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  • Other Sources  (199)
  • AIRCRAFT PROPULSION AND POWER  (199)
  • 1980-1984  (199)
  • 1950-1954
  • 1925-1929
  • 1983  (199)
  • 1
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    Identification of multivariable high performance turbofan engine dynamics from closed loop data (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The multivariable instrumental variable/approximate maximum likelihood (IV/AML) method of recursive time-series analysis is used to identify the multivariable (four inputs-three outputs) dynamics of the Pratt and Whitney F100 engine. A detailed nonlinear engine simulation is used to determine linear engine model structures and parameters at an operating point using open loop data. Also, the IV/AML method is used in a direct identification made to identify models from actual closed loop engine test data. Models identified from simulated and test data are compared to determine a final model structure and parameterization that can predict engine response for a wide class of inputs. The ability of the IV/AML algorithm to identify useful dynamic models from engine test data is assessed. Previously announced in STAR as N82-20339
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 2
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    Numerical analysis of a scramjet inlet flow field using the three-dimensional Navier-Stokes equations (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: A computer program has been developed to analyze supersonic combustion ramjet (scramjet) inlet flow fields. The program solves the three-dimensional Euler or Navier-Stokes equations in full conservation form by a well-known explicit, predictor-corrector technique. Turbulence is modeled by an algebraic eddy-viscosity model. Detailed laminar and turbulent flow results are presented for a symmetric wedge corner and a comparison is made with the available experimental results to allow assessment of the program. Results are then presented for an actual scramjet inlet configuration.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: APL Computational Methods for Ramjets; p 25-40
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  • 3
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    Numerical study of scramjet and ramjet flow fields (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Two computer programs have been developed to numerically calculate complex, two-dimensional flow fields in scramjets. The first program is written for inlet analysis whereas the second program is written primarily for combustor analysis. Both programs solve the full two-dimensional Navier-Stokes equations by a well-known explicit, predictor-corrector technique. Turbulence is modeled by an algebraic eddy-viscosity model. The combustor program also includes one or more species conservation equations to calculate mixing and reacting flows. The hydrogen/air chemistry in this program is modeled by a complete reaction model. The combustor program has been recently modified to analyze axisymmetric ramjet dump combustor flow field. Results from these computer programs are presented that predict the flow in several scramjet inlet configurations, two model scramjet engine configurations, and in a dump combustor simulator. Computed results are also compared with available experimental data to allow assessment of the programs.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: APL Computational Methods for Ramjets; p 9-24
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  • 4
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    JT9D performance deterioration results from a simulated aerodynamic load test (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Previously cited in issue 19, p. 3268, Accession no. A81-40963
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: (ISSN 0021-8669)
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  • 5
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    Combustion hot section technology (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The overall objective of the Turbine Engine Hot Section Technology Combustion Project is to develop and verify improved and more accurate analysis methods for increasing the ability to design with confidence the combustion system for advanced aircraft turbine engines. The analysis methods developed will be generically applicable to combustion systems and not restricted to one specific engine or manufacturer. This project's approach was to first assess and evaluate existing combustor aerothermal analysis models by means of a contracted effort initiated during FY 1982. This evaluation effort has assessed and quantified known models' strengths and deficiencies. During FY 1984 the Aerothermal Modeling Program, Phase 2 will be initiated, which is expected to have contracted model development efforts in the areas of improved numerical methods for turbulent viscous flows, flow interactions, and fuel spray flow foekd interactions. A Phase 3 effort is planned to address remaining model deficiencies. The primary inhouse effort in this area will be the determination of high pressure flame radiation characteristics in a full annular combustor. This experiment will be conducted in the NASA LeRC High Pressure Facility with the results compiled into a comprehensive flame radiation and liner heat flux model.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Turbine Eng. Hot Sect. Technol. (HOST); p 129-133
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  • 6
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    HOST structural analysis program overview (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Hot section components of aircraft gas turbine engines are subjected to severe thermal structural loading conditions, especially during the start up and take off portions of the engine cycle. The most severe and damaging stresses and strains are those induced by the steep thermal gradients induced during the start up transient. These transient stresses and strains are also the most difficult to predict, in part because of the temperature gradients and distributions are not well known or readily predictable, and also because the cyclic elastic viscoplastic behavior of the materials at these extremes of temperature and strain are not well known or readily predictable. A broad spectrum of structures related technology programs is underway to address these deficiencies. One element of the structures program is developing improved time varying thermal mechanical load models for the entire engine mission cycle from start up to shutdown. Another major part of the program is the development of new and improved nonlinear 3-D finite elements and associated structural analysis programs, including the development of temporal elements with time dependent properties to account for creep effects in the materials and components.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Turbine Eng. Hot Sect. Technol. (HOST); p 153-158
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  • 7
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    Digital electronic engine control system - F-15 flight test (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: (Previously cited in issue 19, p. 3268, Accession no. A81-40912)
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 8
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    Subsonic/supersonic aeropropulsive characteristics of nonaxisymmetric nozzles installed on an F-18 model (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Previously cited in issue 19, p. 3266, Accession no. A81-40878
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: (ISSN 0021-8669)
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  • 9
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    Advanced electrical power system technology for the all electric aircraft (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The application of advanced electric power system technology to an all electric airplane results in an estimated reduction of the total takeoff gross weight of over 23,000 pounds for a large airplane. This will result in a 5 to 10 percent reduction in direct operating costs (DOC). Critical to this savings is the basic electrical power system component technology. These advanced electrical power components will provide a solid foundation for the materials, devices, circuits, and subsystems needed to satisfy the unique requirements of advanced all electric aircraft power systems. The program for the development of advanced electrical power component technology is described. The program is divided into five generic areas: semiconductor devices (transistors, thyristors, and diodes); conductors (materials and transmission lines); dielectrics; magnetic devices; and load management devices. Examples of progress in each of the five areas are discussed. Bipolar power transistors up to 1000 V at 100 A with a gain of 10 and a 0.5 microsec rise and fall time are presented. A class of semiconductor devices with a possibility of switching up to 100 kV is described. Solid state power controllers for load management at 120 to 1000 V and power levels to 25 kW were developed along with a 25 kW, 20 kHz transformer weighing only 3.2 kg. Previously announced in STAR as N83-24764
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 10
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    Development and operating characteristics of an advanced two-stage combustor (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Previously cited in issue 06, p. 813, Accession no. A82-17833
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: (ISSN 0146-0412)
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  • 11
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    Turbine blade nonlinear structural and life analysis (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 17, p. 2687, Accession no. A82-34981
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: (ISSN 0021-8669)
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  • 12
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    Design and development of a mixer compound exhaust system (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously cited in issue 22, p. 3815, Accession no. A81-45893)
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 13
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    Effect of variable guide vanes on the performance of a high-bypass turbofan engine (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: (Previously cited in issue 19, p. 3265, Accession no. A81-40842)
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 14
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    Turbofan engine blade pressure and acoustic radiation at simulated forward speed (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: (Previously cited in issue 07, p. 1010, Accession no. A81-20598)
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 15
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    NASA/General Electric Broad-Specification Fuels Combustion Technology Program - Phase I. (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Previously cited in issue 17, p. 2687, Accession no. A82-35000
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Journal of Energy (ISSN 0146-0412); 7; 508-517
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  • 16
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    End-wall boundary layer measurements in a two-stage fan (1983)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: Detailed flow measurements made in the casing boundary layer of a two-stage transonic fan are summarized. These measurements were taken at stations upstream of the fan, between all blade rows, and downstream of the last blade row. At the design tip speed of 429 m/sec the fan achieved a peak efficiency of 0.846 at a pressure ratio of 2.471. The boundary layer data were obtained at three weight flows at the design speed: one near choke flow, one near peak efficiency, and one near stall. Conventional boundary layer parameters were calculated from the data measured at each measuring station for each of the three flows. A classical two dimensional casing boundary layer was measured at the fan inlet and extended inward to approximately 15 percent of span. A highly three dimensional boundary layer was measured at the exit of each blade row and extended inward to approximately 10 percent of span. The steep radial gradient of axial velocity noted at the exit of the rotors was reduced substantially as the flow passed through the stators. This reduced gradient is attributed to flow mixing. The amount of flow mixing was reflected in the radial redistribution of total temperature as the flow passed through the stators. The data also show overturning of the tip flow at the stator exits that is consistent with the expected effect of the secondary flow field. The blockage factors calculated from the measured data show an increase in blockage across the rotors and a decrease across the stators.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AGARD Viscous Effects in Turbomachines; 23 p
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  • 17
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    Preliminary design of a supersonic cruise aircraft high-pressure turbine (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Development of the supersonic cruise aircraft engine continued in this National Aeronautics and Space Administration (NASA) sponsored Pratt and Whitney program for the Preliminary Design of an Advanced High-Pressure Turbine. Airfoil cooling concepts and the technology required to implement these concepts received particular emphasis. Previous supersonic cruise aircraft mission studies were reviewed and the Variable Stream Control Engine (VSCE) was chosen as the candidate or the preliminary turbine design. The design was evaluated for the supersonic cruise mission. The advanced technology to be generated from these designs showed benefits in the supersonic cruise application and subsonic cruise application. The preliminary design incorporates advanced single crystal materials, thermal barrier coatings, and oxidation resistant coatings for both the vane and blade. The 1990 technology vane and blade designs have cooled turbine efficiency of 92.3 percent, 8.05 percent Wae cooling and a 10,000 hour life. An alternate design with 1986 technology has 91.9 percent efficiency and 12.43 percent Wae cooling at the same life. To achieve these performance and life results, technology programs must be pursued to provide the 1990's technology assumed for this study.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-174878 , NAS 1.26:174878 , PWA-5923-14
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  • 18
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    Turbofan aft duct suppressor study program listing and user's guide (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A description of the structure of the Annular Flow Duct Program (AFDP) for the calculation of acoustic suppression due to treatment in a finite length annular duct carrying sheared flow is presented. Although most appropriate for engine exhaust ducts, this program can be used to study sound propagation in any duct that maintains annular geometry over a considerable length of the duct. The program is based on the modal analysis of sound propagation in ducts with axial segments of different wall impedances. For specified duct geometry, wall impedance, flow and acoustic conditions in the duct (including mode amplitude distribution of the source) and duct termination reflection characteristics, the program calculates the suppression due to the treatment in the duct. The presence of forward and backward traveling modes in the duct due to the reflection and redistribution of modes at segment interfaces and duct end terminations are taken into account in the calculations. The effects of thin wall boundary layers (with a linear or mean flow velocity profile) on the acoustic propagation are also included in the program. A functional description of the major subroutines is included and a sample run is provided with an explanation of the output.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-175067 , NAS 1.26:175067
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  • 19
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    All-purpose bidirectional four-quadrant controller (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The basic purpose of this paper is to provide some information regarding bidirectional four quadrant resonant power conversion and describe possible applications to aircraft electrical systems. As this technology has been developed sufficiently to demonstrate its feasibility, this is an appropriate time to evaluate the benefits of its application to aircraft electrical systems.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aircraft Elect. Secondary Power; p 189-196
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  • 20
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    Application of advanced materials to rotating machines (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: In discussing the application of advanced materials to rotating machinery, the following topics are covered: the torque speed characteristics of ac and dc machines, motor and transformer losses, the factors affecting core loss in motors, advanced magnetic materials and conductors, and design tradeoffs for samarium cobalt motors.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aircraft Elect. Secondary Power; p 93-101
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  • 21
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    Installation of electric generators on turbine engines (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The installation of generators on turbine aircraft is discussed. Emphasis is placed on the use of the samarium cobalt generator. Potential advantages of an electric secondary power system at the engine level are listed. The integrated generator and the externally mounted generator are discussed. It is concluded that the integrated generator is best used in turbojet and low bypass ratio engines where there is no easy way of placing generators externally without influencing frontal areas.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center Aircraft Elect. Secondary Power; p 73-78
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  • 22
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    Permanent-Magnet Motors and Generators for Aircraft (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Electric motors and generators that use permarotating machinery, but aspects of control and power conditioning are also considered. The discussion is structured around three basic areas: rotating machine design considerations presents various configuration and material options, generator applications provides insight into utilization areas and shows actual hardware and test results, and motor applications provides the same type of information for drive systems.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center Aircraft Elect. Secondary Power; p 79-91
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  • 23
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    Primary electric power generation systems for advanced-technology engines (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The advantages of the all electric airplane are discussed. In the all electric airplane the generator is the sole source of electric power; it powers the primary and secondary flight controls, the environmentals, and the landing gear. Five candidates for all electric power systems are discussed and compared. Cost benefits of the all electric airplane are discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center Aircraft Elect. Secondary Power; p 51-72
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  • 24
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    Computations of Emissions Using a 3-D Combustor Program (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A general 3-D combustor performance program developed by Garrett was extended to predict soot and NOx emissions. The soot formation and oxidation rates were computed by quasi-global models, taking into account the influence of turbulence. Radiation heat transfer was computed by the six-flux radiation mode. The radiation properties include the influence of CO2 and H2O in addition to soot. NOx emissions were computed from a global four-step hydrocarbon oxidation scheme and a set of rate-controlled reactions involving radicals and nitrogen oxides.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center Combust. Fundamentals Res.; p 171-182
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  • 25
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    Turbulent Combustor Flowfield Investigation (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The 2-D axisymmetric geometries under low speed, nonreacting, turbulent, swirling flow conditions were investigated. The effect of the parameters on isothermal flowfield patterns, time mean velocities and turbulence quantities is determined and an improved simulation in the form of a computer prediction code equipped with a suitable turbulence model is established. This is a prerequisite to the prediction of more complex turbulent reacting flows.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center Combust. Fundamentals Res.; p 101-118
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  • 26
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    Analytical calculation of a single jet in cross-flow and comparison with experiment (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A series of progressively finer grid systems to calculate the single jet in cross-flow experimentally measured were employed. The experimental measurements provide a collection of velocities, turbulence intensities, and jet concentration profiles with measurements of the inlet field. The use of a series of progressively finer grid systems allows a differentiation between numerical errors and the hydrodynamic modeling assumptions embodied in the 3D combustor code.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Combust. Fundamentals Res.; p 93-100
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  • 27
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    Dilution Jet Experiments in Compact Combustor Configurations (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The effects of cooling jets on the velocity and temperature fields in a compact reverse flow combustion are discussed. The work is motivated by the need to limit the temperature of past-combustion gases in jet engines to values within the endurance capabilities of turbine blades. The application requires not only that the temperature be kept sufficiently low but also that a suitably tailored temperature profile be provided at the combustor exit, with higher temperatures generally permissible at the blade tip than at the blade root because of higher centrifugal loads at the root. A single jet. As spacing is reduced, jet penetration is also reduced, and the cooling jets tend to remain close to the wall from which they are injected. Results suggest that cooling and temperature distribution tailoring can be accomplished without injecting cooling jets upstream of the turn, and thus it appears that combustors can be made smaller than current designs.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center Combust. Fundamentals Res.; p 85-92
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  • 28
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    Pollutant Formation in Monodisperse Fuel Spray Combustion (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The combustion of liquid sprays represents an extremely important class of combustion processes. In the transition region, encompassing droplet sizes in the range of 25-80 micron diameter, the mixing and evaporation processes are both incomplete at the flame front and burning occurs in a combined diffusive and premixed fashion. Under these conditions, the relative importance of heterogeneous and homogeneous effects in dominating the combustion process is switched and gives rise to a number of interesting phenomena. NO (sub x) formation in monodisperse spray combustion was investigated with the following specific objectives: (1) to quantitatively determine the effect of droplet size, number density, etc. on NO sub x formation in monodisperse fuel spray combustion; and (2) to isolate the important physical and chemical phenomena in NO sub x formation in these combustion systems.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center Combust. Fundamentals Res.; p 39-47
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  • 29
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    Fuel Spray Diagnostics (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Fundamental experimental data base for turbulent flow mixing models is provided and better prediction of the more complex turbulent chemical reacting flows. Analytical application to combustor design is provided and a better fundamental understanding of the combustion process.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Combust. Fundamentals Res.; p 29-38
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  • 30
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    Numerical Simulation for Droplet Combustion Using Lagrangian Hydrodynamics (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A predictive model of spray combustion must incorporate models for the wide variety of physical environments in a practical combustor. In regions where droplets are closely spaced, combustion resembles a diffusion flame; where they are well separated, an envelope or wake flame results. The relative velocity field between the fuel droplets and oxidizer in influences boundary layer development about the droplet, recirculating flow patterns, and droplet shape and stability. A model must encompass these interacting temporal and spatial effects as well as complicated combustor boundaries. The objective of the current work is to develop the triangular gridding method for describing the individual and collective properties of vaporizing and burning fuel droplets.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center Combust. Fundamentals Res.; p 7-12
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  • 31
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    Analytical Modeling of Operating Characteristics of Premixing-prevaporizing Fuel-air Mixing Passages (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A model for predicting the distribution of liquid fuel droplets and fuel vapor in premixing-prevaporizing fuel-air mixing passages of the direct injection type is described. This model consists of three computer programs: a calculation of the two dimensional or axisymmetric air flow field neglecting the effects of fuel; a calculation of the three dimensional fuel droplet trajectories and evaporation rates in a known, moving air flow; and a calculation of fuel vapor diffusing into a moving three dimensional air flow with source terms dependent on the droplet evaporation rates. The air flow calculation can treat compressible swirling flows in arbitrary ducts with arbitrary distributions of temperature and velocity as initial conditions. The fuel droplets are treated as initial conditions. The fuel droplets are treated as individual particle classes each satisfying Newton's law, a heat transfer, and a mass transfer equation. The vapor diffusion calculation treats three dimensional, gas phase, turbulent diffusion processes with the turbulence level determined by the air flow calculations and the source terms determined by the droplet evaporation rates.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center Combust. Fundamentals Res.; p 1-6
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  • 32
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    Advanced rotary engines (1983)
    In:  Other Sources
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    Publication Date: 2016-06-07
    Description: The broad objectives of this paper are the following: (1) to summarize the Curtiss-Wright design, development and field testing background in the area of rotary aircraft engines; (2) to briefly summarize past activity and update development work in the area of stratified charge rotary combustion engines; and (3) to discuss the development of a high-performance direct injected unthrottled stratified charge rotary combustion aircraft engine. Efficiency improvements through turbocharging are also discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center Aviation Gasolines and Future Alternatives; p 123-137
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  • 33
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    General Aviation Turbine Engine (GATE) Overview (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: When all the technology studies were done and the accompanying market analyses were complete, the conclusion was that it is indeed possible to reduce the cost of turbine engines by a factor of 3 using low-cost manufacturing techniques and increased production rates. In the interest of reducing engine cost, some performance was sacrificed. Yet we ended up with about a 20 percent predicted improvement in SFC over current technology turboprops. However, even this level of improvement does not match the low SFC of reciprocating powerplants--particularly those advanced concepts described earlier. The 20 percent better SFC and much lower weight of a turboprop does mean that if such a powerplant were installed in a resized small airplane, one could save between 10 and 30 percent fuel relative to existing recip engines, depending on different mission and airplane combinations. The price of the aircraft would go down about 15 percent in the case of a high powered single, or 25 percent in the case of a normal size twin. The operating costs would decrease about 10 percent in the case of the single, and as much as 35 percent in the case of the twin.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aviation Gasolines and Future Alternatives; p 161-166
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    An overview of general aviation propulsion research programs at NASA Lewis Research Center (1983)
    In:  Other Sources
    Details
    Publication Date: 2016-06-07
    Description: The review covers near-term improvements for current-type piston engines, as well as studies and limited corroborative research on several advanced g/a engine concepts, including diesels, small turboprops and both piston and rotary stratified-charge engines. Also described is basic combustion research, cycle modeling and diagnostic instrumentation work that is required to make new engines a reality.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aviation Gasolines and Future Alternatives; p 149-160
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  • 35
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    Lightweight diesel aircraft engines for general aviation (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Two different engines were studied. The advantages of a diesel to general aviation were reduced to fuel consumption, reduced operating costs, and reduced fire and explosion hazard. There were no ignition mixture control or inlet icing problems. There are fewer controls and no electrical interference problems.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center Aviation Gasolines and Future Alternatives; p 136-147
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  • 36
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    Energy efficient engine, high pressure turbine thermal barrier coating. Support technology report (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This report describes the work performed on a thermal barrier coating support technology task of the Energy Efficient Engine Component Development Program. A thermal barrier coating (TBC) system consisting of a Ni-Cr-Al-Y bond cost layer and ZrO2-Y2O3 ceramic layer was selected from eight candidate coating systems on the basis of laboratory tests. The selection was based on coating microstructure, crystallographic phase composition, tensile bond and bend test results, erosion and impact test results, furnace exposure, thermal cycle, and high velocity dynamic oxidation test results. Procedures were developed for applying the selected TBC to CF6-50, high pressure turbine blades and vanes. Coated HPT components were tested in three kinds of tests. Stage 1 blades were tested in a cascade cyclic test rig, Stage 2 blades were component high cycle fatigue tested to qualify thermal barrier coated blades for engine testing, and Stage 2 blades and Stage 1 and 2 vanes were run in factory engine tests. After completion of the 1000 cycle engine test, the TBC on the blades was in excellent condition over all of the platform and airfoil except at the leading edge above midspan on the suction side of the airfoil. The coating damage appeared to be caused by particle impingement; adjacent blades without TBC also showed evidence of particle impingement.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-168037 , NAS 1.26:168037 , R82AEB293
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  • 37
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    High pressure compressor component performance report (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A compressor optimization study defined a 10 stage configuration with a 22.6:1 pressure ratio, an adiabatic efficiency goal of 86.1%, and a polytropic efficiency of 90.6%; the corrected airflow is 53.5 kg/s. Subsequent component testing included three full scale tests: a six stage rig test, a 10 stage rig test, and another 10 stage rig test completed in the second quarter of 1982. Information from these tests is used to select the configuration for a core engine test and an integrated core/low spool test. The test results will also provide data base for the flight propulsion system. The results of the test series with both aerodynamic and mechanical performance of each compressor build are presented. The second 10 stage compressor adiabatic efficiency was 0.848 at a cruise operating point versus a test goal of 0.846.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-168245 , NAS 1.26:168245 , R82AEB437
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  • 38
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    Creep fatigue life prediction for engine hot section materials (isotropic) (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The Hot Section Technology (HOST) program, creep fatigue life prediction for engine hot section materials (isotropic), is reviewed. The program is aimed at improving the high temperature crack initiation life prediction technology for gas turbine hot section components. Significant results include: (1) cast B1900 and wrought IN 718 selected as the base and alternative materials respectively; (2) fatigue test specimens indicated that measurable surface cracks appear early in the specimen lives, i.e., 15% of total life at 871 C and 50% of life at 538 c; (3) observed crack initiation sites are all surface initiated and are associated with either grain boundary carbides or local porosity, transgrannular cracking is observed at the initiation site for all conditions tested; and (4) an initial evaluation of two life prediction models, representative of macroscopic (Coffin-Mason) and more microscopic (damage rate) approaches, was conducted using limited data generated at 871 C and 538 C. It is found that the microscopic approach provides a more accurate regression of the data used to determine crack initiation model constants, but overpredicts the effect of strain rate on crack initiation life for the conditions tested.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-168228 , NAS 1.26:168228 , PWA-5894-17 , AR-1
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  • 39
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    Circulation control propellers for general aviation, including a BASIC computer program (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The feasibility of replacing variable pitch propeller mechanisms with circulation control (Coanada effect) propellers on general aviation airplanes was examined. The study used a specially developed computer program written in BASIC which could compare the aerodynamic performance of circulation control propellers with conventional propellers. The comparison of aerodynamic performance for circulation control, fixed pitch and variable pitch propellers is based upon the requirements for a 1600 kg (3600 lb) single engine general aviation aircraft. A circulation control propeller using a supercritical airfoil was shown feasible over a representative range of design conditions. At a design condition for high speed cruise, all three types of propellers showed approximately the same performance. At low speed, the performance of the circulation control propeller exceeded the performance for a fixed pitch propeller, but did not match the performance available from a variable pitch propeller. It appears feasible to consider circulation control propellers for single engine aircraft or multiengine aircraft which have their propellers on a common axis (tractor pusher). The economics of the replacement requires a study for each specific airplane application.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-165968 , NAS 1.26:165968
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  • 40
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    Energy efficient engine high-pressure turbine component rig performance test report (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A rig test of the cooled high-pressure turbine component for the Energy Efficient Engine was successfully completed. The principal objective of this test was to substantiate the turbine design point performance as well as determine off-design performance with the interaction of the secondary flow system. The measured efficiency of the cooled turbine component was 88.5 percent, which surpassed the rig design goal of 86.5 percent. The secondary flow system in the turbine performed according to the design intent. Characterization studies showed that secondary flow system performance is insensitive to flow and pressure variations. Overall, this test has demonstrated that a highly-loaded, transonic, single-stage turbine can achieve a high level of operating efficiency.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-168189 , NAS 1.26:168189 , PWA-5594-243
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  • 41
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    Multi-fuel rotary engine for general aviation aircraft (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Design studies of advanced multifuel general aviation and commuter aircraft rotary stratified charge engines are summarized. Conceptual design studies were performed at two levels of technology, an advanced general aviation engines sized to provide 186/250 shaft kW/hp under cruise conditions at 7620 (25,000 m/ft) altitude. A follow on study extended the results to larger (2500 hp max.) engine sizes suitable for applications such as commuter transports and helicopters. The study engine designs were derived from relevant engine development background including both prior and recent engine test results using direct injected unthrottled rotary engine technology. Aircraft studies, using these resultant growth engines, define anticipated system effects of the performance and power density improvements for both single engine and twin engine airplanes. The calculated results indicate superior system performance and 27 to 33 percent fuel economy improvement for the rotary engine airplanes as compared to equivalent airframe concept designs with current baseline engines. The research and technology activities required to attain the projected engine performance levels are also discussed. Previously announced in STAR as N83-18910
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 83-1340
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  • 42
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    Tip cap for a rotor blade (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A replaceable tip cap for attachment to the end of a rotor blade is described. The tip cap includes a plurality of walls defining a compartment which, if desired, can be divided into a plurality of subcompartments. The tip cap can include inlet and outlet holes in walls thereof to permit fluid communication of a cooling fluid there through. Abrasive material can be attached with the radially outer wall of the tip cap.
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 43
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    Annulus wall boundary layer development in a compressor stage, including the effects of tip clearance (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The end-wall boundary layer development in a compressor stage, including the inlet guide vane (IGV) passage and the rotor passage, was measured. The measurement upstream of the rotor and inside the IGV passage were carried out with a five-hole probe. The data (blade-to-blade) inside the IGV passage were carried out with a five-hole probe. The data (blade-to-blade) inside the rotor passage were measured using a three-sensor rotating hot-wire below the tip clearance region and "V' configuration probe inside the clearance region. The rotor exit measurements (blade-to-blade) were acquired with a laser Doppler velocimeter. The velocity profiles and the integral properties are presented and interpreted. The boundary layer is comparatively well behaved up to the leading edge of the rotor, beyond which complex interactions result in very unconventional profiles. The momentum thicknesses decrease in the leakage flow region of the rotor. The momentum thicknesses and the limiting streamline angles predicted from a momentum integral technique agree well with the data up to the leading edge of the rotor.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AGARD Viscous Effects in Turbomachines; 17 p
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  • 44
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    Determination of the static performance of a Cuyuna cc model UL-430RR engine (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The results of static performance tests were carried out on an ultralight engine. A Cuyuna 430 cc, 2 stroke, 2 cylinder model was used to measure thrust, torque, propeller RPM, fuel flow, cylinder head temperature, and change in pressure through the propeller. Measurement of each of the above parameters was taken at specific values of RPM. The propeller's RPM's ranged from idle at approximately 750 RPM to a maximum value of 2810 RPM. The test results were then manipulated to obtain thrust coefficient, power coefficient, shaft horse power, and shaft specific fuel consumption.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-175354 , NAS 1.26:175354 , KU-FRL-6135-1
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  • 45
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    Aerothermal modeling, phase 1. Volume 2: Experimental data (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The experimental test effort is discussed. The test data are presented. The compilation is divided into sets representing each of the 18 experimental configurations tested. A detailed description of each configuration, and plots of the temperature difference ratio parameter or pattern factor parameter calculated from the test data are also provided.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-168296-VOL-2 , NAS 1.26:168296-VOL-2
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  • 46
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    Aerothermal modeling, phase 1. Volume 1: Model assessment (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Phase 1 was conducted as part of the overall NASA Hot Section Technology (HOST) Program. The purpose of this effort was to determine the predictive accuracy of and the deficiencies within the various analytical modules comprising the overall combustor aerothermal model used at General Electric, as well as to formulate recommendations for improvement where needed. This effort involved the assembly of a benchmark quality data base from selected available literature, and from General Electric engine and combustor component test data. This data base was supplemented with additional definitive data obtained from an experimental test program conducted as part of the Phase 1 effort. Using selections from this data base, assessment studies were conducted to evaluate the various modules. Assessment of the internal flow module was conducted using 2-D parabolic and ellipitic, as well as 3-D elliptic internal flow calculations of definitive test data selected from the assembled data base. The 2-D assessment provided methodical examination of the mathematical techniques and the physical submodules, while the 3-D assessment focused on usefulness as a design tool. Calculations of combustor linear metal temperatures, pressure loss performance, and airflow distribution were performed using aerothermal modules which were in general use for many years at General Electric. The results of these assessment provided for the identification of deficiencies within the modules. The deficiencies were addressed in some detail providing a foundation on which to formulate a prioritized list of recommendations for improvement.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-168296-VOL-1 , NAS 1.26:168296-VOL-1
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  • 47
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    A comprehensive method for preliminary design optimization of axial gas turbine stages. II - Code verification (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The present effort represents an extension of previous work wherein a calculation model for performing rapid pitchline optimization of axial gas turbine geometry, including blade profiles, is developed. The model requires no specification of geometric constraints. Output includes aerodynamic performance (adiabatic efficiency), hub-tip flow-path geometry, blade chords, and estimates of blade shape. Presented herein is a verification of the aerodynamic performance portion of the model, whereby detailed turbine test-rig data, including rig geometry, is input to the model to determine whether tested performance can be predicted. An array of seven (7) NASA single-stage axial gas turbine configurations is investigated, ranging in size from 0.6 kg/s to 63.8 kg/s mass flow and in specific work output from 153 J/g to 558 J/g at design (hot) conditions; stage loading factor ranges from 1.15 to 4.66.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 83-1403
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    The performance of an annular vane swirler (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: In connection with the desirability of optimizing the design of a gas turbine combustion chamber, there exists a need for a more complete understanding of the fluid dynamics of the flow in such chambers. In order to satisfy this need, experimental and theoretical research is being conducted with the objective to study two-dimensional axisymmetric geometries under low speed, nonreacting, turbulent, swirling flow conditions. The flow enters the test section and proceeds into a larger chamber. Inlet swirl vanes are adjustable to a variety of vane angles. The present investigation concentrates on the time-mean flow characteristics which are generated by the upstream annular swirler. The investigation makes use of a five-hole pitot probe technique. A theoretical analysis of swirl numbers associated with several idealized exit velocity profiles is included, and values of the ratio of maximum swirl velocity to maximum axial velocity at different swirl strengths are given for each case.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 83-1326
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  • 49
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    Ejector nozzle test results at simulated flight conditions for an advanced supersonic transport propulsion system (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Results are presented of wind tunnel tests conducted to verify the performance improvements of a refined ejector nozzle design for advanced supersonic transport propulsion systems. The analysis of results obtained at simulated engine operating conditions is emphasized. Tests were conducted with models of approximately 1/10th scale which were configured to simulate nozzle operation at takeoff, subsonic cruise, transonic cruise, and supersonic cruise. Transonic cruise operation was not a consideration during the nozzle design phase, although an evaluation at this condition was later conducted. Test results, characterized by thrust and flow coefficients, are given for a range of nozzle pressure ratios, emphasizing the thrust performance at the engine operating conditions predicted for each flight Mach number. The results indicate that nozzle performance goals were met or closely approximated at takeoff and supersonic cruise, while subsonic cruise performance was within 2.3 percent of the goal with further improvement possible.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 83-1287
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  • 50
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    Application of 3D aerodynamic/combustion model to combustor primary zone study (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A description is provided of the three-dimensional elliptic code for reacting flows used in the combustor design process during the program 'Small Gas Turbine Combustor Primary Zone Study' carried out by a U.S. company. The code, designated MARC-I (multidimensional aerodynamic recirculating combustion-Version I) is an adaptation of the model described by Mongia et al. (1979). The program has the objective to advance the technology of the small reverse-flow annular combustor design through an understanding of primary zone performance factors. The MARC-I code was used for performance predictions of both original designs and later modifications. A test program consisting of both primary zone sampling and overall combustor performance measurements was carried out. It was, therefore, possible to compare the analytical predictions with actual test measurements.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 83-1265
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    Importance of inlet boundary conditions for numerical simulation of combustor flows (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Fluid dynamic computer codes for the mathematical simulation of problems in gas turbine engine combustion systems are required as design and diagnostic tools. To eventually achieve a performance standard with these codes of more than qualitative accuracy it is desirable to use benchmark experiments for validation studies. Typical of the fluid dynamic computer codes being developed for combustor simulations is the TEACH (Teaching Elliptic Axisymmetric Characteristics Heuristically) solution procedure. It is difficult to find suitable experiments which satisfy the present definition of benchmark quality. For the majority of the available experiments there is a lack of information concerning the boundary conditions. A standard TEACH-type numerical technique is applied to a number of test-case experiments. It is found that numerical simulations of gas turbine combustor-relevant flows can be sensitive to the plane at which the calculations start and the spatial distributions of inlet quantities for swirling flows.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 83-1263
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  • 52
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    In-flight acoustic test results for the SR-2 and SR-3 advanced-design propellers (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Several advanced-design propellers, previously tested in the wind tunnel at the Lewis Research Center, have been tested in flight at the Dryden Flight Research Facility. The flight-test propellers were mounted on a pylon on the top of the fuselage of a JetStar airplane. Acoustic data for the advanced-design SR-2 and SR-3 propellers at Mach numbers to 0.8 and helical-tip Mach numbers to 1.15 are presented; maximum blade-passage frequency sound-pressure levels are also compared.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 83-1214
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  • 53
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    Effects of interstage diffuser flow distortion on the performance of a 15.41-centimeter tip diameter axial power turbine (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The performance of a variable-area stator, axial flow power turbine was determined in a cold-air component research rig for two inlet duct configurations. The two ducts were an interstage diffuser duct and an accelerated-flow inlet duct which produced stator inlet boundary layer flow blockages of 11 percent and 3 percent, respectively. Turbine blade total efficiency at design point was measured to be 5.3 percent greater with the accelerated-flow inlet duct installed due to the reduction in inlet blockage. Blade component measurements show that of this performance improvement, 35 percent occurred in the stator and 65 percent occurred in the rotor. Analysis of inlet duct internal flow using an Axisymmetric Diffuser Duct Code (ADD Code) were in substantial agreement with the test data.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 83-1179
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    The aerodynamic design and performance of the General Electric/NASA EEE fan (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The aerodynamic design and test results of the fan and quarter-stage component for the GE/NASA Energy Efficient Engine (EEE) are presented. The fan is a high bypass ratio, single-stage design having 32 part-span shrouded rotor blades, coupled with a unique quarter-stage arrangement that provides additional core-stream pressure ratio and particle separation. The fan produces a bypass pressure ratio of 1.65 at the exit of the low aspect ratio vane/frame and a core-stream pressure ratio of 1.67 at the entrance to the core frame struts. The full-scale fan vehicle was instrumented, assembled and tested as a component in November 1981. Performance mapping was conducted over a range of speeds and bypass ratios using individually-controlled bypass and core-stream discharge valves. The fan bypass and core-stream test data showed excellent results, with the fan exceeding all performance goals at the important engine operating conditions.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 83-1160
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  • 55
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    Advanced propfan engine characteristics and technology needs (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: A comparative study is presented for two of the advanced gas turbine engine designs developed in the course of a proprietary research effort for the NASA Advanced Propfan Engine Technology research program. In these engines, a cycle pressure ratio of 32.5:1 and a 2500 F maximum turbine temperature provide fuel efficient operation in the 32,000-ft altitude, Mach 0.72 cruise speed regime stipulated. Both of the engine configurations incorporate three spools, of which the compressors are dual-spool and the power turbines are free. A major design challenge for axial compressors in the 10,000-shp class was the maintenance of adequate blade heights in the later stages.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 83-1155
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  • 56
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    Effects of friction dampers on aerodynamically unstable rotor stages (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Attention is given to the physical concepts and mathematical techniques useful in the analysis of the stabilizing effect of friction on aerodynamically unstable rotor stages. Results are presented for three-, four-, and five-bladed disks. In the present multidegree-of-freedom model of an aerodynamically unstable rotor stage, a harmonic steady state solution due to the friction dampers may be either a stability limit, a stable cycle limit, or neither. A criterion is established in the form of an energy function which determines whether the solution is a stability limit. In the event that the initial displacement and velocity exeed those associated with the steady state solution corresponding to a stability limit, the reponse becomes unbounded.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 83-0848
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  • 57
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    Structural dynamics studies of rotating bladed-disk assemblies coupled with flexible shaft motions (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: In order to analyze the dynamic behavior of the first stage compressor/fan of the 'E3' turbofan engine, a classical structural dynamics approach is employed to couple the motions of a flexible bladed disk to a rotating flexible shaft. The analysis accounts for flexible disk displacements which are transverse to the plane of rotation, and radial as well as tangential, and also accounts for rigid disk translations along, and rotations about, axes normal to the undeformed shaft axes. In the case of a wide range of E3 engine shaft flexibilities and speeds, some of the one-diametral node frequencies are shown to be affected by shaft degrees of freedom whose stiffness values are in general range of design practice. Coriolis forces are also found to significantly affect natural frequencies where strong coupling between certain modes is present.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 83-0919
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  • 58
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    Flight evaluation of the DEEC secondary control air-start capability (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The air-start capability of a secondary engine control (SEC) was tested for a DEEC-equipped F100 engine and installed in an F-15 airplane. Two air-start schedules were tested. The first was referred to as the group I schedule; the second or revised schedule was the group II start schedule. Using the group I start schedule, an airspeed of 300 knots was required to ensure successful 40- and 25-percent SEC-mode air starts. If N2 were less than 40 percent, a stall would occur when the start bleeds closed 40 sec after initiation of the air start. All JFS-assisted air starts were successful with the group start schedule. For the group II schedule, the time between pressurization and start-bleed closure ranged between 50 and 72 sec depending on altitude. All air starts were successful above 225 knots givin a 75-knot reduction in required airspeed for a successful air start. Spooldown air starts of 40 percent were successful at 200 knots at altitudes up to 10,650 m and at 175 knots at altitudes up to 6100 m. Idle rpm was lower than the desired 65 percent for air starts at higher altitudes and lower airspeeds. All JSF-assisted air starts were successful.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-84910 , H-1186 , NAS 1.15:84910
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    Digital computer program for generating dynamic turbofan engine models (DIGTEM) (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This report describes DIGTEM, a digital computer program that simulates two spool, two-stream turbofan engines. The turbofan engine model in DIGTEM contains steady-state performance maps for all of the components and has control volumes where continuity and energy balances are maintained. Rotor dynamics and duct momentum dynamics are also included. Altogether there are 16 state variables and state equations. DIGTEM features a backward-differnce integration scheme for integrating stiff systems. It trims the model equations to match a prescribed design point by calculating correction coefficients that balance out the dynamic equations. It uses the same coefficients at off-design points and iterates to a balanced engine condition. Transients can also be run. They are generated by defining controls as a function of time (open-loop control) in a user-written subroutine (TMRSP). DIGTEM has run on the IBM 370/3033 computer using implicit integration with time steps ranging from 1.0 msec to 1.0 sec. DIGTEM is generalized in the aerothermodynamic treatment of components.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-83446 , E-1748 , NAS 1.15:83446
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    Optimal mistuning for enhanced aeroelastic stability of transonic fans (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An inverse design procedure was developed for the design of a mistuned rotor. The design requirements are that the stability margin of the eigenvalues of the aeroelastic system be greater than or equal to some minimum stability margin, and that the mass added to each blade be positive. The objective was to achieve these requirements with a minimal amount of mistuning. Hence, the problem was posed as a constrained optimization problem. The constrained minimization problem was solved by the technique of mathematical programming via augmented Lagrangians. The unconstrained minimization phase of this technique was solved by the variable metric method. The bladed disk was modelled as being composed of a rigid disk mounted on a rigid shaft. Each of the blades were modelled with a single tosional degree of freedom.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-173179 , NAS 1.26:173179 , GTL-176
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    Comparison of Results Obtained from Flight Tests and Simulated Tests of a Digital Electronic Engine Control System in an F-15 Airplane (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Substantial benefits of a full authority digital electronic engine control on an air breathing engine were demonstrated repeatedly in simulation studies, ground engine tests, and engine altitude test facilities. A digital engine electronic control system showed improvements in efficiency, performance, and operation. An additional benefit of full authority digital controls is the capability of detecting and correcting failures and providing engine health diagnostics.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-84903 , NAS 1.15:84903
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    Experimental study of the operating characteristics of premixing-prevaporizing fuel/air mixing passages (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Fuel spray and air flow characteristics were determined using nonintrusive (optical) measurement techniques in a fuel preparation duct. A very detailed data set was obtained at high pressures (to 10 atm) and temperatures (to 750 K). The data will be used to calibrate an analytical model which will facilitate the design of a lean premixed prevaporized combustor. This combustor has potential for achieving low pollutant emissions and low levels of flame radiation and pattern factors conductive to improved durability and performance for a variety of fuels.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-168279 , NAS 1.26:168279 , SR83-R-4663-30
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    Preliminary scramjet design for hypersonic airbreathing missile application (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A conceptual design study of a scramjet engine was conducted for a hypersonic surface to air missile (HYSAM). The definition of the engine was based upon the requirements of accelerating the HYSAM from Mach 4 at 20,000 feet to Mach 6 at 100,000 feet and the cruise conditions at Mach 6. The resulting external and internal environmental conditions were used by various engineering disciplines performing design, stress and heat transfer analysis. A detailed structural analysis was conducted along with an indepth thermal analysis. Structurally all the components within the system exhibit positive margins of safety. A feasible concept was defined which uses state-of-the-art materials and existing TMC technology. The engine basically consists of a three dimensional carbon/carbon combustor/nozzle secured to an FS-85 columbium inlet. The carbon/carbon liner is sheathed with carbon felt insulation to thermally protect the FS-85 structure and skin. The thermal analysis of the engine indicates that a thermally viable configuration exists.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-3742 , NAS 1.26:3742 , S-1585
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    A Preliminary Study of Solar Powered Aircraft and Associated Power Trains (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The feasibility of regeneratively powered solar high altitude powered platform (HAPP) remotely piloted vehicles was assessed. Those technologies which must be pursued to make long duration solar HAPPs feasible are recommended. A methodology which involved characterization and parametric analysis of roughly two dozen variables to determine vehicles capable of fulfilling the primary mission are defined. One of these vehicles was then conceptually designed. Variations of each major design parameter were investigated along with state-of-the-art changes in power train component capabilities. The midlatitude mission studied would be attainable by a solar HAPP if fuel cell, electrolyzer and photovoltaic technologies are pursued. Vehicles will be very large and have very lightweight structures in order to attain the combinations of altitude and duration required by the primary mission.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-3699 , NAS 1.26:3699
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    Blade loss transient dynamics analysis with flexible bladed disk (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The transient dynamic response of a flexible bladed disk on a flexible rotor in a two rotor system is formulated by modal synthesis and a Lagrangian approach. Only the nonequilibrated one diameter flexible mode is considered for the flexible bladed disk, while the two flexible rotors are represented by their normal modes. The flexible bladed disk motion is modeled as a combination of two one diameter standing waves, and is coupled inertially and gyroscopically to the flexible rotors. Application to a two rotor model shows that a flexible bladed disk on one rotor can be driven into resonance by an unbalance in the other rotor, and at a frequency equal to the difference in the rotor speeds.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-168176 , NAS 1.26:168176
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    Numerical modeling of turbulent flow in a channel (1983)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: Two-dimensional incompressible turbulent flow in a channel with a backward-facing step was studied numerically by Chorin's Random Vortex Method (RVM), an algorithm capable of tracing the action of elementary turbulent eddies and their cumulative effects without imposing any restrictions upon their motions. The step occurs in one side of a channel with otherwise flat, parallel walls; its height equals 1/3, 1/4 or 1/5 the width of the channel downstream. The main objective was to investigate the behavior of the large-scale turbulent eddies in a flow and the flow characteristics in the separated shear layer, the reattached zone, and the rebuilding boundary layer after reattachment. The unsteady vorticity field and the distribution of time-averaged turbulent statistics were obtained. The effects of expansion step height and initial boundary layer state were also studied. Comparisons were made with the available experimental results. The agreement is satisfactory in the velocity profiles and in the reattachment length, and fairly good in the turbulence profiles. Also a mechanism of the development of the reattaching turbulent flow was suggested by the numerical results.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-168278 , DOE/NASA/0131-2 , NAS 1.26:168278
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    A theoretical and experimental study of turbulent particle-laden jets (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Mean and fluctuating velocities of both phases, particle mass fluxes, particle size distributions in turbulent particle-laden jets were measured. The following models are considered: (1) a locally homogeneous flow (LHF) model, where slip between the phases was neglected; (2) a deterministic separated flow (DSF) model, where slip was considered but effects of particle dispersion by turbulence were ignored; and (3) a stochastic separated flow (SSF) model. The SSF model performed reasonably well with no modifications in the prescriptions for eddy properties from its original calibration. A modified k- model, incorporating direct contributions of interphase transport on turbulence properties (turbulence modulation), was developed within the framework of the SSF model.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-168293 , NAS 1.26:168293
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    F100 Multivariable Control Synthesis Program. Computer Implementation of the F100 Multivariable Control Algorithm (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: As turbofan engines become more complex, the development of controls necessitate the use of multivariable control techniques. A control developed for the F100-PW-100(3) turbofan engine by using linear quadratic regulator theory and other modern multivariable control synthesis techniques is described. The assembly language implementation of this control on an SEL 810B minicomputer is described. This implementation was then evaluated by using a real-time hybrid simulation of the engine. The control software was modified to run with a real engine. These modifications, in the form of sensor and actuator failure checks and control executive sequencing, are discussed. Finally recommendations for control software implementations are presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TP-2231 , E-1496 , NAS 1.60:2231
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    Study of controlled diffusion stator blading (1983)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: Tests were conducted on a high tip speed, highly loaded front compressor stage having low aspect ratio rotor and stator airfoils. The stator airfoils were designed by the controlled diffusion procedure recently developed by P&WA for designing transonic cascade airfoils. The rotor blades consisted of multiple-circular-arc airfoil sections. The stage had a tip speed of 442 m/sec (1450 ft/sec), a hub/tip ratio of 0.597, a rotor aspect ratio of 1.3, and a stator aspect ratio of 1.45. At design speed the rotor-stator stage achieved an adiabatic efficiency of 89.1% at design flow and pressure ratio. Surge margin was 14%. The stage efficiency exceeded the design goal by 0.6 percentage points. The rotor efficiency was 92.4%, exceeding design by 0.3 percentage points. The controlled diffusion stator demonstrated a lower minimum loss over the multiple-circular-arc stator from the root to 70 percent span. A surge diffusion factor of 0.72 was reached at both the rotor tip and the stator root. The NAS3-22008 program demonstrated its intent: high efficiency and loading levels with low aspect ratio blades and the controlled diffusion stator in the unfavorable front stage environment.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-167995 , NAS 1.26:167995 , PWA-5698-77
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    Energy Efficient Engine Flight Propulsion System Preliminary Analysis and Design Report (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The final design and analysis of the flight propulsion system is presented. This system is the conceptual study engine defined to meet the performance, economic and environmental goals established for the Energy Efficient Engine Program. The design effort included a final definition of the engine, major components, internal subsystems, and nacelle. Various analytical representations and results from component technology programs are used to verify aerodynamic and structural design concepts and to predict performance. Specific design goals and specifications, reflecting future commercial aircraft propulsion system requirements for the mid-1980's, are detailed by NASA and used as guidelines during engine definition. Information is also included which details salient results from a separate study to define a turbofan propulsion system, known as the maximum efficiency engine, which reoptimized the advanced fuel saving technologies for improved fuel economy and direct operating costs relative to the flight propulsion system.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-174701 , NAS 1.26:174701 , PWA-5594-248
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    Turbofan aft duct suppressor study (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Suppressions due to acoustic treatment in the annular exhaust duct of a model fan were theoretically predicted and compared with measured suppressions. The predictions are based on the modal analysis of sound propagation in a straight annular flow duct with segmented treatment. Modal distributions of the fan noise source (fan-stator interaction only) were measured using in-duct modal probes. The flow profiles were also measured in the vicinity of the modal probes. The acoustic impedance of the single degree of freedom treatment was measured in the presence of grazing flow. The measured values of mode distribution of the fan noise source, the flow velocity profile and the acoustic impedance of the treatment in the duct were used as input to the prediction program. The predicted suppressions, under the assumption of uniform flow in the duct, compared well with the suppressions measured in the duct for all test conditions. The interaction modes generated by the rotor-stator interaction spanned a cut-off ratio range from nearly 1 to 7.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-175067 , NAS 1.26:175067 , R83AEB566
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    Turbofan aft duct suppressor study. Contractor's data report of mode probe signal data (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Acoustic modal distributions were measured in a fan test model having an annular exhaust duct for comparison with theoretically predicted acoustic suppression values. This report contains the amplitude and phase data of the acoustic signals sensed by the transducers of the two mode probes employed in the measurement. Each mode probe consisted of an array of 12 transducers sensing the acoustic field at three axial positions and four radial positions.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-175067 , NAS 1.26:175067
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    Flutter and forced response of mistuned rotors using standing wave analysis (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A standing wave approach is applied to the analysis of the flutter and forced response of tuned and mistuned rotors. The traditional traveling wave cascade airforces are recast into standing wave arbitrary motion form using Pade approximants, and the resulting equations of motion are written in the matrix form. Applications for vibration modes, flutter, and forced response are discussed. It is noted that the standing wave methods may prove to be more versatile for dealing with certain applications, such as coupling flutter with forced response and dynamic shaft problems, transient impulses on the rotor, low-order engine excitation, bearing motion, and mistuning effects in rotors.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-173555 , NAS 1.26:173555 , GT/PDL-170
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    Aerothermal modeling. Executive summary (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: One of the significant ways in which the performance level of aircraft turbine engines has been improved is by the use of advanced materials and cooling concepts that allow a significant increase in turbine inlet temperature level, with attendant thermodynamic cycle benefits. Further cycle improvements have been achieved with higher pressure ratio compressors. The higher turbine inlet temperatures and compressor pressure ratios with corresponding higher temperature cooling air has created a very hostile environment for the hot section components. To provide the technology needed to reduce the hot section maintenance costs, NASA has initiated the Hot Section Technology (HOST) program. One key element of this overall program is the Aerothermal Modeling Program. The overall objective of his program is to evolve and validate improved analysis methods for use in the design of aircraft turbine engine combustors. The use of such combustor analysis capabilities can be expected to provide significant improvement in the life and durability characteristics of both combustor and turbine components.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-168330 , NAS 1.26:168330
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    Experimental and theoretical study of combustion jet ignition (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A combustion jet ignition system was developed to generate turbulent jets of combustion products containing free radicals and to discharge them as ignition sources into a combustible medium. In order to understand the ignition and the inflammation processes caused by combustion jets, the studies of the fluid mechanical properties of turbulent jets with and without combustion were conducted theoretically and experimentally. Experiments using a specially designed igniter, with a prechamber to build up and control the stagnation pressure upstream of the orifice, were conducted to investigate the formation processes of turbulent jets of combustion products. The penetration speed of combustion jets has been found to be constant initially and then decreases monotonically as turbulent jets of combustion products travel closer to the wall. This initial penetration speed to combustion jets is proportional to the initial stagnation pressure upstream of the orifice for the same stoichiometric mixture. Computer simulations by Chorin's Random Vortex Method implemented with the flame propagation algorithm for the theoretical model of turbulent jets with and without combustion were performed to study the turbulent jet flow field. In the formation processes of the turbulent jets, the large-scale eddy structure of turbulence, the so-called coherent structure, dominates the entrainment and mixing processes. The large-scale eddy structure of turbulent jets in this study is constructed by a series of vortex pairs, which are organized in the form of a staggered array of vortex clouds generating local recirculation flow patterns.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-168139 , DOE/NASA/0131-1 , NAS 1.26:168139
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    Blade loss transient dynamic analysis of turbomachinery (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Previously cited in issue 17, p. 2687, Accession no. A82-34982
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: (ISSN 0001-1452)
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    The feasibility of water injection into the turbine coolant to permit gas turbine contingency power for helicopter application (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: It is pointed out that in certain emergency situations it may be desirable to obtain power from a helicopter engine at levels greater than the maximum rating. Yost (1976) has reported studies concerning methods of power augmentation in the one engine inoperative (OEI) case. It was found that a combination of water/alcohol injection into the inlet and overtemperature/overspeed could provide adequate emergency power. The present investigation is concerned with the results of a feasibility study which analytically investigated the maximum possible level of augmentation with constant gas generator turbine stress rupture life as a constraint. In the proposed scheme, the increased engine output is obtained by turbine overtemperature, however, the temperature of the compressor bleed air used for hot section cooling is lowered by injecting and evaporating water.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: ASME PAPER 83-GT-66 , (ISSN 0022-0825)
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    Computed and measured turbulence in axisymmetric reciprocating engines (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The turbulent flowfield of a spark-ignition engine affects strongly the combustion characteristics of the engine. The flowfield depends on the design of the combustion chamber and the intake system. The present investigation is concerned with the effect of chamber design, and engine operating conditions on top dead center turbulence prior to ignition. It is shown that many of the trends which were identified in earlier studies can be obtained from a single model. The employed model takes into account a two-dimensional axisymmetric flowfield. Attention is given to governing equations, boundary and initial conditions, a comparison of the computed results with measurements, and the effect of swirl and squish.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA Journal; 21; Apr. 198
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    Friction damping of flutter in gas turbine engine airfoils (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: This paper investigates the feasibility of using blade-to-ground friction dampers to stabilize flutter in blades. The response of an equivalent one mode model in which the aerodynamic force is represented as negative viscous damping is examined to investigate the following issues: the range of amplitudes over which friction damping can stabilize the response, the maximum negative aerodynamic damping that can be stabilized in such a manner, the effect of simultaneous resonant excitation on these stability limits, and the determination of those damper parameters which will be the best for flutter control.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Journal of Aircraft; 20; Apr. 198
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    Study of advanced rotary combustion engines for commuter aircraft (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Performance, weight, size, and maintenance data for advanced rotary aircraft engines suitable for comparative commuter aircraft system evaluation studies of alternate engine candidates are provided. These are turbocharged, turbocompounded, direct injected, stratified charge rotary engines. Hypothetical engines were defined (an RC4-74 at 895 kW and an RC6-87 at 1490 kW) based on the technologies and design approaches used in the highly advanced engine of a study of advanced general aviation rotary engines. The data covers the size range of shaft power from 597 kW (800 hp) to 1865 kW (2500 hp) and is in the form of drawings, tables, curves and written text. These include data on internal geometry and configuration, installation information, turbocharging and turbocompounding arrangements, design features and technologies, engine cooling, fuels, scaling for weight size BSFC and heat rejection for varying horsepower, engine operating and performance data, and TBO and maintenance requirements. The basic combustion system was developed and demonstrated; however the projected power densities and performance efficiencies require increases in engine internal pressures, thermal loading, and rotative speed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-165399 , NAS 1.26:165399 , CW-WR-81-022F
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    Effect of flameholder pressure drop on emissions and performance of premixed-prevaporized combustors (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Parametric tests were conducted to determine the effects of flameholder pressure drop on the emissions and performance of lean premixed-prevaporized combustors. A conical flameholder mounted in a diverging duct was tested with two values of flameholder blockage. Emissions of nitrogen oxides, carbon monoxide, carbon dioxide, and unburned hydrocarbons were measured for combustor entrance conditions of 600 to 800 K air temperature, 0.3 MPa to 0.5 MPa pressure, and 20 m/sec to 35 m/sec reference velocity. Jet A fuel was injected at flow rates corresponding to an equivalence ratio range from 0.8 down to the lean stability limit. Emission results for the high-blockage flameholder were a substantial improvement over the low-blockage emission results. A correlation of combustion efficiency with flameholder pressure drop was developed for pressure drops less than 9 percent.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TP-2131 , E-1358 , NAS 1.60:2131
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    Literature search of publications concerning the prediction of dynamic inlet flow distortion and related topics (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Publications prior to March 1981 were surveyed to determine inlet flow dynamic distortion prediction methods and to catalog experimental and analytical information concerning inlet flow dynamic distortion prediction methods and to catalog experimental and analytical information concerning inlet flow dynamics at the engine-inlet interface of conventional aircraft (excluding V/STOL). The sixty-five publications found are briefly summarized and tabulated according to topic and are cross-referenced according to content and nature of the investigation (e.g., predictive, experimental, analytical and types of tests). Three appendices include lists of references, authors, organizations and agencies conducting the studies. Also, selected materials summaries, introductions and conclusions - from the reports are included. Few reports were found covering methods for predicting the probable maximum distortion. The three predictive methods found are those of Melick, Jacox and Motycka. The latter two require extensive high response pressure measurements at the compressor face, while the Melick Technique can function with as few as one or two measurements.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-3673 , NAS 1.26:3673
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    Scaled centrifugal compressor, collector and running gear program (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The Scaled Centrifugal Compressor, Collector and Running gear Program was conducted in support of an overall NASA strategy to improve small-compressor performance, durability, and reliability while reducing initial and life-cycle costs. Accordingly, Garrett designed and provided a test rig, gearbox coupling, and facility collector for a new NASA facility, and provided a scaled model of an existing, high-performance impeller for evaluation scaling effects on aerodynamic performance and for obtaining other performance data. Test-rig shafting was designed to operate smoothly throughout a speed range up to 60,000 rpm. Pressurized components were designed to operate at pressures up to 300 psia and at temperatures to 1000 F. Nonrotating components were designed to provide a margin-of-safety of 0.05 or greater; rotating components, for a margin-of-safety based on allowable yield and ultimate strengths. Design activities were supported by complete design analysis, and the finished hardware was subjected to check-runs to confirm proper operation. The test rig will support a wide range of compressor tests and evaluations.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-168167 , NAS 1.26:168167 , GR-21-4269
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    Incidence loss for fan turbine rotor blade in two-dimensional cascade (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The effect of incidence angle on the aerodynamic performance of a fan turbine rotor blade was investigated experimentally in a two dimensional cascade. The test covered a range of incidence angles from -15 deg to 10 deg and exit ideal critical velocity ratios from 0.75 to 0.95. The principal measurements were blade-surface static pressures and cross-channel survey of exit total pressure, static pressure, and flow angle. Flow adjacent to surfaces was examined using a visualization technique. The results of the investigation include blade-surface velocity distribution and overall kinetic energy loss coefficients for the incidence angles and exit velocity ratios tested. The measured losses are compared with those from a reference core turbine rotor blade and also with two common analytical methods of predicting incidence loss.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TP-2188 , E-1587 , NAS 1.60:2188
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    Testing of felt-ceramic materials for combustor applications (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The feasibility of using composite felt ceramic materials as combustor liners was experimentally studied. The material consists of a porous felt pad sandwiched between a layer of ceramic and one of solid metal. Flat, rectangular test panels, which encompassed several design variations of the basic composite material, were tested, two at a time, in a premixed gas turbine combustor as sections of the combustor wall. Tests were conducted at combustor inlet conditions of 0.5 MPa and 533 K with a reference velocity of 25 m/s. The panels were subjected to a hot gas temperature of 2170 K with 1% of the total airflow used to film cool the ceramic surface of the test panel. In general, thin ceramic layers yield low ceramic stress levels with high felt ceramic interface temperatures. On the other hand, thick ceramic layers result in low felt ceramic interface temperatures but high ceramic stress levels. Extensive thermal cycling appears to cause material degradation, but for a limited number of cycles, the survivability of felt ceramic materials, even under extremely severe combustor operating conditions, was conclusively demonstrated.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-168103 , NAS 1.26:168103 , AD-A130069
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    Air modulation apparatus (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An air modulation apparatus, such as for use in modulating cooling air to the turbine section of a gas turbine engine is described. The apparatus includes valve means disposed around an annular conduit, such as a nozzle, in the engine cooling air circuit. The valve means, when in a closed position, blocks a portion of the conduit, and thus reduces the amount and increases the velocity of cooling air flowing through the nozzle. The apparatus also includes actuation means, which can operate in response to predetermined engine conditions, for enabling opening and closing of the valve means.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NAS 1.71:LEW-13524-1
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  • 87
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    Combustor liner construction (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A combustor liner is fabricated from a plurality of individual segments each containing counter/parallel Finwall material and are arranged circumferentially and axially to define the combustion zone. Each segment is supported by a hook and ring construction to an opened lattice frame with sufficient tolerance between the hook and ring to permit thermal expansion with a minimum of induced stresses.
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 88
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    V/STOL model fan stage rig design report (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A model single-stage fan with variable inlet guide vanes (VIGV) was designed to demonstrate efficient point operation while providing flow and pressure ratio modulation capability required for a V/STOL propulsion system. The fan stage incorporates a split-flap VIGV with an independently actuated ID flap to permit independent modulation of fan and core engine airstreams, a flow splitter integrally designed into the blade and vanes to completely segregate fan and core airstreams in order to maximize core stream supercharging for V/STOL operation, and an EGV with a variable leading edge fan flap for rig performance optimization. The stage was designed for a maximum flow size of 37.4 kg/s (82.3 lb/s) for compatibility with LeRC test facility requirements. Design values at maximum flow for blade tip velocity and stage pressure ratio are 472 m/s (1550 ft/s) and 1.68, respectively.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-174688 , NAS 1.26:174688 , PWA/GPD-FR-17826
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  • 89
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    Integrated flight/propulsion control system architectures for a high speed aircraft (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The present investigation is concerned with the impact of integrated flight, inlet, and engine control system architectures on system effectiveness and life cycle cost (LCC). The aircraft employed in the investigation is a modified YF-12 with a cruise Mach number of 2.5. The aircraft has two advanced technology aircraft JT-69 afterburning, low-bypass turbofan engines. Advanced technologies suitable for use in future flight/propulsion control systems are related to distributed computer networks, fault tolerant computers and software, analytical redundancy, self-checking microprocessor pairs, advanced direct drive actuators, fiber optic data buses, VLSI microcircuits, and skewed sensors. The integrated architectures were found to have fewer sensors, actuators, and power sources than the nonintegrated architectures.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 83-2563
    Format: text
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  • 90
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    The development of a generalized advanced propeller analysis system (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A Generalized Advanced Propeller Analysis System (GAPAS) is being developed to provide both an optimized design and a performance evaluation capability. The technology areas incorporated in GAPAS include propeller aerodynamic performance, airfoil loading, acoustics, structural analysis and aeroelasticity. The propeller analyses include the most advanced, fully-developed technologies in a modular but unified system. The program will treat multi-bladed propellers having straight or swept blades operating on aircraft at speeds to Mach 0.8 and altitudes to 40,000 feet. The purpose of this paper is twofold. First, it will introduce the GAPAS program to the general industry; and second, since the GAPAS program will be made available for general applications, it is also intended to be a status report on the development stage of the program.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 83-2466
    Format: text
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  • 91
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    Design concepts for low cost composite engine frames (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Design concepts for low-cost, lightweight composite engine frames were applied to the design requirements for the frame of commercial, high-bypass turbine engines. The concepts consist of generic-type components and subcomponents that could be adapted for use in different locations in the engine and to different engine sizes. A variety of materials and manufacturing methods were assessed with a goal of having the lowest number of parts possible at the lowest possible cost. The evaluation of the design concepts resulted in the identification of a hybrid composite frame which would weigh about 70 percent of the state-of-the-art metal frame and cost would be about 60 percent.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 83-2445
    Format: text
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  • 92
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    A design study of a reaction control system for a V/STOL fighter/attack aircraft (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Attention is given to a short takeoff vertical landing (STOVL) aircraft reaction control system (RCS) design study. The STOVL fighter/attack aircraft employs an existing turbofan engine, and its hover requirement places a premium on weight reduction, which eliminates prospective nonairbreathing RCSs. A simple engine compressor bleed RCS degrades overall performance to an unacceptable degree, and the supersonic requirement precludes the large volume alternatives of thermal or ejector thrust augmentation systems as well as the ducting of engine exhaust gases and the use of a dedicated turbojet. The only system which addressed performance criteria without requiring major engine modifications was a dedicated load compressor driven by an auxilliary power unit.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: ASME PAPER 83-GT-199
    Format: text
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  • 93
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    Status report - DARPA/NASA convertible turbofan/turboshaft engine program (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A development status report is presented for the NASA/Defense Advanced Research Projects Agency convertible turbofan-turboshaft engine, which can power a high speed rotorcraft in vertical flight, as well as in horizontal flight up to speeds of Mach 0.85. The basis for this development program is a modified TF34-GE-400 engine. Program objectives include both the demonstration of dual output mode (jet thrust and shaft horsepower) capability and the development of a control system which will operate the engine in either mode and convert operation between the modes.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: ASME PAPER 83-GT-196
    Format: text
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  • 94
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    Analysis of an axial compressor blade vibration based on wave reflection theory (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The paper describes application of the theory of wave reflection in turbomachines to rotor blade vibrations measured in an axial compressor stage. The blade vibrations analyzed could not be predicted using various flutter prediction techniques. The wave reflection theory, first advanced in 1966, is expanded, and more general equations for the rotor blade excitation frequencies are derived. The results of the analysis indicate that all examined rotor blade vibrations can be explained by forced excitations caused by reflecting waves (pressure pulses). Wave reflections between the rotor blades and both the upstream and downstream stator vanes had to be considered.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: ASME PAPER 83-GT-151
    Format: text
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  • 95
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    A vortex venturi for reverting antimisting fuel properties (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The level of degradation of antimisting fuel polymers such as FM-9 which must be accomplished in order to use antimisting fuel in existing engines may require the use of cavitation. The hydrodynamic shear produced by the collapse of vapor bubbles is capable of producing more splitting of polymeric molecules than mechanically-induced shear. A program has been carried out to investigate the possibility of using a cavitating venturi with rotating flow as a fuel reverter. This investigation included the effects of a swirl-inducing twisted tape upstream of the throat, inlet pressure, recovery pressure ratio and a pintle for varying throat area. A correlation of the data was produced, system concepts for using the vortex venturi were investigated and problem areas were delineated.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: ASME PAPER 83-GT-137
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  • 96
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    Dynamic distortion in a short s-shaped subsonic diffuser with flow separation (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: An experimental investigation of the time varying distortion at the diffuser exit of a subsonic HiMAT forebody and inlet was conducted at Mach 0.9 in the Lewis 8 by 6 foot Supersonic Wind Tunnel. A transitory separation was detected within the subsonic diffuser. Vortex generators were installed to eliminate the flow separation. Results from a study of the instantaneous pressure variations at the diffuser exit are presented. The time unsteady total pressures at the diffuser exit are computer interpolated and presented in the form of a movie showing the transitory separation. Limited data showing the instantaneous distortion levels are also presented. Previously announced in STAR as N83-26838
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 83-1412
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  • 97
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    Energy efficient engine. Fan and quarter-stage component performance report (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The fan configuration for the general Electric/NASA Energy Efficient Engine was selected following an extensive preliminary design study. The fan has an inlet radius ratio of 0.342 and a specific flowrate of 208.9 Kg/sec/sq. m (42.8 1bm/sec/sq. ft). The design corrected tip speed is 411.5 m/sec (1350 ft/sec) producing a bypass flow total-pressure ratio of 1.65 and a core flow total-pressure ratio of 1.6. The design bypass ratio is 6.8. The aerodynamic design point corresponds to the maximum climb power setting at Mach 0.8 and 10.67 Km (35,000 ft) altitude. The fully-instrumented fan component was tested in the Lynn Large Fan Test Facility in 1981. The overall performance results, reported herein, showed excellent fan performance with the fan meeting all of its component test goals of flow, efficiency and stall margin.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-168070 , NAS 1.26:168070 , R82AEB408
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  • 98
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    Component-specific modeling (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The overall objective of this program is to develop and verify a series of interdisciplinary modeling and analysis techniques which have been specialized to address three specific hot section components. These techniques will incorporate data as well as theoretical methods from many diverse areas, including cycle and performance analysis, heat transfer analysis, linear and nonlinear stress analysis, and mission analysis. Building on the proven techniques already available in these fields, the new methods developed through this contract will be integrated to provide an accurate, efficient, and unified approach to analyzing combustor burner liners, hollow air cooled turbine blades, and air cooled turbine vanes. For these components, the methods developed will predict temperature, deformation, stress, and strain histories throughout a complete flight mission.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center Turbine Eng. Hot Sect. Technol. (HOST); p 165-173
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  • 99
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    Rotorcraft convertible engine study (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Convertible propulsion systems for advanced rotorcraft are evaluated in terms of their impact on aircraft operating economics and fuel consumption. A variety of propulsion system concepts, including separate thrust and power producing engines, convertible fan/shaft engines, and auxiliary propeller configurations are presented. The merits of each are evaluated in two different rotorcraft missions: an intercity, commercial transport of the ABC(TM) type, and an offshore oil ring supply ship of the X-wing type. The variable inlet guide vane fan/shaft converting engine and auxiliary propeller configurations are shown to offer significant advantages over all the other systems evaluated, in terms of both direct operating cost and fuel consumption.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-168241 , NAS 1.26:168241 , R83AEB047
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  • 100
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    Energy Efficient Engine Program: Technology Benefit/Cost Study, Volume II (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The Benefit/Cost Study portion of the NASA-sponsored Energy Efficient Engine Component Development and Integration program was successful in achieving its objectives: identification of air transport propulsion system technology requirements for the years 2000 and 2010, and formulation of programs for developing these technologies. It is projected that the advanced technologies identified, when developed to a state of readiness, will provide future commercial and military turbofan engines with significant savings in fuel consumption and related operating costs. These benefits are significant and far from exhausted. The potential savings translate into billions of dollars in annual savings for the airlines. Analyses indicate that a significant portion of the overall savings is attributed to aerodynamic and structure advancements. Another important consideration in acquiring these benefits is developing a viable reference technology base that will permit engines to operate at substantially higher overall pressure ratios and bypass ratios. Results have pointed the direction for future research and a comprehensive program plan for achieving this was formulated. The next major step is initiating the program effort that will convert the advanced technologies into the expected benefits.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-174766-VOL-2 , NAS 1.26:174766-VOL-2 , PWA-5594-251-VOL-2
    Format: application/pdf
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