results of the Propulsion Airframe Integration for High Speed Research 1 (PAIHSR1) study are presented. The PAIHSR1 experiment was conducted in the LeRC 9 ft x l5 ft wind tunnel from December 1991 to January 1992. Second, an overview of the proposed Mixer/ejector Inlet Distortion Study (MIDIS-E) is presented. The objective of MIDIS-E is to assess the effects of applying discrete disturbances to the ejector inlet flow on the acoustic and aero-performance of a mixer/ejector nozzle. Finally, an overview of the High-Lift Engine Aero-acoustic Technology (HEAT) test is presented. The HEAT test is a cooperative effort between the propulsion system and high-lift device research communities to assess wing/nozzle integration effects. The experiment is scheduled for FY94 in the NASA Ames Research Center (ARC) 40 ft x 80 ft Low Speed Wind Tunnel (LSWT).
    Keywords: Aircraft Propulsion and Power
    Type: First NASA/Industry High Speed Research Program Nozzle Symposium; 33-1 - 33-19; NASA/CP-1999-209423
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  • 12
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    PARC Analysis of the NASA/GE 2D NRA Mixer/Ejector Nozzle (1999)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Interest in developing a new generation supersonic transport has increased in the past several years. Current projections indicate this aircraft would cruise at approximately Mach 2.4, have a range of 5000 nautical miles and carry at least 250 passengers. A large market for such an aircraft will exist in the next century due to a predicted doubling of the demand for long range air transportation by the end of the century and the growing influence of the Pacific Rim nations. Such a proposed aircraft could more than halve the flying time from Los Angeles to Tokyo. However, before a new economically feasible supersonic transport can be built, many key technologies must be developed. Among these technologies is noise suppression. Propulsion systems for a supersonic transport using current technology would exceed acceptable noise levels. All new aircraft must satisfy FAR 36 Stage III noise regulations. The largest area of concern is the noise generated during takeoff. A concerted effort under NASA's High Speed Research (HSR) program has begun to address the problem of noise suppression. One of the most promising concepts being studied in the area of noise suppression is the mixer/ejector nozzle. This study analyzes a typical noise suppressing mixer ejector nozzle at take off conditions, using a Full Navier-Stokes (FNS) computational fluid dynamics (CFD) code.
    Keywords: Aircraft Propulsion and Power
    Type: First NASA/Industry High Speed Research Program Nozzle Symposium; 16-1 - 16-32; NASA/CP-1999-209423
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  • 13
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    Supersonic Jet Mixing Enhancement due to Natural and Induced Screech (1999)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Outline of presentation are: (1) Review of experimental apparatus. (2) Effect of natural screech of jet mixing; converging nozzle, underexpanded jet and converging-diverging nozzle, design pressure.(3) Effect of induced screech on jet mixing: produced by paddles in shear layers, similar to edge tones, and converging-diverging nozzle, design pressure. (4) Effect of paddles on near-field jet noise. and (5) Concluding remarks.
    Keywords: Aircraft Propulsion and Power
    Type: First NASA/Industry High Speed Research Program Nozzle Symposium; 9-1 - 9-15; NASA/CP-1999-209423
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  • 14
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    Application Focused Schlieren to Nozzle Ejector Flowfields (1999)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The motivation of the testing was to reduce noise generated by eddy Mach wave emission via enhanced mixing in the jet plume. This was to be accomplished through the use of an ejector shroud, which would bring in cooler ambient fluid to mix with the hotter jet flow. In addition, the contour of the mixer, with its chutes and lobes, would accentuate the merging of the outer and inner flows. The objective of the focused schlieren work was to characterize the mixing performance inside of the ejector. Using flow visualization allowed this to be accomplished in a non-intrusive manner.
    Keywords: Aircraft Propulsion and Power
    Type: First NASA/Industry High Speed Research Program Nozzle Symposium; 15-1 - 15-14; NASA/CP-1999-209423
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  • 15
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    PAR Analysis of HSR Nozzles (1999)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Only recently has computational fluid dynamics (CFD) been relied upon to predict the flow details of advanced nozzle concepts. Computer hardware technology and flow solving techniques are advancing rapidly and CFD is now being used to analyze such complex flows. Validation studies are needed to assess the accuracy, reliability, and cost of such CFD analyses. At NASA Lewis, the PARC2D/3D full Navier-Stokes (FNS) codes are being applied to HSR-type nozzles. This report presents the results of two such PARC FNS analyses. The first is an analysis of the Pratt and Whitney 2D mixer-ejector nozzle, conducted by Dr. Yunho Choi (formerly of Sverdrup Technology-NASA Lewis Group). The second is an analysis of NASA-Langley's axisymmetric single flow plug nozzle, conducted by the author.
    Keywords: Aircraft Propulsion and Power
    Type: First NASA/Industry High Speed Research Program Nozzle Symposium; 18-1 - 18-21; NASA/CP-1999-209423
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  • 16
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    Mixing Enhancement in Supersonic Jets by Delta-Tabs (1999)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The investigation includes carry out fundamental experiments studying mechanisms of effect: (1) experiments on subsonic and supersonic jets to assess influence of compressibility, (2) parametric study on tab geometry to optimize effect for given flow blockage (this effort led to "delta-tab"), (3) quantify mixing enhancement in the jet, and (4) analyze mechanism of streamwise vorticity generation.
    Keywords: Aircraft Propulsion and Power
    Type: First NASA/Industry High Speed Research Program Nozzle Symposium; 10-1 - 10-19; NASA/CP-1999-209423
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  • 17
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    Pratt & Whitney 2D Model in LeRC 9 ft x 15 ft Acoustics (1999)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The theory of mixer-ejectors for noise suppression is illustrated in this cartoon. Since jet noise SPL scales as velocity to the eighth power and diameter squared, increasing the jet diameter while lowering its velocity and keeping thrust constant decreases the noise. However, in supersonic craft, the drag penalty for increasing diameter at supersonic cruise makes this option very expensive. One would like to have a large engine during takeoff which could be shrunk during cruise. The retractable ejector is such an expandable engine. If the mixer flow can be expanded to the size of the ejector exit, the noise generated downstream of the ejector will be much less than the small diameter mixer nozzle alone. Of course, this also requires that the noise created in expanding the flow to fill the ejector be absorbed by a liner in the ejector walls so that none of this noise is heard. Since this mixing of internal hot gas and external cold air must take place in as short a distance as possible, the mixer must be very effective and therefore probably much noisier than a simple nozzle.
    Keywords: Aircraft Propulsion and Power
    Type: First NASA/Industry High Speed Research Program Nozzle Symposium; 7-1 - 7-21; NASA/CP-1999-209423
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  • 18
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    Thermodynamic Cycle Analysis of Magnetohydrodynamic-Bypass Airbreathing Hypersonic Engines (1999)
    In:  CASI
    Details
    Publication Date: 2013-08-29
    Description: Established analyses of conventional ramjet/scramjet performance characteristics indicate that a considerable decrease in efficiency can be expected at off-design flight conditions. This can be explained, in large part, by the deterioration of intake mass flow and limited inlet compression at low flight speeds and by the onset of thrust degradation effects associated with increased burner entry temperature at high flight speeds. In combination, these effects tend to impose lower and upper Mach number limits for practical flight. It has been noted, however, that Magnetohydrodynamic (MHD) energy management techniques represent a possible means for extending the flight Mach number envelope of conventional engines. By transferring enthalpy between different stages of the engine cycle, it appears that the onset of thrust degradation may be delayed to higher flight speeds. Obviously, the introduction of additional process inefficiencies is inevitable with this approach, but it is believed that these losses are more than compensated through optimization of the combustion process. The fundamental idea is to use MHD energy conversion processes to extract and bypass a portion of the intake kinetic energy around the burner. We refer to this general class of propulsion system as an MHD-bypass engine. In this paper, we quantitatively assess the performance potential and scientific feasibility of MHD-bypass airbreathing hypersonic engines using ideal gasdynamics and fundamental thermodynamic principles.
    Keywords: Aircraft Propulsion and Power
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  • 19
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    Effects of Hot Streak Shape on Rotor Heating in a High-Subsonic Single-Stage Turbine (1999)
    In:  CASI
    Details
    Publication Date: 2013-08-29
    Description: Experimental data have shown that combustor temperature non-uniformities can lead to the excessive heating of first-stage rotor blades in turbines. This heating of the rotor blades can lead to thermal fatigue and degrade turbine performance. The results of recent studies have shown that variations in the circumferential location (clocking) of the hot streak relative to the first-stage vane airfoils can be used to minimize the adverse effects of the hot streak. The effects of the hot streak/airfoil count ratio on the heating patterns of turbine airfoils have also been evaluated. In the present investigation, three-dimensional unsteady Navier-Stokes simulations have been performed for a single-stage high-pressure turbine operating in high subsonic flow. In addition to a simulation of the baseline turbine, simulations have been performed for circular and elliptical hot streaks of varying sizes in an effort to represent different combustor designs. The predicted results for the baseline simulation show good agreement with the available experimental data. The results of the hot streak simulations indicate: that a) elliptical hot streaks mix more rapidly than circular hot streaks, b) for small hot streak surface area the average rotor temperature is not a strong function of hot streak temperature ratio or shape, and c) hot streaks with larger surface area interact with the secondary flows at the rotor hub endwall, generating an additional high temperature region.
    Keywords: Aircraft Propulsion and Power
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  • 20
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    Exhaust Nozzle Materials Development for the High Speed Civil Transport (1999)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The United States has embarked on a national effort to develop the technology necessary to produce a Mach 2.4 High Speed Civil Transport (HSCT) for entry into service by the year 2005. The viability of this aircraft is contingent upon its meeting both economic and environmental requirements. Two engine components have been identified as critical to the environmental acceptability of the HSCT. These include a combustor with significantly lower emissions than are feasible with current technology, and a lightweight exhaust nozzle that meets community noise standards. The Enabling Propulsion Materials (EPM) program will develop the advanced structural materials, materials fabrication processes, structural analysis and life prediction tools for the HSCT combustor and low noise exhaust nozzle. This is being accomplished through the coordinated efforts of the NASA Lewis Research Center, General Electric Aircraft Engines and Pratt & Whitney. The mission of the EPM Exhaust Nozzle Team is to develop and demonstrate this technology by the year 1999 to enable its timely incorporation into HSCT propulsion systems.
    Keywords: Aircraft Propulsion and Power
    Type: First NASA/Industry High Speed Research Program Nozzle Symposium; 35-1 - 35-21; NASA/CP-1999-209423
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  • 21
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    High Temperature Acoustic Liner Technology (1999)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: This paper describes work currently in progress at Langley on liner concepts that employ structures that may be suitable for broadband exhaust noise attenuation in high speed flow environments and at elevated temperatures characteristic of HSCT applications. Because such liners will need to provide about 10 dB suppression over a 2 to 3 octave frequency range, conventional single-degree-of-freedom resonant structures will not suffice. Bulk absorbers have the needed broadband absorption characteristic; however, at lower frequencies they tend to be inefficient.
    Keywords: Aircraft Propulsion and Power
    Type: First NASA/Industry High Speed Research Program Nozzle Symposium; 34-1 - 34-17; NASA/CP-1999-209423
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  • 22
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    Effect of Swirl on Noise from a High Aspect Ratio Rectangular Nozzle (1999)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Based on extensive work performed by Dr. Thomas H. Sobota (Advanced Projects Research Incorporated (APRI)) on swirling flows in circular-to-rectangular transition sections, a model assembly was designed and fabricated in support of a Phase 1 Small Business Innovation Research Contract between the NASA-Langley Research Center and APRI. This assembly was acoustically tested as part of this Phase 1 effort, the goal being to determine whether the controlled introduction of axial vorticity could affect the various noise generation mechanisms present in an underexpanded supersonic rectangular jet.
    Keywords: Aircraft Propulsion and Power
    Type: First NASA/Industry High Speed Research Program Nozzle Symposium; 14-1 - 14-15; NASA/CP-1999-209423
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  • 23
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    Pratt & Whitney Two Dimensional HSR Nozzle Test in the NASA Lewis 9- By 15- Foot Low Speed Wind Tunnel: Aerodynamic Results (1999)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: This paper discusses a test that was conducted jointly by Pratt & Whitney Aircraft Engines and NASA Lewis Research Center. The test was conducted in NASA's 9- by 15-Foot Low Speed Wind Tunnel (9x15 LSWT). The test setup, methods, and aerodynamic results of this test are discussed. Acoustical results are discussed in a separate paper by J. Bridges and J. Marino.
    Keywords: Aircraft Propulsion and Power
    Type: First NASA/Industry High Speed Research Program Nozzle Symposium; 6-1 - 6-19; NASA/CP-1999-209423
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  • 24
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    High-Temperature Solid Lubricants Developed by NASA Lewis Offer Virtually "Unlimited Life" for Oil-Free Turbomachinery (1999)
    In:  CASI
    Details
    Publication Date: 2018-06-05
    Description: The NASA Lewis Research Center is capitalizing on breakthroughs in foil air bearing performance, tribological coatings, and computer analyses to formulate the Oil-free Turbomachinery Program. The program s long-term goal is to develop an innovative, yet practical, oil-free aeropropulsion gas turbine engine that floats on advanced air bearings. This type of engine would operate at higher speeds and temperatures with lower weight and friction than conventional oil-lubricated engines. During startup and shutdown, solid lubricant coatings are required to prevent wear in such engines before the self-generating air-lubrication film develops. NASA s Tribology Branch has created PS304, a chrome-oxide-based plasma spray coating specifically tailored for shafts run against foil bearings. PS304 contains silver and barium fluoride/calcium fluoride eutectic (BaF2/CaF2) lubricant additives that, together, provide lubrication from cold start temperatures to over 650 C, the maximum use temperature for foil bearings. Recent lab tests show that bearings lubricated with PS304 survive over 100 000 start-stop cycles without experiencing any degradation in performance due to wear. The accompanying photograph shows a test bearing after it was run at 650 C. The rubbing process created a "polished" surface that enhances bearing load capacity.
    Keywords: Aircraft Propulsion and Power
    Type: Research and Technology 1998; NASA/TM-1999-208815
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    Development of Field Measurement Systems for Flight Vehicle Noise (1999)
    In:  CASI
    Details
    Publication Date: 2018-06-05
    Description: Field measurement of noise radiated from flight vehicles is an important element of aircraft noise research programs. At NASA Langley, a dedicated effort that spans over two decades was devoted to the development of acoustic measurement systems to support the NASA noise research programs. The new challenge for vehicle operational noise reduction through varying glide slope and flight path require noise measurement to be made over a very large area under the vehicle flight path. Such a challenge can be met through the digital remote system currently under final development at NASA Langley.
    Keywords: Aircraft Propulsion and Power
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  • 26
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    Solid Surface Combustion Experiment Yields Significant Observations (1999)
    In:  CASI
    Details
    Publication Date: 2018-06-05
    Description: The spread of a flame over solid fuel is not only a fundamental textbook combustion phenomenon, but also the central element of destructive fires that cause tragic loss of life and property each year. Throughout history, practical measures to prevent and fight fires have been developed, but these have often been based on lessons learned in a costly fire. Since the 1960 s, scientists and engineers have employed powerful tools of scientific research to understand the details of flame spread and how a material can be rendered nonflammable. High-speed computers have enabled complex flame simulations, whereasand lasers have provided measurements of the chemical composition, temperature, and air velocities inside flames. The microgravity environment has emerged as the third great tool for these studies. Spreading flames are complex combinations of chemical reactions and several physical processes including the transport of oxygen and fuel vapor to the flame and the transfer of heat from the flame to fresh fuel and to the surroundings. Depending on its speed, air motion in the vicinity of the flame can affect the flame in substantially different ways. For example, consider the difference between blowing on a campfire and blowing out a match. On Earth, gravity induces air motion because of buoyancy (the familiar rising hot gases); this process cannot be controlled experimentally. For theoreticians, buoyant air motion complicates the problem modeling of flame spread beyond the capacity of modern computers to simulate. The microgravity environment provides experimental control of air motion near spreading flames, with results that can be compared with detailed theory. The Solid Surface Combustion Experiment (SSCE) was designed to obtain benchmark flame spreading data in quiescent test atmospheres--the limiting case of flames spreading. Professor Robert Altenkirch, Vice President for Research at Mississippi State University, proposed the experiment concept, and the NASA Lewis Research Center designed, built, and tested the SSCE hardware. It was the first microgravity science experiment built by Lewis for the space shuttle and the first combustion science experiment flown in space.
    Keywords: Aircraft Propulsion and Power
    Type: Research and Technology 1998; NASA/TM-1999-208815
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    Low-Noise Potential of Advanced Fan Stage Stator Vane Designs Verified in NASA Lewis Wind Tunnel Test (1999)
    In:  CASI
    Details
    Publication Date: 2018-06-05
    Description: With the advent of new, more stringent noise regulations in the next century, aircraft engine manufacturers are investigating new technologies to make the current generation of aircraft engines as well as the next generation of advanced engines quieter without sacrificing operating performance. A current NASA initiative called the Advanced Subsonic Technology (AST) Program has set as a goal a 6-EPNdB (effective perceived noise) reduction in aircraft engine noise relative to 1992 technology levels by the year 2000. As part of this noise program, and in cooperation with the Allison Engine Company, an advanced, low-noise, high-bypass-ratio fan stage design and several advanced technology stator vane designs were recently tested in NASA Lewis Research Center's 9- by 15-Foot Low-Speed Wind Tunnel (an anechoic facility). The project was called the NASA/Allison Low Noise Fan.
    Keywords: Aircraft Propulsion and Power
    Type: Research and Technology 1998; NASA/TM-1999-208815
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  • 28
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    Two-Dimensional Bifurcated Inlet/Engine Tests Completed in 10- by 10-Foot Supersonic Wind Tunnel (1999)
    In:  CASI
    Details
    Publication Date: 2018-06-05
    Description: A Two-Dimensional Bifurcated (2DB) Inlet was successfully tested in NASA Lewis Research Center s 10- by 10-Foot Supersonic Wind Tunnel. These tests were the culmination of a collaborative effort between the Boeing Company, General Electric, Pratt & Whitney, and Lewis. Extensive support in-house at Lewis contributed significantly to the progress and accomplishment of this test. The results, which met or exceeded many of the High-Speed Research (HSR) Program goals, were used to revise system studies within the HSR Program. The HSR Program is focused on developing low-noise, low-polluting, high-efficiency supersonic commercial aircraft. A supersonic inlet is an important component of an efficient, low-noise vehicle.
    Keywords: Aircraft Propulsion and Power
    Type: Research and Technology 1998; NASA/TM-1999-208815
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    Flutter Version of Propulsion Aeroelasticity Code Completed (1999)
    In:  CASI
    Details
    Publication Date: 2018-06-05
    Description: NASA s Advanced Subsonic Technology (AST) Program seeks to develop new technologies to increase the fuel efficiency of commercial aircraft engines, improve the safety of engine operation, and reduce emissions and engine noise. For new designs of ducted fans, compressors, and turbines to achieve these goals, a basic aeroelastic requirement is that there should be no flutter or high resonant blade stresses in the operating regime. For verifying the aeroelastic soundness of the design, an accurate prediction/analysis code is required. Such a three-dimensional viscous propulsion aeroelastic code, named TURBO-AE, is being developed at the NASA Lewis Research Center. The development and verification of the flutter version of the TURBO-AE code (version 4) has been completed. Validation of the code is partially complete.
    Keywords: Aircraft Propulsion and Power
    Type: Research and Technology 1998; NASA/TM-1999-208815
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  • 30
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    Common Analysis Tool Being Developed for Aeropropulsion: The National Cycle Program Within the Numerical Propulsion System Simulation Environment (1999)
    In:  CASI
    Details
    Publication Date: 2018-06-05
    Description: The NASA Lewis Research Center is developing an environment for analyzing and designing aircraft engines-the Numerical Propulsion System Simulation (NPSS). NPSS will integrate multiple disciplines, such as aerodynamics, structure, and heat transfer, and will make use of numerical "zooming" on component codes. Zooming is the coupling of analyses at various levels of detail. NPSS uses the latest computing and communication technologies to capture complex physical processes in a timely, cost-effective manner. The vision of NPSS is to create a "numerical test cell" enabling full engine simulations overnight on cost-effective computing platforms. Through the NASA/Industry Cooperative Effort agreement, NASA Lewis and industry partners are developing a new engine simulation called the National Cycle Program (NCP). NCP, which is the first step toward NPSS and is its initial framework, supports the aerothermodynamic system simulation process for the full life cycle of an engine. U.S. aircraft and airframe companies recognize NCP as the future industry standard common analysis tool for aeropropulsion system modeling. The estimated potential payoff for NCP is a $50 million/yr savings to industry through improved engineering productivity.
    Keywords: Aircraft Propulsion and Power
    Type: Research and Technology 1998; NASA/TM-1999-208815
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    Affordable Manufacturing Technologies Being Developed for Actively Cooled Ceramic Components (1999)
    In:  CASI
    Details
    Publication Date: 2018-06-02
    Description: Efforts to improve the performance of modern gas turbine engines have imposed increasing service temperature demands on structural materials. Through active cooling, the useful temperature range of nickel-base superalloys in current gas turbine engines has been extended, but the margin for further improvement appears modest. Because of their low density, high-temperature strength, and high thermal conductivity, in situ toughened silicon nitride ceramics have received a great deal of attention for cooled structures. However, high processing costs have proven to be a major obstacle to their widespread application. Advanced rapid prototyping technology, which is developing rapidly, offers the possibility of an affordable manufacturing approach.
    Keywords: Aircraft Propulsion and Power
    Type: Research and Technology 1998; NASA/TM-1999-208815
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    Flow of GE90 Turbofan Engine Simulated (1999)
    In:  CASI
    Details
    Publication Date: 2018-06-05
    Description: The objective of this task was to create and validate a three-dimensional model of the GE90 turbofan engine (General Electric) using the APNASA (average passage) flow code. This was a joint effort between GE Aircraft Engines and the NASA Lewis Research Center. The goal was to perform an aerodynamic analysis of the engine primary flow path, in under 24 hours of CPU time, on a parallel distributed workstation system. Enhancements were made to the APNASA Navier-Stokes code to make it faster and more robust and to allow for the analysis of more arbitrary geometry. The resulting simulation exploited the use of parallel computations by using two levels of parallelism, with extremely high efficiency.The primary flow path of the GE90 turbofan consists of a nacelle and inlet, 49 blade rows of turbomachinery, and an exhaust nozzle. Secondary flows entering and exiting the primary flow path-such as bleed, purge, and cooling flows-were modeled macroscopically as source terms to accurately simulate the engine. The information on these source terms came from detailed descriptions of the cooling flow and from thermodynamic cycle system simulations. These provided boundary condition data to the three-dimensional analysis. A simplified combustor was used to feed boundary conditions to the turbomachinery. Flow simulations of the fan, high-pressure compressor, and high- and low-pressure turbines were completed with the APNASA code.
    Keywords: Aircraft Propulsion and Power
    Type: Research and Technology 1998; NASA/TM-1999-208815
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    Composite Nozzle/Thrust Chambers Analyzed for Low-Cost Boosters (1999)
    In:  CASI
    Details
    Publication Date: 2018-06-05
    Description: The Low Cost Booster Technology Program is an initiative to minimize the cost of future liquid engines by using advanced materials and innovative designs, and by reducing engine complexity. NASA Marshall Space Flight Center s 60K FASTRAC Engine is one example where these design philosophies have been put into practice. This engine burns a liquid kerosene/oxygen mixture. It uses a one-piece, polymer composite thrust chamber/nozzle that is constructed of a tape-wrapped silica phenolic liner, a metallic injector interface ring, and a filament-wound epoxy overwrap. A cooperative effort between NASA Lewis Research Center s Structures Division and Marshall is underway to perform a finite element analysis of the FASTRAC chamber/nozzle under all the loading and environmental conditions that it will experience during its lifetime. The chamber/nozzle is a complex composite structure. Of its three different materials, the two composite components have distinctly different fiber architectures and, consequently, require separate material model descriptions. Since the liner is tape wrapped, it is orthotropic in the nozzle global coordinates; and since the overwrap is filament wound, it is treated as a monoclinic material. Furthermore, the wind angle on the overwrap varies continuously along the length of the chamber/nozzle.
    Keywords: Aircraft Propulsion and Power
    Type: Research and Technology 1998; NASA/TM-1999-208815
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    Distortion Tolerant Control Flight Demonstration Shown to Be Successful (1999)
    In:  CASI
    Details
    Publication Date: 2018-06-05
    Description: Future aircraft turbine engines, both commercial and military, will have to be able to successfully accommodate expected increased levels of steady-state and dynamic engine-face distortion. Advanced tactical aircraft are likely to use thrust vectoring for enhanced aircraft maneuverability. As a result, the engines will see more extreme distortion levels than currently encountered with present-day aircraft. Also, the mixed-compression inlets needed for the High-Speed Civil Transport (HSCT) will likely encounter disturbances similar to those seen by tactical aircraft, in addition to planar pulse, inlet buzz, and high distortion levels at low flight speed and off-design operation. The current approach of incorporating sufficient component design stall margin to tolerate these expected levels of distortion would result in significant performance penalties. The objectives of NASA's High Stability Engine Control (HISTEC) program, which has reached a highly successful conclusion, were to design, develop, and flight demonstrate an advanced, high-stability, integrated engine control system that uses measurement-based real-time estimates of distortion to enhance engine stability. The resulting distortion tolerant control adjusts the stall margin requirement online in real time. This reduces the design stall margin requirement, with a corresponding increase in performance and decrease in fuel burn.
    Keywords: Aircraft Propulsion and Power
    Type: Research and Technology 1998; NASA/TM-1999-208815
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  • 35
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    XV-15 Tiltrotor Low Noise Approach Operations (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Acoustic data have been acquired for the XV-15 tiltrotor aircraft performing approach operations for a variety of different approach profile configurations. This flight test program was conducted jointly by NASA, the U.S. Army, and Bell Helicopter Textron, Inc. (BHTI) in June 1997. The XV-15 was flown over a large area microphone array, which was deployed to directly measure the noise footprint produced during actual approach operations. The XV-15 flew realistic approach profiles that culminated in IGE hover over a landing pad. Aircraft tracking and pilot guidance was provided by a Differential Global Positioning System (DGPS) and a flight director system developed at BHTI. Approach profile designs emphasized noise reduction while maintaining handling qualities sufficient for tiltrotor commercial passenger ride comfort and flight safety under Instrument Flight Rules (IFR) conditions. A discussion of the approach profile design philosophy is provided. Five different approach profiles are discussed in detail -- 3 deg., 6 deg., and 9 deg. approaches, and two very different 3 deg. to 9 deg. segmented approaches. The approach profile characteristics are discussed in detail, followed by the noise footprints and handling qualities. Sound exposure levels are also presented on an averaged basis and as a function of the sideline distance for a number of up-range distances from the landing point. A comparison of the noise contour areas is also provided. The results document the variation in tiltrotor noise due to changes in operating condition, and indicate the potential for significant noise reduction using the unique tiltrotor capability of nacelle tilt.
    Keywords: Aircraft Propulsion and Power
    Type: American Helicopter Society 55th Annual Forum; May 25, 1999 - May 27, 1999; Montreal, Quebec; Canada
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    Tiltrotor Aeroacoustic Code (TRAC) Prediction Assessment and Initial Comparisons with Tram Test Data (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A prediction sensitivity assessment to inputs and blade modeling is presented for the TiltRotor Aeroacoustic Code (TRAC). For this study, the non-CFD prediction system option in TRAC is used. Here, the comprehensive rotorcraft code, CAMRAD.Mod1, coupled with the high-resolution sectional loads code HIRES, predicts unsteady blade loads to be used in the noise prediction code WOPWOP. The sensitivity of the predicted blade motions, blade airloads, wake geometry, and acoustics is examined with respect to rotor rpm, blade twist and chord, and to blade dynamic modeling. To accomplish this assessment, an interim input-deck for the TRAM test model and an input-deck for a reference test model are utilized in both rigid and elastic modes. Both of these test models are regarded as near scale models of the V-22 proprotor (tiltrotor). With basic TRAC sensitivities established, initial TRAC predictions are compared to results of an extensive test of an isolated model proprotor. The test was that of the TiltRotor Aeroacoustic Model (TRAM) conducted in the Duits-Nederlandse Windtunnel (DNW). Predictions are compared to measured noise for the proprotor operating over an extensive range of conditions. The variation of predictions demonstrates the great care that must be taken in defining the blade motion. However, even with this variability, the predictions using the different blade modeling successfully capture (bracket) the levels and trends of the noise for conditions ranging from descent to ascent.
    Keywords: Aircraft Propulsion and Power
    Type: 25th European Rotorcraft Forum; Sep 14, 1999 - Sep 16, 1999; Rome; Italy
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    Inlet Noise Reduction by Shielding for the Blended-Wing-Body Airplane (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Noise shielding benefits associated with an advanced unconventional subsonic transport concept, the Blended-Wing-Body, were studied using a 4- percent scale, 3-engine nacelle model. The study was conducted in the Anechoic Noise Research Facility at NASA Langley Research Center. A high- frequency, wideband point source was placed inside the nacelles of the center engine and one of the side engines in order to simulate broadband engine noise. The sound field of the model was measured with a rotating microphone array that was moved to various stations along the model axis and with a fixed array of microphones that was erected behind the model. Ten rotating microphones were traversed a total of 22 degrees in 2-degree increments. Seven fixed microphones covered an arc that extended from a point in the exhaust exit plane of the center engine (and directly below its centerline) to a point 30 degrees above the jet centerline. While no attempt was made to simulate the noise emission characteristics of an aircraft engine, the model source was intended to radiate sound in a frequency range encompassing 1, 2, and 3 times the blade passage of a typical full-scale engine. In this study, the Blended-Wing-Body model was found to provide significant shielding of inlet noise. In particular, noise radiated downward into the forward sector was reduced by 20 to 25 dB overall in the full-scale frequencies from 2000 to 4000 Hz, decreasing to 10 dB or less at the lower frequencies. Also, it was observed that noise associated with the exhaust radiates into the sector directly below the model downstream to reduce shielding efficiency.
    Keywords: Aircraft Propulsion and Power
    Type: AIAA Paper 99-1937 , 5th AIAA/CEAS Aeroacoustics Conference; May 10, 1999 - May 12, 1999; Greater Seattle, WA; United States
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    Simulation of Acoustic Scattering from a Trailing Edge (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Three model problems were examined to assess the difficulties involved in using a hybrid scheme coupling flow computation with the the Ffowcs Williams and Hawkings equation to predict noise generated by vortices passing over a sharp edge. The results indicate that the Ffowcs Williams and Hawkings equation correctly propagates the acoustic signals when provided with accurate flow information on the integration surface. The most difficult of the model problems investigated inviscid flow over a two-dimensional thin NACA airfoil with a blunt-body vortex generator positioned at 98 percent chord. Vortices rolled up downstream of the blunt body. The shed vortices possessed similarities to large coherent eddies in boundary layers. They interacted and occasionally paired as they convected past the sharp trailing edge of the airfoil. The calculations showed acoustic waves emanating from the airfoil trailing edge. Acoustic directivity and Mach number scaling are shown.
    Keywords: Aircraft Propulsion and Power
    Type: AIAA Paper 99-0231 , Aerospace Sciences Meeting and Exhibit; Jan 11, 1999 - Jan 14, 1999; Reno, NV; United States
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  • 39
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    Acoustic Energy Estimates in Inhomogeneous Moving Media (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: In ducted fan engine noise research, there is a need for defining a simple and easy to use acoustic energy conservation law to help in quantification of noise control techniques. There is a well known conservation law relating acoustic energy and acoustic energy flux in the case of an isentropic irrotational flow. Several different approaches have been taken to generalize this conservation law. For example, Morfey finds an identity by separating out the irrotational part of the perturbed flow. Myers is able to find a series of indentities by observing an algebraic relationship between the basic conservation of energy equation for a background flow and the underlying equations of motion. In an approximate sense, this algebraic relationship is preserved under perturbation. A third approach which seems to have not been pursued in the literature is a result known as Noether's theorem. There is a Lagrangian formulation for the Euler equation of fluid mechanics. Noether's theorem says that any group action that leaves the Lagrangian action invariant leads to a conserved quantity. This presentation will include a survey of current results regarding acoustic energy and preliminary results on the symmetries of the Lagrangian.
    Keywords: Aircraft Propulsion and Power
    Type: Joint ASA/EAA/DAGA Meeting; Mar 14, 1999 - Mar 19, 1999; Berlin; Germany
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  • 40
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    DRACO Flowpath Performance and Environments (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The Advanced Space Transportation (AST) project office has challenged NASA to design, manufacture, ground-test and flight-test an axisymmetric, hydrocarbon-fueled, flight-weight, ejector-ramjet engine system testbed no later than 2005. To accomplish this, a multi-center NASA team has been assembled. The goal of this team, led by NASA-Marshall Space Flight Center (MSFC), is to develop propulsion technologies that demonstrate rocket and airbreathing combined-cycle operation (DRACO). Current technical activities include flowpath conceptual design, engine systems conceptual design, and feasibility studies investigating the integration and operation of the DRACO engine with a Lockheed D-21B drone. This paper focuses on the activities of the Flowpath Systems Product Development Team (PDT), led by NASA-Glenn Research Center (GRC) and supported by NASA-MSFC and TechLand Research, Inc. The objective of the Flowpath PDT at the start of the DRACO program was to establish a conceptual design of the flowpath aerodynamic lines, determine the preliminary performance, define the internal environments, and support the DRACO testbed concept feasibility studies. To accomplish these tasks, the PDT convened to establish a baseline flowpath concept. With the conceptual lines defined, cycle analysis tasks were planned and the flowpath performance and internal environments were defined. Additionally, sensitivity studies investigating the effects of inlet reference area, combustion performance, and combustor/nozzle materials selection were performed to support the Flowpath PDT design process. Results of these tasks are the emphasis of this paper and are intended to verify the feasibility of the DRACO flowpath and engine system as well as identify the primary technical challenges inherent in the flight-weight design of an advanced propulsion technology demonstration engine. Preliminary cycle performance decks were developed to support the testbed concept feasibility studies but are not discussed further in this paper.
    Keywords: Aircraft Propulsion and Power
    Type: Propulsion; Nov 18, 1999 - Nov 19, 1999; University Park, PA; United States
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    SiC/SiC Leading Edge Turbine Airfoil Tested Under Simulated Gas Turbine Conditions (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Silicon-based ceramics have been proposed as component materials for use in gas turbine engine hot-sections. A high pressure burner rig was used to expose both a baseline metal airfoil and ceramic matrix composite leading edge airfoil to typical gas turbine conditions to comparatively evaluate the material response at high temperatures. To eliminate many of the concerns related to an entirely ceramic, rotating airfoil, this study has focused on equipping a stationary metal airfoil with a ceramic leading edge insert to demonstrate the feasibility and benefits of such a configuration. Here, the idea was to allow the SiC/SiC composite to be integrated as the airfoil's leading edge, operating in a "free-floating" or unrestrained manner. and provide temperature relief to the metal blade underneath. The test included cycling the airfoils between simulated idle, lift, and cruise flight conditions. In addition, the airfoils were air-cooled, uniquely instrumented, and exposed to the same internal and external conditions, which included gas temperatures in excess of 1370 C (2500 F). Results show the leading edge insert remained structurally intact after 200 simulated flight cycles with only a slightly oxidized surface. The instrumentation clearly suggested a significant reduction (approximately 600 F) in internal metal temperatures as a result of the ceramic leading edge. The object of this testing was to validate the design and analysis done by Materials Research and Design of Rosemont, PA and to determine the feasibility of this design for the intended application.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/CR-1999-209314 , E-11919 , NAS 1.26:209314 , Composites, Materials and Structures; Jan 25, 1999 - Jan 29, 1999; Cocoa Beach, FL; United States
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    First NASA/Industry High Speed Research Program Nozzle Symposium (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The First High Speed Research (HSR) Nozzle Symposium was hosted by NASA Lewis Research Center on November 17-19, 1992 in Cleveland, Ohio, and was sponsored by the HSR Source Noise Working Group. The purpose of this symposium was to provide a national forum for the government, industry, and university participants in the program to present and discuss important low noise nozzle research results and technology issues related to the development of appropriate nozzles for a commercially viable, environmentally compatible, U.S. High-Speed Civil Transport. The HSR Phase I research program was initiated in FY90 and is approaching the first major milestone (end of FY92) relative to an initial FAR 36 Stage 3 nozzle noise assessment. Significant research results relative to that milestone were presented. The opening session provided a brief overview of the Program and status of the Phase H plan. The next five sessions were technically oriented and highlighted recent significant analytical and experimental accomplishments. The last Session included a panel discussion by the Session Chairs, summarizing the progress seen to date and discussing issues relative to further advances in technology necessary to achieve the Program Goals. Attendance at the Symposium was by invitation only and included only industry, academic, and government participants who are actively involved in the High-Speed Research Program. The technology presented in this meeting is considered commercially sensitive.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/CP-1999-209423 , E-11937 , NAS 1.55:209423 , First NASA/Industry High Speed Research Program Nozzle Symposium|Nov 17, 1992 - Nov 22, 1992; Cleveland, OH; United States
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    Multistage Simulations of the GE90 Turbine (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The average passage approach has been used to analyze three multistage configurations of the GE90 turbine. These are a high pressure turbine rig, a low pressure turbine rig and a full turbine configuration comprising 18 blade rows of the GE90 engine at takeoff conditions. Cooling flows in the high pressure turbine have been simulated using source terms. This is the first time a dual-spool cooled turbine has been analyzed in 3D using a multistage approach. There is good agreement between the simulations and experimental results. Multistage and component interaction effects are also presented. The parallel efficiency of the code is excellent at 87.3% using 121 processors on an SGI Origin for the 18 blade row configuration. The accuracy and efficiency of the calculation now allow it to be effectively used in a design environment so that multistage effects can be accounted for in turbine design.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/CR-1999-209311 , E-11880 , NAS 1.26:209311 , Gas Turbine and Aeroengine Congress; Jun 07, 1999 - Jun 10, 1999; Indianapolis, IN; United States
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    NASA Glenn Research Center's Hypersonic Propulsion Program (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: NASA Glenn Research Center (GRC), as NASA's lead center for aeropropulsion, is responding to the challenge of reducing the cost of space transportation through the integration of air-breathing propulsion into launch vehicles. Air- breathing launch vehicle (ABLV) propulsion requires a marked departure from traditional propulsion applications. and stretches the technology of both rocket and air-breathing propulsion. In addition, the demands of the space launch mission require an unprecedented level of integration of propulsion and vehicle systems. GRC is responding with a program with rocket-based combined cycle (RBCC) propulsion technology as its main focus. RBCC offers the potential for simplicity, robustness, and performance that may enable low-cost single-stage-to-orbit (SSTO) transportation. Other technologies, notably turbine-based combined cycle (TBCC) propulsion, offer benefits such as increased robustness and greater mission flexibility, and are being advanced, at a slower pace, as part of GRC's program in hypersonics.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-1999-209185 , E-11696 , NAS 1.15:209185 , Airbreathing Engines; Sep 05, 1999 - Sep 10, 1999; Florence; Italy
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    Overview of Current Turbine Aerodynamic Analysis and Testing at MSFC (1999)
    In:  Other Sources
    Details
    Publication Date: 2019-07-17
    Description: An overview of the current turbine aerodynamic analysis and testing activities at NASA/Marshall Space Flight Center (MSFC) is presented. The presentation is divided into three areas. The first area is the three-dimensional (3D), unsteady Computational Fluid Dynamics (CFD) analysis of the Fastrac turbine. Results from a coupled nozzle, blade, and exit guide vane analysis and from an uncoupled nozzle and coupled blade and exit guide vane will be presented. Unsteady pressure distributions, frequencies, and exit profiles from each analysis will be compared and contrasted. The second area is the testing and analysis of the Space Shuttle Main Engine (SSME) High Pressure Fuel Turbopump (HPFTP) turbine with instrumented first stage blades. The SSME HPFTP turbine was tested in air at the MSFC Turbine Test Equipment (TTE). Pressure transducers were mounted on the first stage blades. Unsteady, 3D CFD analysis was performed for this geometry and flow conditions. A sampling of the results will be shown. The third area is a status of the Turbine Performance Optimization task. The objective of this task is to improve the efficiency of a turbine for potential use on a next generation launch vehicle. This task includes global optimization for the preliminary design, detailed optimization for blade shapes and spacing, and application of advanced CFD analysis. The final design will be tested in the MSFC TTE.
    Keywords: Aircraft Propulsion and Power
    Type: Thermal and Fluids Analysis; Sep 13, 1999 - Sep 17, 1999; Huntsville, AL; United States
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    A Mode Detection Method Using the Azimuthal Directivity of a Turbofan Model (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: The azimuthal, far field directivity of a scale fan model was measured in high resolution. The model is a 12 inch diameter rotor with 16 blades followed by 40 stator vanes. The tests were conducted at the nominal 100% speed corresponding to a tip speed of 905 ft/sec. Measurement of the radiated sound field, forward of the fan, was made in an anechoic chamber with an inflow control device and a baffle separating the aft and forward radiated interaction noise. The acoustic field was surveyed with a circular hoop array of 16 microphones which was moved to 14 axial stations. At each axial station the hoop was rotated in half-degree increments to take 736 points in the azimuthal angle. In addition to sound pressure level, the phase angle relative to a reference microphone was measured at each point. The sound pressure level is shown to vary in patterns by 10-15 dB especially for the fundamental tone but also for the first and second harmonic. A far field mode detection method has been developed and used with the data which determines the modes generated by the fan and which then interact to form the azimuthal directivity.
    Keywords: Aircraft Propulsion and Power
    Type: AIAA Paper 99-1954
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    Overview of Rocket Propulsion Testing at NASA Stennis Space Center (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: THe recent nationwide thrust toward development of low-cost space transportation has precipitated a sharp increase in demand for subscale and full-scale propulsion test services. This paper highlights the unique capabilities of Stennis Space Center(SSC) to meet these demands, and summarizes several major propulsion test activities and other related milestone achievements during the 1999 calendar year. The current and projected list of SSC test projects heralds an even more vigorous, interesting, and challenging future in propulsion test.
    Keywords: Aircraft Propulsion and Power
    Type: SE-1999-11-00024-SSC
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  • 48
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    Turbofan engine with a low pressure turbine driven supercharger in a bypass duct operated by a fuel rich combustor and an afterburner (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: A multiple bypass turbofan engine includes a core Brayton Cycle gas generator with a fuel rich burning combustor and is provided with a variable supercharged bypass duct around the gas generator with a supercharging means in the supercharged bypass duct powered by a turbine not mechanically connected to the gas generator. The engine further includes a low pressure turbine driven forward fan upstream and forward of an aft fan and drivingly connected to a low pressure turbine by a low pressure shaft, the low pressure turbine being aft of and in serial flow communication with the core gas generator. A fan bypass duct is disposed radially outward of the core engine assembly and has first and second inlets disposed between the forward and aft fans. An inlet duct having an annular duct wall is disposed radially inward of the bypass duct and connects the second inlet to the bypass duct. A supercharger means for compressing air is drivingly connected to the low pressure turbine and is disposed in the inlet duct. A secondary combustor or augmentor is disposed in an exhaust duct downstream of and in fluid flow communication with the bypass duct and the gas generator.
    Keywords: Aircraft Propulsion and Power
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  • 49
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    Fuel control system for an engine (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: A fuel control system responsive to a power controller and controlling a fuel delivery system. The fuel control system includes a control arm connected to both the power controller and the fuel delivery system, a position sensor connected to the control arm, and a trim controller connected to the control arm at a pivot point and connected to the position sensor.
    Keywords: Aircraft Propulsion and Power
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  • 50
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    Flight Test of ASAC Aircraft Interior Noise Control System (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: A flight test is described in which an active structural/acoustic control system reduces turboprop induced interior noise on a Raytheon Aircraft Company 1900D airliner. Control inputs to 21 inertial force actuators were computed adaptively using a transform domain version of the multichannel filtered-X LMS algorithm to minimize the mean square response of 32 microphones. A combinatorial search algorithm was employed to optimize placement of the force actuators on the aircraft frame. Both single frequency and multi-frequency results are presented. Reductions of up to 15 dB were obtained at the blade passage frequency (BPF) during single frequency control tests. Simultaneous reductions of the BPF and next 2 harmonics of 10 dB, 2.5 dB and 3.0 dB, were obtained in a multi-frequency test.
    Keywords: Aircraft Propulsion and Power
    Type: AIAA Paper 99-1933
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    The Design of Future Airbreathing Engine Systems within an Intelligent Synthesis Environment (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: This paper describes a new Initiative proposed by the National Aeronautics and Space Administration (NASA). The purpose of this initiative is to develop a future design environment for engineering and science mission synthesis for use by NASA scientists and engineers. This new initiative is called the Intelligent Synthesis Environment (ISE). The paper describes the mission of NASA, future aerospace system characteristics, the current engineering design process, the ISE concept, and concludes with a description of possible ISE applications for the decision of air-breathing propulsion systems.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-1999-209192 , NAS 1.15:209192 , E-11706 , 14th International on Air Breathing Engines; Sep 05, 1999 - Sep 10, 1999; Florence; Italy
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  • 52
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    Performance and Durability of High Temperature Foil Air Bearing for Oil-Free Turbomachinery (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The performance and durability of advanced, high temperature foil air bearings are evaluated under a wide range (10-50 kPa) of loads at temperatures from 25 to 650 C. The bearings are made from uncoated nickel based superalloy foils. The foil surface experiences sliding contact with the shaft during initial start/stop operation. To reduce friction and wear, the solid lubricant coating, PS304, is applied to the shaft by plasma spraying. PS304, is a NiCr based Cr2O3 coating with silver and barium fluoride/calcium fluoride solid lubricant additions. The results show that the bearings provide lives well in excess of 30,000 cycles under all of the conditions tested. Several bearings exhibited lives in excess of 100,000 cycles. Wear is a linear function of the bearing load. The excellent performance measured in this study suggests that these bearings and the PS304 coating are well suited for advanced high temperature, oil-free turbomachinery applications.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-1999-209187 , NAS 1.15:209187 , E-11697 , May 07, 2000 - May 11, 2000; Nashville, TN; United States
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    The Numerical Propulsion System Simulation: A Multidisciplinary Design System for Aerospace Vehicles (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Advances in computational technology and in physics-based modeling are making large scale, detailed simulations of complex systems possible within the design environment. For example, the integration of computing, communications, and aerodynamics has reduced the time required to analyze ma or propulsion system components from days and weeks to minutes and hours. This breakthrough has enabled the detailed simulation of major propulsion system components to become a routine part of design process and to provide the designer with critical information about the components early in the design process. This paper describes the development of the Numerical Propulsion System Simulation (NPSS), a multidisciplinary system of analysis tools that is focussed on extending the simulation capability from components to the full system. This will provide the product developer with a "virtual wind tunnel" that will reduce the number of hardware builds and tests required during the development of advanced aerospace propulsion systems.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-1999-209194 , NAS 1.15:209194 , E-11708 , Air Breathing Engines; Sep 05, 1999 - Sep 10, 1999; Florence; Italy
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    [Component and System Level of the FASTRAC Engine] (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The primary activities of Lee & Associates during the period 7/20/99 to 12/31/99 as specified in the referenced Purchase Order has been in direct support of the Advanced Space Technology Program OfFice's Core Propulsion Project. An independent review to assess the program readiness to conduct component and system level testing of the FASTRAC Engine and to proceed into Fabrication has been provided. This was accomplished through the identification of program weaknesses and potential failure areas and where applicable recommended solutions were suggested to the Program Office that would mitigate technical and program risk. The approach taken to satisfy the objectives has been for the contractor to provide a team of experts with relevant experience from past programs and a strong background of experience in the fields critical to the success of the program. The team participated in Test Planning, Test Readiness Reviews for system testing at Stennis Space Center, Anomaly Resolution Reviews, an Operations Audit, and data analysis. This approach worked well in satisfying the objectives and providing the Project Office with valuable information in real time and through monthly reports. During the month of December 1999 the primary effort involved the participation in anomaly resolution and the detailed review of the data from the final H3 and H4 test series performed on the FASTRAC engine in the b-2 Horizontal Test Facility at Stennis. The more significant findings and recommendations from this review are presented in this report.
    Keywords: Aircraft Propulsion and Power
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    TADS: A CFD-Based Turbomachinery Analysis and Design System with GUI: Methods and Results (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The primary objective of this study was the development of a Computational Fluid Dynamics (CFD) based turbomachinery airfoil analysis and design system, controlled by a Graphical User Interface (GUI). The computer codes resulting from this effort are referred to as TADS (Turbomachinery Analysis and Design System). This document is the Final Report describing the theoretical basis and analytical results from the TADS system developed under Task 10 of NASA Contract NAS3-27394, ADPAC System Coupling to Blade Analysis & Design System GUI, Phase II-Loss, Design and. Multi-stage Analysis. TADS couples a throughflow solver (ADPAC) with a quasi-3D blade-to-blade solver (RVCQ3D) or a 3-D solver with slip condition on the end walls (B2BADPAC) in an interactive package. Throughflow analysis and design capability was developed in ADPAC through the addition of blade force and blockage terms to the governing equations. A GUI was developed to simplify user input and automate the many tasks required to perform turbomachinery analysis and design. The coupling of the various programs was done in such a way that alternative solvers or grid generators could be easily incorporated into the TADS framework. Results of aerodynamic calculations using the TADS system are presented for a multistage compressor, a multistage turbine, two highly loaded fans, and several single stage compressor and turbine example cases.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/CR-1999-206603 , E-11116 , NAS 1.26:206603
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    A Neural Network Aero Design System for Advanced Turbo-Engines (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: An inverse design method calculates the blade shape that produces a prescribed input pressure distribution. By controlling this input pressure distribution the aerodynamic design objectives can easily be met. Because of the intrinsic relationship between pressure distribution and airfoil physical properties, a neural network can be trained to choose the optimal pressure distribution that would meet a set of physical requirements. The neural network technique works well not only as an interpolating device but also as an extrapolating device to achieve blade designs from a given database. Two validating test cases are discussed.
    Keywords: Aircraft Propulsion and Power
    Type: Air Breathing Engines; Sep 05, 1999 - Sep 10, 1999; Florence; Italy
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    Wave-Rotor-Enhanced Gas Turbine Engine Demonstrator (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The U.S. Army Research Laboratory, NASA Glenn Research Center, and Rolls-Royce Allison are working collaboratively to demonstrate the benefits and viability of a wave-rotor-topped gas turbine engine. The self-cooled wave rotor is predicted to increase the engine overall pressure ratio and peak temperature by 300% and 25 to 30%. respectively, providing substantial improvements in engine efficiency and specific power. Such performance improvements would significantly reduce engine emissions and the fuel logistics trails of armed forces. Progress towards a planned demonstration of a wave-rotor-topped Rolls-Royce Allison model 250 engine has included completion of the preliminary design and layout of the engine, the aerodynamic design of the wave rotor component and prediction of its aerodynamic performance characteristics in on- and off-design operation and during transients, and the aerodynamic design of transition ducts between the wave rotor and the high pressure turbine. The topping cycle increases the burner entry temperature and poses a design challenge to be met in the development of the demonstrator engine.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-1999-209459 , NAS 1.15:209459 , ARL-TR-2113 , E-11958 , Gas Turbine Operation and Technology for Land, Sea and Air Propulsion and Power Systems; Oct 18, 1999 - Oct 21, 1999; Ottawa; Canada
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    A Three-Dimensional Coupled Internal/External Simulation of a Film-Cooled Turbine Vane (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A three-dimensional Navier-Stokes simulation has been performed for a realistic film-cooled turbine vane using the LeRC-HT code. The simulation includes the flow regions inside the coolant plena and film cooling holes in addition to the external flow. The vane is the subject of an upcoming NASA Glenn Research Center experiment and has both circular cross-section and shaped film cooling holes. This complex geometry is modeled using a multi-block grid which accurately discretizes the actual vane geometry including shaped holes. The simulation matches operating conditions for the planned experiment and assumes periodicity in the spanwise direction on the scale of one pitch of the film cooling hole pattern. Two computations were performed for different isothermal wall temperatures, allowing independent determination of heat transfer coefficients and film effectiveness values. The results indicate separate localized regions of high heat transfer coefficient values, while the shaped holes provide a reduction in heat flux through both parameters. Hole exit data indicate rather simple skewed profiles for the round holes, but complex profiles for the shaped holes with mass fluxes skewed strongly toward their leading edges.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-1999-209078 , NAS 1.15:209078 , E-11638 , Gas Turbine and Aeroengine Congress, Exposition and Users'' Symposium; Jun 07, 1999 - Jun 10, 1999; Indianapolis, IN; United States
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    Parametric Studies of the Ejector Process within a Turbine-Based Combined-Cycle Propulsion System (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Performance characteristics of the ejector process within a turbine-based combined-cycle (TBCC) propulsion system are investigated using the NPARC Navier-Stokes code. The TBCC concept integrates a turbine engine with a ramjet into a single propulsion system that may efficiently operate from takeoff to high Mach number cruise. At the operating point considered, corresponding to a flight Mach number of 2.0, an ejector serves to mix flow from the ramjet duct with flow from the turbine engine. The combined flow then passes through a diffuser where it is mixed with hydrogen fuel and burned. Three sets of fully turbulent Navier-Stokes calculations are compared with predictions from a cycle code developed specifically for the TBCC propulsion system. A baseline ejector system is investigated first. The Navier-Stokes calculations indicate that the flow leaving the ejector is not completely mixed, which may adversely affect the overall system performance. Two additional sets of calculations are presented; one set that investigated a longer ejector region (to enhance mixing) and a second set which also utilized the longer ejector but replaced the no-slip surfaces of the ejector with slip (inviscid) walls in order to resolve discrepancies with the cycle code. The three sets of Navier-Stokes calculations and the TBCC cycle code predictions are compared to determine the validity of each of the modeling approaches.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-1999-209172 , NAS 1.15:209172 , AIAA Paper 98-0936 , E-11679 , Aerospace Sciences; Jan 12, 1998 - Jan 15, 1998; Reno, NV; United States
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    Comparison of Techniques for Non-Intrusive Fuel Drop Size Measurements in a Subscale Gas Turbine Combustor (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: In aviation gas turbine combustors, many factors, such as the degree and extent of fuel/air mixing and fuel vaporization achieved prior to combustion, influence the formation of undesirable pollutants. To assist in analyzing the extent of fuel/air mixing, flow visualization techniques have been used to interrogate the fuel distributions during subcomponent tests of lean-burning fuel injectors. Discrimination between liquid and vapor phases of the fuel was determined by comparing planar laser-induced fluorescence (PLIF) images, elastically-scattered light images, and phase/Doppler interferometer measurements. Estimates of Sauter mean diameters are made by ratioing PLIF and Mie scattered intensities for various sprays, and factors affecting the accuracy of these estimates are discussed. Mie calculations of absorption coefficients indicate that the fluorescence intensities of individual droplets are proportional to their surface areas, instead of their volumes, due to the high absorbance of the liquid fuel for the selected excitation wavelengths.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-1999-208909 , NAS 1.15:208909 , E-11523 , Optical Technology and Image Processing in Fluid, Thermal, and Combustion Flow; Dec 06, 1998 - Dec 10, 1998; Yokohama; Japan
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    Study of Boundary Layer Development in a Two-Stage Low-Pressure Turbine (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Experimental data from jet-engine tests have indicated that unsteady blade row interactions and separation can have a significant impact on the efficiency of low-pressure turbine stages. Measured turbine efficiencies at takeoff can be as much as two points higher than those at cruise conditions. Several recent studies have revealed that Reynolds number effects may contribute to the lower efficiencies at cruise conditions. In the current study numerical simulations have been performed to study the boundary layer development in a two-stage low-pressure turbine, and to evaluate the transition models available for low Reynolds number flows in turbomachinery. The results of the simulations have been compared with experimental data, including airfoil loadings and integral boundary layer quantities. The predicted unsteady results display similar trends to the experimental data, but significantly overestimate the amplitude of the unsteadiness. The time-averaged results show close agreement with the experimental data.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-1999-208913 , E-11544 , AIAA Paper 99-0742 , NAS 1.15:208913 , Aerospace Sciences; Jan 11, 1999 - Jan 14, 1999; Reno, NV; United States
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    Development and Validation of a Supersonic Helium-Air Coannular Jet Facility (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: Data are acquired in a simple coannular He/air supersonic jet suitable for validation of CFD (Computational Fluid Dynamics) codes for high speed propulsion. Helium is employed as a non-reacting hydrogen fuel simulant, constituting the core of the coannular flow while the coflow is composed of air. The mixing layer interface between the two flows in the near field and the plume region which develops further downstream constitute the primary regions of interest, similar to those present in all hypersonic air breathing propulsion systems. A computational code has been implemented from the experiment's inception, serving as a tool for model design during the development phase.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/CR-1999-209717 , NAS 1.26:209717
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    Advanced Subsonic Technology (AST) Area of Interest (AOI) 6: Develop and Validate Aeroelastic Codes for Turbomachinery (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: AlliedSignal Engines, in cooperation with NASA GRC (National Aeronautics and Space Administration Glenn Research Center), completed an evaluation of recently-developed aeroelastic computer codes using test cases from the AlliedSignal Engines fan blisk and turbine databases. Test data included strain gage, performance, and steady-state pressure information obtained for conditions where synchronous or flutter vibratory conditions were found to occur. Aeroelastic codes evaluated included quasi 3-D UNSFLO (MIT Developed/AE Modified, Quasi 3-D Aeroelastic Computer Code), 2-D FREPS (NASA-Developed Forced Response Prediction System Aeroelastic Computer Code), and 3-D TURBO-AE (NASA/Mississippi State University Developed 3-D Aeroelastic Computer Code). Unsteady pressure predictions for the turbine test case were used to evaluate the forced response prediction capabilities of each of the three aeroelastic codes. Additionally, one of the fan flutter cases was evaluated using TURBO-AE. The UNSFLO and FREPS evaluation predictions showed good agreement with the experimental test data trends, but quantitative improvements are needed. UNSFLO over-predicted turbine blade response reductions, while FREPS under-predicted them. The inviscid TURBO-AE turbine analysis predicted no discernible blade response reduction, indicating the necessity of including viscous effects for this test case. For the TURBO-AE fan blisk test case, significant effort was expended getting the viscous version of the code to give converged steady flow solutions for the transonic flow conditions. Once converged, the steady solutions provided an excellent match with test data and the calibrated DAWES (AlliedSignal 3-D Viscous Steady Flow CFD Solver). However, efforts expended establishing quality steady-state solutions prevented exercising the unsteady portion of the TURBO-AE code during the present program. AlliedSignal recommends that unsteady pressure measurement data be obtained for both test cases examined for use in aeroelastic code validation.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/CR-1999-209406 , NAS 1.26:209406 , ASE-21-10345 , E-11933
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  • 64
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    Forced Mixer Nozzle Optimization (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: Computational fluid dynamic (CFD) and computational acoustic analyses (CAA) were performed for a TFE731-40 compound nozzle, a TFE731-60 mixer nozzle and an Energy Efficient Engine (E(sup 3)) mixer nozzle for comparison with available data. The CFD analyses were performed with a three dimensional, Navier-Stokes solution of the flowfield on an unstructured grid using the RAMPANT program. The CAA analyses were performed with the NASA Glenn MGB program using a structured grid. A successful aerodynamic solution for the TFE731-40 compound nozzle operating statically was obtained, simulating an engine operating on a test stand. Analysis of the CFD results of the TFE731-40 with the MGB program produced predicted sound power levels that agree quite well with the measured data front full-scale static engine tests. Comparison of the predicted sound pressure with the data show good agreement near the jet axis, but the noise levels are overpredicted at angles closer to the inlet. The predicted sound power level for the TFE731-60 did not agree as well with measured static engine data as the TFE731-40. Although a reduction in the predicted noise level due to the mixed flow was observed, the reduction was not as significant as the measured data. The analysis of the V2 mixer from the E(sup 3) study showed that peak temperatures predicted in the mixer exit flowfield were within 5 percent of the values measured by the exit probes. The noise predictions of the V2 mixer nozzle tended to be 3-5 dB higher in peak noise level than the measurements. In addition, the maximum frequency of the noise was also overpredicted. An analysis of the 3 candidate mixer nozzle configurations demonstrated the feasibility of using centerbody lobes and porosity to improve mixing efficiency. A final configuration was designed with a predicted thermal mixing efficiency that was 5 percent higher than the 3 candidate mixers. The results of the MGB noise calculations show that the final design will exceed the design goal of a 3 dB reduction in noise as compared to the baseline TFE731-40.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/CR-1999-209160 , E-11723 , NAS 1.26:209160
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    An Evaluation of Aircraft Emissions Inventory Methodology by Comparisons with Reported Airline Data (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: This report provides results of work done to evaluate the calculation methodology used in generating aircraft emissions inventories. Results from the inventory calculation methodology are compared to actual fuel consumption data. Results are also presented that show the sensitivity of calculated emissions to aircraft payload factors. Comparisons of departures made, ground track miles flown and total fuel consumed by selected air carriers were made between U.S. Dept. of Transportation (DOT) Form 41 data reported for 1992 and results of simplified aircraft emissions inventory calculations. These comparisons provide an indication of the magnitude of error that may be present in aircraft emissions inventories. To determine some of the factors responsible for the errors quantified in the DOT Form 41 analysis, a comparative study of in-flight fuel flow data for a specific operator's 747-400 fleet was conducted. Fuel consumption differences between the studied aircraft and the inventory calculation results may be attributable to several factors. Among these are longer flight times, greater actual aircraft weight and performance deterioration effects for the in-service aircraft. Results of a parametric study on the variation in fuel use and NOx emissions as a function of aircraft payload for different aircraft types are also presented.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/CR-1999-209480 , Rept-99B00077 , NAS 1.26:209480
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    TADS--A CFD-Based Turbomachinery Analysis and Design System with GUI: User's Manual (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: The primary objective of this study was the development of a Computational Fluid Dynamics (CFD) based turbomachinery airfoil analysis and design system, controlled by a Graphical User Interface (GUI). The computer codes resulting from this effort are referred to as TADS (Turbomachinery Analysis and Design System). This document is intended to serve as a User's Manual for the computer programs which comprise the TADS system, developed under Task 18 of NASA Contract NAS3-27350, ADPAC System Coupling to Blade Analysis & Design System GUI and Task 10 of NASA Contract NAS3-27394, ADPAC System Coupling to Blade Analysis & Design System GUI, Phase II-Loss, Design and, Multi-stage Analysis. TADS couples a throughflow solver (ADPAC) with a quasi-3D blade-to-blade solver (RVCQ3D) in an interactive package. Throughflow analysis and design capability was developed in ADPAC through the addition of blade force and blockage terms to the governing equations. A GUI was developed to simplify user input and automate the many tasks required to perform turbomachinery analysis and design. The coupling of the various programs was done in such a way that alternative solvers or grid generators could be easily incorporated into the TADS framework. Results of aerodynamic calculations using the TADS system are presented for a highly loaded fan, a compressor stator, a low speed turbine blade and a transonic turbine vane.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/CR-1999-206604 , NAS 1.26:206604 , E-11117
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    Real-Time Optical Fuel-to-Air Ratio Sensor for Gas Turbine Combustors (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: The measurement of the temporal distribution of fuel in gas turbine combustors is important in considering pollution, combustion efficiency and combustor dynamics and acoustics. Much of the previous work in measuring fuel distributions in gas turbine combustors has focused on the spatial aspect of the distribution. The temporal aspect however, has often been overlooked, even though it is just as important. In part, this is due to the challenges of applying real-time diagnostic techniques in a high pressure and high temperature environment. A simple and low-cost instrument that non-intrusively measures the real-time fuel-to-air ratio (FAR) in a gas turbine combustor has been developed. The device uses a dual wavelength laser absorption technique to measure the concentration of most hydrocarbon fuels such as jet fuel, methane, propane, etc. The device can be configured to use fiber optics to measure the local FAR inside a high pressure test rig without the need for windows. Alternatively, the device can readily be used in test rigs that have existing windows without modifications. An initial application of this instrument was to obtain time-resolved measurements of the FAR in the premixer of a lean premixed prevaporized (LPP) combustor at inlet air pressures and temperatures as high as 17 atm at 800 K, with liquid JP-8 as the fuel. Results will be presented that quantitatively show the transient nature of the local FAR inside a LPP gas turbine combustor at actual operating conditions. The high speed (kHz) time resolution of this device, combined with a rugged fiber optic delivery system, should enable the realization of a flight capable active-feedback and control system for the abatement of noise and pollutant emissions in the future. Other applications that require an in-situ and time-resolved measurement of fuel vapor concentrations should also find this device to be of use.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-1999-209041 , NAS 1.15:209041 , E-11566
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    A One Dimensional, Time Dependent Inlet/Engine Numerical Simulation for Aircraft Propulsion Systems (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: The NASA Lewis Research Center (LeRC) and the Arnold Engineering Development Center (AEDC) have developed a closely coupled computer simulation system that provides a one dimensional, high frequency inlet/engine numerical simulation for aircraft propulsion systems. The simulation system, operating under the LeRC-developed Application Portable Parallel Library (APPL), closely coupled a supersonic inlet with a gas turbine engine. The supersonic inlet was modeled using the Large Perturbation Inlet (LAPIN) computer code, and the gas turbine engine was modeled using the Aerodynamic Turbine Engine Code (ATEC). Both LAPIN and ATEC provide a one dimensional, compressible, time dependent flow solution by solving the one dimensional Euler equations for the conservation of mass, momentum, and energy. Source terms are used to model features such as bleed flows, turbomachinery component characteristics, and inlet subsonic spillage while unstarted. High frequency events, such as compressor surge and inlet unstart, can be simulated with a high degree of fidelity. The simulation system was exercised using a supersonic inlet with sixty percent of the supersonic area contraction occurring internally, and a GE J85-13 turbojet engine.
    Keywords: Aircraft Propulsion and Power
    Type: Design Principles and Methods for Aircraft Gas Turbine Engines; 25-1 - 25-10; RTO-MP-8
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  • 69
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    Inlet Flow Characteristics During Rapid Maneuvers for an F/A-18A Airplane (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: The F404-GE-400 engine powered F/A-18A High Alpha Research Vehicle (HARV) was used to examine the characteristics of inlet airflow during rapid aircraft maneuvers. A study of the degree of similarity between inlet data obtained during rapid aircraft maneuvers and inlet data obtained at steady aerodynamic attitudes was conducted at the maximum engine airflow of approximately 145 Ibm/sec using a computer model that was generated from inlet data obtained during steady aerodynamic maneuvers. Results show that rapid-maneuver inlet recoveries agreed very well with the recoveries obtained at equivalent stabilized angle-of-attack conditions. The peak dynamic circumferential distortion values obtained during rapid maneuvers agreed within 0.01 units of distortion over the 10 - 38 degree angle of attack range with the values obtained during steady aerodynamic maneuvers while similar agreement was found for the peak dynamic radial distortion values up to 29 degrees angle-of-attack. Exceedences of the rapid-maneuver peak dynamic circumferential distortion values relative to the peak distortion model values at steady attitudes occurred only at low or negative angles of attack and were inconsequential from an engine-stability assessment point of view. The results of this study validate the current industry practice of testing at steady aerodynamic conditions to characterize inlet recovery and peak dynamic distortion levels.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-1999-206587 , H-2371 , NAS 1.15:206587
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  • 70
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    X-33/RLV Program Aerospike Engines (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: Substantial progress was made during the past year in support of the X-33/RLV program. X-33 activity was directed towards completing the remaining design work and building hardware to support test activities. RLV work focused on the nozzle ramp and powerpack technology tasks and on supporting vehicle configuration studies. On X-33, the design activity was completed to the detail level and the remainder of the drawings were released. Component fabrication and engine assembly activity was initiated, and the first two powerpacks and the GSE and STE needed to support powerpack testing were completed. Components fabrication is on track to support the first engine assembly schedule. Testing activity included powerpack testing and component development tests consisting of thrust cell single cell testing, CWI system spider testing, and EMA valve flow and vibration testing. Work performed for RLV was divided between engine system and technology development tasks. Engine system activity focused on developing the engine system configuration and supporting vehicle configuration studies. Also, engine requirements were developed, and engine performance analyses were conducted. In addition, processes were developed for implementing reliability, mass properties, and cost controls during design. Technology development efforts were divided between powerpack and nozzle ramp technology tasks. Powerpack technology activities were directed towards the development of a prototype powerpack and a ceramic turbine technology demonstrator (CTTD) test article which will allow testing of ceramic turbines and a close-coupled gas generator design. Nozzle technology efforts were focused on the selection of a composite nozzle supplier and on the fabrication and test of composite nozzle coupons.
    Keywords: Aircraft Propulsion and Power
    Type: RD99-251 , X-33 Flight Operations Center
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  • 71
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    Factors Affecting Inlet-Engine Compatibility During Aircraft Departures at High Angle of Attack for an F/A -18A Aircraft (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: The F404-GE-400 engine powered F/A- 18A High Alpha Research Vehicle (HARV) was used to examine the quality of inlet airflow during departed flight maneuvers, that is, during flight outside the normal maneuvering envelope where control surfaces have little or no effectiveness. A series of six nose-left and six nose-right departures were initiated at Mach numbers between 0.3 and 0.4 at an altitude of 35 kft. The yaw rates at departure recovery were in the range of 40 to 90 degrees per second. Engine surges were encountered during three of the nose-left and one of the nose-right departures. Time-variant inlet-total-pressure distortion levels at the engine face were determined to not significantly exceed those measured at maximum angle-of-attack and - sideslip maneuvers during controlled flight. Surges as a result of inlet distortion levels were anticipated to initiate in the fan. Analysis revealed that the surges initiated in the compressor and were the result of a combination of high levels of inlet distortion and rapid changes in aircraft motion. These rapid changes in aircraft motion are indicative of a combination of engine mount and gyroscopic loads being applied to the engine structure that impact the aerodynamic stability of the compressor through changes in the rotor-to-case clearances.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-1999-206572 , H-2327 , NAS 1.15:206572
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  • 72
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    Jet Nozzle Having Centerbody for Enhanced Exit Area Mixing (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: A nozzle arrangement includes a nozzle and a centerbody. The longitudinal axis of the centerbody is coaxially aligned with the nozzle. The centerbody has a free end portion shaped to create vortices in exhaust exiting the exit area. The vortices enhance mixing action in the exhaust and reduce exhaust noise while augmenting thrust.
    Keywords: Aircraft Propulsion and Power
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  • 73
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    Aero-Thermo-Structural Design Optimization of Internally Cooled Turbine Blades (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: A set of robust and computationally affordable inverse shape design and automatic constrained optimization tools have been developed for the improved performance of internally cooled gas turbine blades. The design methods are applicable to the aerodynamics, heat transfer, and thermoelasticity aspects of the turbine blade. Maximum use of the existing proven disciplinary analysis codes is possible with this design approach. Preliminary computational results demonstrate possibilities to design blades with minimized total pressure loss and maximized aerodynamic loading. At the same time, these blades are capable of sustaining significantly higher inlet hot gas temperatures while requiring remarkably lower coolant mass flow rates. These results suggest that it is possible to design internally cooled turbine blades that will cost less to manufacture, will have longer life span, and will perform as good, if not better than, film cooled turbine blades.
    Keywords: Aircraft Propulsion and Power
    Type: Design Principles and Methods for Aircraft Gas Turbine Engines; 35-1 - 35-12; RTO-MP-8
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  • 74
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    Rotating Pip Detection and Stall Warning in High-Speed Compressors Using Structure Function (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: A statistic for both rotating pip and incipient stall detection, called Structure Function is introduced for use in high speed research compressor environments. Experimental studies on stall inception processes have long observed two types of pre-stall compressor activity. Presently there exist methods for indicating modal stall precursive events in the compressor. This is a first application of a new method to detect rotating pip activity prior to stall in research compressors. The algorithm requires a very short sample of data to distinguish pip activity prior to stall, and thus may be used in a real time application. Additionally, this Structure Function algorithm is also used as a single sensor stall warning method under a variety of operating conditions, including clean inlet conditions, radially and circumferentially distorted inlet conditions, and in examples of steady air injection along the casing, and controlled air injection conditions. Structure Function provides a potential advantage over linear spectral techniques and wavelet algorithms for stall detection due to the simplicity of the algorithm and because it does not rely on a priori knowledge of frequency content.
    Keywords: Aircraft Propulsion and Power
    Type: Design Principles and Methods for Aircraft Gas Turbine Engines; 29-1 - 29-7; RTO-MP-8
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  • 75
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    Application of a Flip-Flop Nozzle on Plume Mixing Enhancement (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: Mach wave radiation is a major source of noise in high speed jets. It is created by turbulent eddies which travel at supersonic speed within the shear layer of the jet. Downstream of the potential core, the convection speed of the eddies decays and noise production is reduced. Once the convection speeds drops below the speed of sound, eddy Mach wave radiation ceases. Mach wave radiation may be reduced by shortening the core length of the jet. This requires a faster growth of the shear layer, i.e. enhanced mixing in the jet. We investigated the possibility of mixing enhancement by the excitation of the instability waves in a supersonic rectangular jet.
    Keywords: Aircraft Propulsion and Power
    Type: First NASA/Industry High Speed Research Program Nozzle Symposium; 13-1 - 13-15; NASA/CP-1999-209423
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  • 76
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    The Effect of Air Preheat at Atmospheric Pressure on the Formation of NO(x) in the Quick-Mix Sections of an Axially Staged Combustor (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: The Rich-burn/Quick-mix/Lean-burn (RQL) combustor concept has been proposed to minimize the formation of nitrogen oxides (NO(x)) in gas turbine systems. The success of this combustor strategy is dependent upon the efficiency of the mixing section bridging the fuel-rich and fuel-lean stages. Note that although these results were obtained from an experiment designed to study an RQL mixer, the link between mixing and NOx signatures is considerably broader than this application, in that the need to understand this link exists in most advanced combustors. The experiment reported herein was designed to study the effects of inlet air temperature on NO(x) formation in a mixing section. The results indicate that NO(x) emission is increased for all preheated cases compared to non-preheated cases. When comparing the various mixing modules, the affect of jet penetration is important, as this determines where NO(x) concentrations peak, and affects overall NO(x) production. Although jet air comprises 70 percent of the total airflow, the impact that jet air preheat has on overall NO(x) emissions is small compared to preheating both main and jet air flow.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-1999-209431 , E-11872 , NAS 1.15:209431
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    Small Engine Technology (SET) - Task 14 Axisymmetric Engine Simulation Environment (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: As part of the NPSS (Numerical Propulsion Simulation System) project, NASA Lewis has a goal of developing an U.S. industry standard for an axisymmetric engine simulation environment. In this program, AlliedSignal Engines (AE) contributed to this goal by evaluating the ENG20 software and developing support tools. ENG20 is a NASA developed axisymmetric engine simulation tool. The project was divided into six subtasks which are summarized below: Evaluate the capabilities of the ENG20 code using an existing test case to see how this procedure can capture the component interactions for a full engine. Link AE's compressor and turbine axisymmetric streamline curvature codes (UD0300M and TAPS) with ENG20, which will provide the necessary boundary conditions for an ENG20 engine simulation. Evaluate GE's Global Data System (GDS), attempt to use GDS to do the linking of codes described in Subtask 2 above. Use a turbofan engine test case to evaluate various aspects of the system, including the linkage of UD0300M and TAPS with ENG20 and the GE data storage system. Also, compare the solution results with cycle deck results, axisymmetric solutions (UD0300M and TAPS), and test data to determine the accuracy of the solution. Evaluate the order of accuracy and the convergence time for the solution. Provide a monthly status report and a final formal report documenting AE's evaluation of ENG20. Provide the developed interfaces that link UD0300M and TAPS with ENG20, to NASA. The interface that links UD0300M with ENG20 will be compatible with the industr,, version of UD0300M.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/CR-1999-208673 , NAS 1.26:208673 , E-11401 , Rept-21-10296
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    Design of a Low Speed Fan Stage for Noise Suppression (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: This report describes the design of a low tip speed, moderate pressure rise fan stage for demonstration of noise reduction concepts. The fan rotor is a fixed-pitch configuration delivering a design pressure ratio of 1.378 at a specific flow of 43.1 lbm/sec/sq ft. Four exit stator configurations were provided to demonstrate the effectiveness of circumferential and axial sweep in reducing rotor-stator interaction tone noise. The fan stage design was combined with an axisymmetric inlet, conical convergent nozzle, and nacelle to form a powered fan-nacelle subscale model. This model has a 22-inch cylindrical flow path and employs a rotor with a 0.30 hub-to-tip radius ratio. The design is fully compatible with an existing NASA force balance and rig drive system. The stage aerodynamic and structural design is described in detail. Three-dimensional (3-D) computational fluid dynamics (CFD) tools were used to define optimum airfoil sections for both the rotor and stators. A fan noise predictive system developed by Pratt & Whitney under contract to NASA was used to determine the acoustic characteristics of the various stator configurations. Parameters varied included rotor-to-stator spacing and vane leading edge sweep. The structural analysis of the rotor and stator are described herein. An integral blade and disk configuration was selected for the rotor. Analysis confirmed adequate low cycle fatigue life, vibratory endurance strength, and aeroelastic suitability. A unique load carrying stator arrangement was selected to minimize generation of tonal noise due to sources other than rotor-stator interaction. Analysis of all static structural components demonstrated adequate strength, fatigue life, and vibratory characteristics.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/CR-1999-208682 , Allison-EDR-17923 , E-11423 , NAS 1.26:208682
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    Noise Certification Predictions for FJX-2-Powered Aircraft Using Analytic Methods (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: Williams International Co. is currently developing the 700-pound thrust class FJX-2 turbofan engine for the general Aviation Propulsion Program's Turbine Engine Element. As part of the 1996 NASA-Williams cooperative working agreement, NASA agreed to analytically calculate the noise certification levels of the FJX-2-powered V-Jet II test bed aircraft. Although the V-Jet II is a demonstration aircraft that is unlikely to be produced and certified, the noise results presented here may be considered to be representative of the noise levels of small, general aviation jet aircraft that the FJX-2 would power. A single engine variant of the V-Jet II, the V-Jet I concept airplane, is also considered. Reported in this paper are the analytically predicted FJX-2/V-Jet noise levels appropriate for Federal Aviation Regulation certification. Also reported are FJX-2/V-Jet noise levels using noise metrics appropriate for the propeller-driven aircraft that will be its major market competition, as well as a sensitivity analysis of the certification noise levels to major system uncertainties.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-1999-208908 , NAS 1.15:208908 , E-11522
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    3D Multistage Simulation of Each Component of the GE90 Turbofan Engine (1999)
    In:  Other Sources
    Details
    Publication Date: 2019-07-17
    Description: A 3D multistage simulation of each component of the GE90 Turbofan engine has been made. This includes 49 blade rows. A coupled simulation of all blade rows will be made very soon. The simulation is running using two levels of parallelism. The first level is on a blade row basis with information shared using files. The second level is using a grid domain decomposition with information shared using MPI. Timings will be shown for running on the SP2, an SGI Origin and a distributed system of HP workstations. On the HP workstations, the CHIMP version of MPI is used, with queuing supplied by LSF (Load Sharing Facility). A script-based control system is used to ensure reliability. An MPEG movie illustrating the flow simulation of the engine has been created using PV3, a parallel visualization library created by Bob Haimes of MIT. PVM is used to create a virtual machine from 10 HP workstations and display on an SGI workstation. A representative component simulation will be compared to rig data to demonstrate its usefulness in turbomachinery design and analysis.
    Keywords: Aircraft Propulsion and Power
    Type: HPCCP/CAS Workshop Proceedings 1998; 87; NASA/CP-1999-208757
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    Development of Hub Corner Stall and Its Influence on the Performance of Axial Compressor Blade Rows (1999)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: A detailed investigation has been performed to study hub corner stall phenomena in compressor blade rows. Three-dimensional flows in a subsonic annular compressor stator and in a transonic compressor rotor have been analyzed numerically by solving the Reynolds-averaged Navier-Stokes equations. The numerical results and the existing experimental data are interrogated to understand the mechanism of compressor hub comer stall. Both the measurements and the numerical solutions for the stator indicate that a strong twister-like vortex is formed near the rear part of the blade suction surface. Low-momentum fluid inside the hub boundary layer is transported toward the suction side of the blade by this vortex. On the blade suction surface near the hub, this vortex forces fluid to move against the main flow direction and a limiting stream surface is formed near the hub. The formation of this vortex is the main mechanism of hub corner stall. When the aerodynamic loading is increased, the vortex initiates further upstream, which results in a larger corner stall region. For the transonic compressor rotor studied in this paper, the numerical solution indicates that a mild hub corner stall exists at 100 percent rotor speed. The hub corner stall, however, disappears at the reduced blade loading, which occurs at 60 percent rotor design speed. The present study demonstrates that hub comer stall is caused by a three-dimensional vortex system and that it does not seem to be correlated with a simple diffusion factor for the blade row.
    Keywords: Aircraft Propulsion and Power
    Type: ASME-97-GT-42 , 42nd International Gas Turbine and Aeroengine Congress and Exhibition; Jun 02, 1997 - Jun 05, 1997; Orlando, FL; United States|Journal of Turbomachinery; 121; 67-77
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    Notes on Menippus and Issikia from Sumatra and Java, Indonesia (Coleoptera: Chrysomelidae: Galerucinae) (1999)
    In:  Zoologische Mededelingen (00240672) vol.73, 1-11 (1999) p.187
    Details
    Publication Date: 2007-01-23
    Description: Menippus philippinensis Jacoby, 1894, is reported from Java, and Issikia clarki (Jacoby, 1884) comb. nov., from Sumatra.
    Keywords: Coleoptera ; Chrysomelidae ; Galerucinae ; Menippus ; Issikia ; Issikia clarki ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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    Nieuwe en oude vindplaatsen van de roofvlieg Machimus cowini in Nederland (Diptera: Asilidae) (1999)
    In:  Nederlandse Faunistische Mededelingen (01692453) vol.9 (1999) p.143
    Details
    Publication Date: 2007-01-10
    Description: New and old records of the robberfly Machimus cowini in the Netherlands (Diptera: Asilidae) Until recently, Machimus cowini (Hobby, 1943) was known from just one record in the Netherlands. An examination of Dutch specimens of the similar M. cingulatus revealed specimens of M. cowini from five new localities. The records are concentrated on the island Ameland and along the rivers Waal and Maas. On Ameland, M. cowini probably occurs in coastal dunes. Near Nijmegen the species was found in grassy vegetation on floodplains and on riverdunes near the river.
    Keywords: Insecta ; Diptera ; Asilidae ; Machimus cowini ; Nederland ; Verspreiding ; Biotopen ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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    The Palaearctic species of the genus Diachasmimorpha Viereck (Hymenoptera: Braconidae: Opiinae) (1999)
    In:  Zoologische Mededelingen (00240672) vol.73, 1-11 (1999) p.1
    Details
    Publication Date: 2007-01-23
    Description: Two new species of the genus Diachasmimorpha Viereck, 1913 (Braconidae: Opiinae) are described: D. feijeni spec. nov. from Bhutan (reared from Bactrocera minax (Enderlein) (Diptera: Tephritidae) in fruits of Citrus reticulata Blanco (mandarin)) and D. budrysi spec. nov. from Far East Russia. A key to the Palaearctic species is added, including two similar species (Fopius alternatae (Tobias, 1977), and F. myolejae (Tobias, 1977)).
    Keywords: Hymenoptera ; Braconidae ; Opiinae ; Diachasmimorpha ; Palaearctic ; Bhutan ; Russia ; key ; Diptera ; Citrus reticulata ; Bactrocera minax ; Tephritidae ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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    Pemphredon montana, een nieuwe graafwesp voor Nederland (Hymenoptera: Specidae) (1999)
    In:  Nederlandse Faunistische Mededelingen (01692453) vol.9 (1999) p.142
    Details
    Publication Date: 2007-01-10
    Description: Pemphredon montana, new to The Netherlands (Hymenoptera: Sphecidae) In 1998 Pemphredon montana Dahlbom, 1845 was recorded for the first time in the Netherlands. The species was found nesting in the insulating material of a caravan in the northernmost part of the province of Overijssel.
    Keywords: Insecta ; Hymenoptera ; Sphecidae ; Crabronidae ; Pemphredon montana ; Nederland ; Verspreiding ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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    Porcellium conspersum, een in Nederland zeer zeldzame landpissebed van vochtige bossen (Crustacea: Isopoda: Oniscoidea) (1999)
    In:  Nederlandse Faunistische Mededelingen (01692453) vol.9 (1999) p.140
    Details
    Publication Date: 2007-01-10
    Description: The influence of recent inundations on the distribution pattern of the isopod Eluma purpurascens in the province of Zeeland (Crustacea: Isopoda: Oniscoidea) Small scale mapping of Eluma purpurascens Budde-Lund, 1885 in the province of Zeeland revealed a remarkable distribution pattern. The species proved to be absent in parts which have been inundated during and after the second world war. This study shows that for the interpretation of distribution patterns the history of the study area should be considered.
    Keywords: Arthropoda ; Crustacea ; Isopoda ; Oniscoidea ; Nederland ; Verspreiding ; Biotopen ; Herkenning ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • 87
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    Faunistiek en ecologie van het zweefvliegengenus Epistrophe in Nederland (Diptera: Syrphidae) (1999)
    In:  Nederlandse Faunistische Mededelingen (01692453) vol.8 (1999) p.33
    Details
    Publication Date: 2007-01-09
    Description: Faunistics and ecology of the syrphid genus Epistrophe in The Netherlands (Diptera: Syrphidae) Ten species of Epistrophe have been found in the Netherlands, two of which, E. cryptica and E. similis, are recorded here for the first time. The distribution, changes in distribution and ecology of the species were investigated and are illustrated by distribution maps and diagrams of the flight period. In all species, except E. eligans, females were observed more than males. Furthermore, females seem to be active later in the season than males. It is discussed that this is probably caused by the differences in behaviour between the males of the species.
    Keywords: Insecta ; Diptera ; Syrphidae ; Epistrophe ; Fenologie ; Verspreiding ; Biologie ; Nederland ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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    De sneeuwspringer Boreus hyemalis in Nederland (Mecoptera: Boreidae) (1999)
    In:  Nederlandse Faunistische Mededelingen (01692453) vol.8 (1999) p.1
    Details
    Publication Date: 2007-01-26
    Description: Until recently Boreus hyemalis was considered to be a rare species in The Netherlands. It was only known from a few localities in The Netherlands in the provinces of Noord-Holland, Zuid- Holland, Utrecht, Gelderland and Drenthe. The last few years many new populations have been discovered. In this paper the first records for the provinces of Limburg, Noord-Brabant and Overijssel are presented. The species seems to prefer scarcely vegetated patches in sanddunes, dominated by greyhair grass Corynephorus canescens and the moss Polytrichum piliferum. It proved to be relatively easy to find, when the right places were searched in the right period (October until February).
    Keywords: Insecta ; Mecoptera ; Boreidae ; Boreus hyemalis ; Sneeuwspringer ; Verspreiding ; Nederland ; Biotopen ; Biologie ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • 89
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    Unknown
    The genus Bryotropha in the Netherlands (Lepidoptera: Gelechiidae) (1999)
    In:  Nederlandse Faunistische Mededelingen (01692453) vol.9 (1999) p.79
    Details
    Publication Date: 2007-01-10
    Description: Het genus Bryotropha in Nederland (Lepidoptera: Gelechiidae) Het genus Bryotropha staat bekend als een notoir lastig geslacht van kleine bruine motjes. Die moeilijkheid komt door de variatie, maar vooral ook door gebrek aan bruikbare beschrijvingen. Met dit artikel zijn de negen Nederlandse soorten te determineren. Vanwege het gebrek aan determinatieliteratuur in heel Europa is het in het Engels geschreven. Behalve de maar één keer waargenomen B. domestica, zijn de meeste soorten vrij gewone verschijningen in ons land, zoals uit de kaarten blijkt.
    Keywords: Insecten ; Lepidoptera ; Gelechiidae ; Verspreiding ; Nederland ; Fenologie ; Waardplanten ; Biotopen ; Determinatiesleutel ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • 90
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    Unknown
    De valkruidmineervlinder Digitivalva arnicella in Nederland: herontdekking en behoud (Lepidoptera: Plutellidae: Acrolepiinae) (1999)
    In:  Nederlandse Faunistische Mededelingen (01692453) vol.9 (1999) p.15
    Details
    Publication Date: 2007-08-06
    Description: The occurrence of Digitivalva arnicella in the Netherlands: rediscovery and conservation (Lepidoptera: Plutellidae: Acrolepiinae) Digitivalva arnicella (Heyden, 1863), previously only known from two localities before 1902, has been rediscovered in eight localities in the northern part of the Netherlands (province of Drenthe) on its host Arnica montana. On the basis of leafmines, found in old herbarium collections, it can be concluded that the species was once widespread within the range of its host in the northern and eastern parts of the Netherlands and has apparently been overlooked by entomologists since. D. arnicella is a much endangered species in the Netherlands, because of the dramatic decline of its host. Two of the eight discovered populations have been lost since their discovery in the first half of the 1990’s. Systematics and life history of the species are described and illustrated, the distribution is mapped and advise for management of its sites are given. The current management of some populations of Arnica, by mowing the site completely in August, is disastrous for the young caterpillars, mining the leaves.
    Keywords: Acrolepiinae ; Plutellidae ; Yponomeutoidea ; Digitivalva ; Netherlands ; conservation ; Arnica ; Digitivalva arnicella ( Plutellidae- ) ; Habitat management ; Endangered status ; effect of food plant shortage ; conservation proposals ; Food plants ; Arnica montana ; effect on decline to endangered status ; Decline-to-endangered-status ; influences-and-conservation ; Netherlands ; Distribution ; population dynamics and conservation ; endangered species ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • 91
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    Unknown
    De boskrekel Nemobius sylvestris in de duinen bij Bergen (Noord-Holland) (Orthoptera) (1999)
    In:  Nederlandse Faunistische Mededelingen (01692453) vol.8 (1999) p.91-93
    Details
    Publication Date: 2007-01-09
    Description: Nemobius sylvestris in the dunes near Bergen (Orthoptera) A large population of Nemobius sylvestris (Bosc, 1792) has been found in the dunes near Bergen (Noord-Holland), 60 km northwest of the nearest known site in the Gooi-area. This discovery sheds new light on a specimen from Bergen found in a collection, which was thought to be mislabelled.
    Keywords: Insecta ; Orthoptera ; Gryllidae ; Nemobius sylvestris ; Nederland ; Verspreiding ; Biotopen ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 92
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    Unknown
    Interessante libellenwaarnemingen in 1998 (Odonata) (1999)
    In:  Nederlandse Faunistische Mededelingen (01692453) vol.8 (1999) p.85
    Details
    Publication Date: 2007-01-09
    Description: Interesting new records of Odonata in the Netherlands in 1998 A survey of the most interesting observations on Dutch Odonata is presented. During the Odonata Recording Scheme many new records of rare species have become available. Gomphus flavipes, G. vulgatissimus, Anax parthenope, Sympetrum pedemontanum and S. depressiusculum seem to become more common. The status of some threatened species is elucidated: Calopteryx virgo, Sympecma paedisca, Coenagrion hastulatum and Cordulegaster boltonii.
    Keywords: Insecta ; Odonata ; Verspreiding ; Nederland ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 93
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    Unknown
    The West Palaearctic species of the subfamily Paxylommatinae (Hymenoptera: Ichneumonidae), with special reference to the genus Hybrizon Fallén (1999)
    In:  Zoologische Mededelingen (00240672) vol.73, 1-11 (1999) p.11
    Details
    Publication Date: 2007-01-23
    Description: The West Palaearctic species of the subfamily Paxylommatinae are reviewed and the species of the genus Hybrizon Fallén, 1813, from the Palaearctic region are keyed. Hybrizon juncoi (Ceballos, 1957) is recognized as a valid species, a neotype is designated for Hybrizon latebricola Nees, 1834, and a lectotype is designated for Plancus apicalis Curtis, 1833. Paxylomma grandis Rudow, 1883, Ogkosoma schwarzi Haupt, 1913, and Eurypterna arakawae Matsumura, 1918, are new junior synonyms of Eurypterna cremieri (de Romand, 1838).
    Keywords: Ichneumonidae ; Paxylommatinae ; Hybrizon ; Ghilaromma ; Eurypterna ; keys ; distribution ; Palaearctic ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 94
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    Unknown
    The genus Scrobipalpa in the Netherlands (Lepidoptera: Gelechiidae) (1999)
    In:  Nederlandse Faunistische Mededelingen (01692453) vol.9 (1999) p.29
    Details
    Publication Date: 2007-01-10
    Description: Het genus Scrobipalpa in Nederland (Lepidoptera: Gelechiidae) Scrobipalpa is een geslacht van kleine, lastig uit elkaar te houden motjes. In heel Europa zijn ongeveer 70 soorten bekend. Doorgaans zijn de vleugels bruin- of grijsachtig met een tekening van stippels en strepen die bovendien erg kan variëren. Hierdoor kunnen de individuele soorten vaak moeilijk herkend worden. Aan de hand van de genitaliën kunnen soorten wel allemaal gedetermineerd worden. Omdat de literatuur over deze groep niet erg toegankelijk is en bestaande beschrijvingen soms erg onvolledig zijn, wordt dit artikel in het Engels geschreven. Met dit artikel zijn de elf Nederlandse soorten te determineren. De meeste hiervan zijn min of meer gebonden aan de kust. Van alle soorten worden naast beschrijvingen van de vleugeltekening en de genitaliën, ook de verspreiding, de biologie en de ecologie gegeven.
    Keywords: Insecta ; Lepidoptera ; Scrobipalpa ; Verspreiding ; Biotopen ; Fenologie ; Herkenning ; Determinatiesleutel ; Waardplanten ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 95
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    Unknown
    Cheilosia caerulescens in Nederland in 1998 (Diptera: Syprhidae) (1999)
    In:  Nederlandse Faunistische Mededelingen (01692453) vol.8 (1999) p.93
    Details
    Publication Date: 2007-01-09
    Description: New records of Cheilosia caerulescens in the Netherlands (Diptera: Syrphidae) Cheilosia caerulescens is a rare hoverfly in The Netherlands. Until 1998 only four records were known, the first in 1986. In 1998 the species was found on three new and one old locality. The record from Heemstede (province of Noord-Holland) is among the northernmost in the European distribution of this species. Three of the four records originate from gardens.
    Keywords: Insecta ; Diptera ; Syrphidae ; Cheilosia caerulescens ; Nederland ; Verspreiding ; Biotopen ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 96
    facet.materialart.
    Unknown
    Dansmuggen in natuurontwikkelingsgebieden (Chironomidae) (1999)
    In:  Nederlandse Faunistische Mededelingen (01692453) vol.8 (1999) p.89
    Details
    Publication Date: 2007-01-09
    Description: Chironomidae in newly created nature reserves In a newly created nature reserve near Eindhoven many interesting species of Chironomidae were found. Several new species to the Dutch fauna were identified and one species (of the genus Neozavrelia) proved to be new to science. The fauna of these young habitats is poorly known, but proves to be very interesting.
    Keywords: Insecta ; Chironomidae ; Verspreiding ; Biotopen ; Nederland ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 97
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    Four new species of Pteromalus Swederus (Hymenoptera: Chalcidoidea: Pteromalidae) and redescriptions of three other species (1999)
    In:  Zoologische Mededelingen (00240672) vol.73, 1-11 (1999) p.165
    Details
    Publication Date: 2007-01-23
    Description: A key to the European species of the Pteromalus altus group is presented. The relationship between this group and species of the genus Euphorbia (Euphorbiaceae) is confirmed. One new species: P. villosae, associated with Euphorbia villosa Waldst. & Kit.is presented. Two new species of the albipennis group: Pteromalus almeriensis and P. costulata are presented. In addition one species of the P. vibulenus group: P. tethys is added. Information on P. sylveni Hedqvist, P. osmiae Hedqvist and P. discors Graham is given.
    Keywords: Chalcidoidea ; Pteromalidae ; Pteromalus ; new species ; redescriptions ; Spain ; Portugal ; France ; Greece ; Euphorbia ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 98
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    Unknown
    The Egyptian species of Encarsia (Hymenoptera: Aphelinidae): a preliminary review (1999)
    In:  Zoologische Mededelingen (00240672) vol.73, 1-10 (1999) p.131
    Details
    Publication Date: 2007-01-23
    Description: The species of Encarsia Foerster (Hymenoptera: Aphelinidae) known from Egypt are revised. A total of 14 species are treated, including one new species. E. indifferentis Mercet, 1929, is synonymised with E. inaron (Walker, 1839). All species are fully described or diagnosed, and illustrated. Host records, and species-distributions outside Egypt, are given.
    Keywords: Egypt ; Encarsia ; Aleyrodidae ; Aphelinidae ; Diaspididae ; parasitoids ; biological control ; natural enemies ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 99
    facet.materialart.
    Unknown
    Bijzondere kevervondsten in Nederland (Coleoptera: Staphylinidae, Nitidulidae, Dermestidae) (1999)
    In:  Nederlandse Faunistische Mededelingen (01692453) vol.9 (1999) p.133
    Details
    Publication Date: 2007-01-10
    Description: Interesting records of beetles in The Netherlands (Coleoptera: Staphylinidae, Nitidulidae, Dermestidae) Tachyporus quadriscopulatus Pandellé, 1869 has been recorded for the second time in the Netherlands at Arcen and Velden, province of Limburg. After 27 years, a third record of Carpophilus marginellus Motschulsky, 1858 can be reported from St. Geertruid, in the southern part of the province of Limburg. One specimen was found outdoors, in a wood. One specimen of Anthrenocerus australis Hope, 1843 was also found outdoors, in Oost- Maarland also in southern Limburg, sitting on a flower in a meadow.
    Keywords: Insecta ; Coleoptera ; Staphylinidae ; Nitidulidae ; Dermestidae ; Nederland ; Verspreiding ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 100
    facet.materialart.
    Unknown
    Dagvlinders in 1998: nog steeds onder druk (Lepidoptera: Rhopalocera) (1999)
    In:  Nederlandse Faunistische Mededelingen (01692453) vol.9 (1999) p.127
    Details
    Publication Date: 2007-01-10
    Description: Butterflies in the Netherlands still under pressure (Lepidoptera: Rhopalocera) New information on the Dutch Rhopalocera fauna since the distribution atlas of Tax (1989) is presented. Coenonympha pamphilus was common in large parts of the Netherlands, but has declined dramatically. C. arcania is now formally extinct in our country. An extensive research showed that Maculinea alcon ericae has dissappeared from many sites. Furthermore the smallest of the two remaining populations of Heteropterus morpheus seems to have gone extinct. On the other hand, Callophrys rubi, has colonized new territory. Lampidus boeticus, was observed once as an adult and once a caterpillar was found between snow peas from Egypt. Colias croceus was very abundant in 1998. The reintroductions of Maculinea teleius and M. nausithous in 1990 appear to have been successful.
    Keywords: Insecta ; Lepidoptera ; Rhopalocera ; Verspreiding ; Bedreiging ; 42.75
    Repository Name: National Museum of Natural History, Netherlands
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