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  • Organic Chemistry  (6,916)
  • Cell & Developmental Biology  (6,711)
  • AIRCRAFT PROPULSION AND POWER
  • ddc:330
  • 2020-2024  (44)
  • 1985-1989  (9,368)
  • 1975-1979  (6,120)
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Year
  • 1
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    Frontiers in Chemistry: Rising Stars (2021)
    Frontiers Media SA
    Details
    Publication Date: 2024-04-04
    Description: The Frontiers in Chemistry Editorial Office team are delighted to present the inaugural “Frontiers in Chemistry: Rising Stars” article collection, showcasing the high-quality work of internationally recognized researchers in the early stages of their independent careers. All Rising Star researchers featured within this collection were individually nominated by the Journal’s Chief Editors in recognition of their potential to influence the future directions in their respective fields. The work presented here highlights the diversity of research performed across the entire breadth of the chemical sciences, and presents advances in theory, experiment and methodology with applications to compelling problems. This Editorial features the corresponding author(s) of each paper published within this important collection, ordered by section alphabetically, highlighting them as the great researchers of the future. The Frontiers in Chemistry Editorial Office team would like to thank each researcher who contributed their work to this collection. We would also like to personally thank our Chief Editors for their exemplary leadership of this article collection; their strong support and passion for this important, community-driven collection has ensured its success and global impact.
    Keywords: Green and Sustainable Chemistry ; Analytical Chemistry ; Theoretical and Computational Chemistry ; Polymer Chemistry ; Medicinal and Pharmaceutical Chemistry ; Organic Chemistry ; Nanoscience ; Catalysis and Photocatalysis ; Supramolecular Chemistry ; Electrochemistry ; Inorganic Chemistry ; Chemical Biology ; thema EDItEUR::P Mathematics and Science::PD Science: general issues
    Language: English
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    E-BOOK
  • 2
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    The direct approach to compensation of multivariable jet engine models (1985)
    In:  CASI
    Details
    Publication Date: 2009-11-23
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Alternatives for Jet Eng. Control. Vol. 1; p 36-37
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  • 3
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    Aircraft Energy Efficiency (ACEE) status report (1979)
    In:  CASI
    Details
    Publication Date: 2009-11-17
    Description: Fuel efficiency in aeronautics, for fuel conservation in general as well as for its effect on commercial aircraft operating economics is considered. Projects of the Aircraft Energy Efficiency Program related to propulsion are emphasized. These include: (1) engine component improvement, directed at performance improvement and engine diagnostics for prolonged service life; (2) energy efficient engine, directed at proving the technology base for the next generation of turbofan engines; and (3) advanced turboprop, directed at advancing the technology of turboprop powered aircraft to a point suitable for commercial airline service. Progress in these technology areas is reported.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion 1979; p 1-58
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  • 4
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    Nonlinear modeling of a turbofan jet engine: A tensor method application (1985)
    In:  CASI
    Details
    Publication Date: 2009-11-23
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Alternatives for Jet Eng. Control. Vol. 1; 220-221 (
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  • 5
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    An application of tensor ideas to nonlinear modeling of a turbofan jet engine (1985)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Alternatives for Jet Eng. Control. Vol. 1; p 201-210
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  • 6
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    Tensor ideas for nonlinear modeling of a turbofan jet engine: Preliminary studies (1985)
    In:  CASI
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    Publication Date: 2004-12-03
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Alternatives for Jet Eng. Control. Vol. 1; p 189-193
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  • 7
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    Graphics analysis of dominance in jet engine control models (1985)
    In:  CASI
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    Publication Date: 2009-11-23
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Alternatives for Jet Eng. Control. Vol. 1; p 19-21
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  • 8
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    High-performance-vehicle technology (1979)
    In:  CASI
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    Publication Date: 2006-07-16
    Description: Propulsion needs of high performance military aircraft are discussed. Inlet performance, nozzle performance and cooling, and afterburner performance are covered. It is concluded that nonaxisymmetric nozzles provide cleaner external lines and enhanced maneuverability, but the internal flows are more complex. Swirl afterburners show promise for enhanced performance in the high altitude, low Mach number region.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion 1979; p 445-462
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  • 9
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    Vertical Takeoff and Landing (VTOL) propulsion technology (1979)
    In:  CASI
    Details
    Publication Date: 2006-07-16
    Description: Propulsion problems and advanced technology requirements of VTOL aircraft are discussed. Specific topics covered include inlets with high angle of attack capability, rapid thrust modulation fans, and propulsion-system/aircraft-control integration.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion 1979; p 409-444
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  • 10
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    Hypersonic propulsion (1979)
    In:  CASI
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    Publication Date: 2006-07-16
    Description: Research on hydrogen fueled scramjet engines for hypersonic flight is reviewed. Component developments, computational methods, and preliminary ground tests of subscale scramjet engine modules at Mach 4 and 7 are emphasized. Airframe integration, structures, and flow diagnostics are also discussed. It is shown that mixed-mode perpendicular and parallel fuel injection controls heat release over a wide Mach range and the fixed geometry inlet gives good performance over a wide range of Mach numbers.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion 1979; p 387-408
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  • 11
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    Control technology (1979)
    In:  CASI
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    Publication Date: 2006-07-16
    Description: An overview of engine control technology is presented with emphasis on gas turbine engine controls. The role of the government, and NASA in particular, in advancing this technology is discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion 1979; p 329-344
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  • 12
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    Supersonic propulsion technology (1979)
    In:  CASI
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    Publication Date: 2006-07-16
    Description: Propulsion concepts for commercial supersonic transports are discussed. It is concluded that variable cycle engines, together with advanced supersonic inlets and low noise coannular nozzles, provide good operating performance for both supersonic and subsonic flight. In addition, they are reasonably quiet during takeoff and landing and have acceptable exhaust emissions.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion 1979; p 345-386
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  • 13
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    Mechanical components (1979)
    In:  CASI
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    Publication Date: 2006-07-16
    Description: Research on bearings, gears, seals, and rotor dynamics (specifically high speed balancing and dampers) is presented. The research pertains to problems in both aircraft turbine engines and helicopter transmissions.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion 1979; p 273-308
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  • 14
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    Instrumentation technology (1979)
    In:  CASI
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    Publication Date: 2006-07-16
    Description: Some of the efforts made in applying technologically new tools to today's propulsion measurement problems are described. They include: (1) a blade-tip clearance system; (2) a pulsed thermocouple system used to measure gas temperature with a thermocouple at temperatures above the melting point of the thermocouple; (3) an optical technique for measuring blade flutter; (4) a probe for dynamic flow and flow angle measurement; and (5) a laser anemometer system for rapidly mapping the flow profiles between the blades of a rotating compressor.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion 1979; p 309-328
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  • 15
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    Turbomachinery technology (1979)
    In:  CASI
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    Publication Date: 2006-07-16
    Description: A technology assessment of turbomachinery is presented. The design of the fan, compressor, and turbine components for future advanced aircraft engines is discussed. Basic flow characteristics in compressors and turbines and the heat transfer phenomena in cooled turbines are also discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion 1979; p 231-272
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  • 16
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    Computational fluid mechanics of internal flow (1979)
    In:  CASI
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    Publication Date: 2006-07-16
    Description: Major solution techniques for internal computational fluid mechanics are discussed and some examples are presented. The major steps involved in developing a large computer code are then discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion 1979; p 187-230
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  • 17
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    Alternative jet aircraft fuels (1979)
    In:  CASI
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    Publication Date: 2006-07-16
    Description: Potential changes in jet aircraft fuel specifications due to shifts in supply and quality of refinery feedstocks are discussed with emphasis on the effects these changes would have on the performance and durability of aircraft engines and fuel systems. Combustion characteristics, fuel thermal stability, and fuel pumpability at low temperature are among the factors considered. Combustor and fuel system technology needs for broad specification fuels are reviewed including prevention of fuel system fouling and fuel system technology for fuels with higher freezing points.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion 1979; p 129-148
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  • 18
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    Materials and structures technology (1979)
    In:  CASI
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    Publication Date: 2006-07-16
    Description: Materials and structures performance limitations, particularly for the hot section of the engine in which these limitations limit the life of components, are considered. Failure modes for components such as blades, vanes, and combustors and how they are affected by the environment for such components are discussed. Methods used to improve the materials used for such components are: (1) application of directional structures to turbine components for high strength at high temperatures; (2) improved coatings to increase oxidation and corrosion resistance; (3) increase strength and stiffness with reduced weight by applying higher specific properties of composite materials; and (4) cost effective processing such as near net shape powder methods applied to disks. Life prediction techniques developed to predict component life accurately in advance of service and progress in improving the intermediate and cold section components of turbine engines are covered.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion 1979; p 149-186
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  • 19
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    Noise reduction (1979)
    In:  CASI
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    Publication Date: 2006-07-16
    Description: The turbofan engine's noise-producing components are discussed in terms of efficient and economical noise reduction techniques that do not penalize the engine performance or weight significantly. Specific topics covered include fan noise, acoustic suppression, jet noise technology, combustor noise, and aircraft noise prediction.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion 1979; p 85-128
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  • 20
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    Emission reduction (1979)
    In:  CASI
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    Publication Date: 2006-07-16
    Description: Control of the gaseous pollutant emissions of aircraft engines is considered in terms of the emission standards for six classes of aircraft engines. Emphasis is placed on combustor design concepts to significantly reduce emissions levels and lean-burning techniques to lower flame temperature, to reduce the oxides of nitrogen in the gaseous emissions.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion 1979; p 59-84
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  • 21
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    Scheduled nonlinear control design for a turbojet engine (1985)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Alternatives for Jet Eng. Control. Vol. 1; p 185-188
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  • 22
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    CARDIAD approach to system dominance with application to turbofan engine models (1985)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Alternatives for Jet Eng. Control. Vol. 1; p 141-145
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  • 23
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    Optimal control of a supersonic inlet to minimize frequency of inlet unstart (1978)
    In:  CASI
    Details
    Publication Date: 2006-03-02
    Description: A preliminary investigation into the use of modern control theory for the design of controls for a supersonic inlet is described. In particular, the task of controlling a mixed-compression supersonic inlet is formulated as a linear optimal stochastic control and estimation problem. An inlet can exhibit an undesirable instability due to excessive inlet normal shock motion. For the optimal control formulation of the inlet problem, a non quadratic performance index, which is equal to the expected frequency of inlet unstarts, is used. This physically meaningful performance index is minimized for a range of inlet disturbance and measurement noise covariances.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA, Washington Fourth Inter-Center Control Systems Conf.; p 323-335
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  • 24
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    Aircraft engines (1977)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: Thrust and weight requirements of aircraft engines in general are discussed. The characteristics and operating principles of various types of air breathing and rocket engines are described.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Soviet Aircraft and Rockets (NASA-TT-F-770); p 81-139
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  • 25
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    Trends in aircraft noise control (1975)
    In:  CASI
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    Publication Date: 2006-01-11
    Description: Flight vehicles are characterized according to their manner of operation and type of propulsion system; and their associated sources of noise are identified. Available noise reduction technology as it relates to engine cycle design and to powerplant component design is summarized. Such components as exhaust jets, fans, propellers, rotors, blown flaps, and reciprocating-engine exhausts are discussed, along with their noise reduction potentials. Significant aircraft noise reductions are noted to have been accomplished by the application of available technology in support of noise certification rules. Further noise reductions to meet more stringent future noise regulations will require substantial additional technology developments. Improved analytical prediction methods, and well-controlled validation experiments supported by advanced-design aeroacoustic facilities, are required as a basis for an effective integrated systems approach to aircraft noise control.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA/Univ. Conf. on Aeron.; p 103-130
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  • 26
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    Normal shock and restart controls for a supersonic airbreathing propulsion system (1978)
    In:  CASI
    Details
    Publication Date: 2006-02-28
    Description: Results of experimental investigations to control a supersonic mixed-compression inlet coupled to a turbojet engine are presented. Special instrumentation and servoactuators were developed to have sufficiently fast dynamic response so that basic propulsion system dynamics were the main limitation to controllability. In some cases servoactuator input signals were electronically limited to simulate moderate performance flight hardware.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA, Washington Fourth Inter-Center Control Systems Conf.; p 299-321
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  • 27
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    Direct and system effects of water ingestion into jet engine compresors (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Water ingestion into aircraft-installed jet engines can arise both during take-off and flight through rain storms, resulting in engine operation with nearly saturated air-water droplet mixture flow. Each of the components of the engine and the system as a whole are affected by water ingestion, aero-thermally and mechanically. The greatest effects arise probably in turbo-machinery. Experimental and model-based results (of relevance to 'immediate' aerothermal changes) in compressors have been obtained to show the effects of film formation on material surfaces, centrifugal redistribution of water droplets, and interphase heat and mass transfer. Changes in the compressor performance affect the operation of the other components including the control and hence the system. The effects on the engine as a whole are obtained through engine simulation with specified water ingestion. The interest is in thrust, specific fuel consumption, surge margin and rotational speeds. Finally two significant aspects of performance changes, scalability and controllability, are discussed in terms of characteristic scales and functional relations.
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 28
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    Determination of compressor in-stall characteristics from engine surge transients (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Journal of Propulsion and Power (ISSN 0748-4658); 4; 133-143
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  • 29
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    Results of NASA's Energy Efficient Engine Program (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The major activity undertaken in the NASA Energy Efficient Engine Program has been completed. This paper reports on the progress made toward achieving the program goal of developing advanced technology to significantly reduce fuel consumption and operating costs of future subsonic transport-type propulsion systems. An additional goal was that the advanced concepts be compatible with future environmental regulations. Along with the results obtained, a brief overview of the design details of both the General Electric and Pratt and Whitney energy efficient engines and the overall program scope are presented. Overall, this program has been highly successful; the technology developed during its course is, and will continue to be, effectively employed in both current and future advance transport aircraft engine designs.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Journal of Propulsion and Power (ISSN 0748-4658); 3; 560-568
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  • 30
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    Compound cycle engine program (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The Compound Cycle Engine (CCE) is a highly turbocharged, power compounded power plant which combines the lightweight pressure rise capability of a gas turbine with the high efficiency of a diesel. When optimized for a rotorcraft, the CCE will reduce fuel burn for a typical 2 hr (plus 30 min reserve) mission by 30 to 40 percent when compared to a conventional advanced technology gas turbine. The CCE can provide a 50 percent increase in range-payload product on this mission. A program to establish the technology base for a Compound Cycle Engine is presented. The goal of this program is to research and develop those technologies which are barriers to demonstrating a multicylinder diesel core in the early 1990's. The major activity underway is a three-phased contract with the Garrett Turbine Engine Company to perform: (1) a light helicopter feasibility study, (2) component technology development, and (3) lubricant and material research and development. Other related activities are also presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 31
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    Pressure scaling effects in a scramjet combustion chamber (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The test results obtained for a model scramjet over a range of pressure levels corresponding to different flight altitudes involve enthalpies that vary from the ignition limit, at the low temperature end, to temperatures where the dissociation of combustion products severely limits heat release. The minimum temperature is noted to be highly pressure-sensitive; above the ignition limit, the amount of heat release increased markedly with pressure and with combustion chamber length. A FEM computer code has been used to model the mixing and combustion processes.
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 32
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    Aeroelastic control of stability and forced response of supersonic rotors by aerodynamic detuning (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Aerodynamic detuning, defined as designed passage-to-passage differences in the unsteady aerodynamic flow field of a rotor blade row, is a new approach to passive flutter and forced response control. In this paper, a mathematical model for aerodynamic detuning is developed and utilized to demonstrate the aeroelastic stability enhancement due to aerodynamic detuning of supersonic blade rows. In particular, a model is developed to analyze both the torsion mode and the coupled bending-torsion mode unstalled supersonic flutter and torsion mode aerodynamically forced response characteristics of an aerodynamically detuned rotor operating in a supersonic inlet flow field with a subsonic leading edge locus. As small solidity variations do not have a dominant effect on the steady-state performance of a rotor, the aerodynamic detuning mechanism considered is nonuniform circumferential spacing of adjacent blades.
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 33
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    Influence of third-degree geometric nonlinearities on the vibration and stability of pretwisted, preconed, rotating blades (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The governing coupled flapwise bending, edgewise bending, and torsional equations are derived including third-degree goemetric nonlinear elastic terms by making use of the geometric nonlinear theory of elasticity in which the elongations and shears are negligible compared to unity. These equations are specialized for blades of doubly symmetric cross section with linear variation of Pretwist over the blade length. The nonlinear steady state equations and the linearized perturbation equations are solved by using the Galerkin method, and by utilizing the nonrotating normal modes for the shape functions. Parametric results obtained for various cases of rotating blades from the present theoretical formulation are compared to those produced from the finite element code MSC/NASTRAN, and also to those produced from an in-house experimental test rig. It is shown that the spurious instabilities, observed for thin, rotating blades when second degree geometric nonlinearities are used, can be eliminated by including the third-degree elastic nonlinear terms. Furthermore, inclusion of third degree terms improves the correlation between the theory and experiment.
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 34
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    Design and evaluation of a new injector configuration for supersonic combustion (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Ignition and flameholding behavior data are presented from experiments with a novel scramjet injector configuration consisting of five small upstream pilot fuel injectors, a rearward-facing step, and three primary fuel injectors downstream of the step; all injection is perpendicular to the Mach 2 airflow, and the ignition source is located in the recirculation region downstream of the step. The design attempts to minimize the amount of igniter energy required for ignition, but without introduction of the large losses associated with bluff bodies. Argon plasma, argon-hydrogen plasma, pyrophoric silane/hydrogen, and surface-discharge ignition sources are tested. The injector is found to be able to hold flames at 1400 R total temperatures without the use of large bluff bodies; the argon-hydrogen plasma was the most effective igniter.
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 35
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    Hydrogen scramjet with sidewall injection - Shock tunnel simulations (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A free-piston shock tunnel has been used to obtain test data on a scramjet combustion chamber with sidewall injection. The results obtained indicate that combustion was strongly influenced by a region of fuel whose temperature was held below its ignition temperature by wall-cooling effects; this increased the fraction of unburned fuel and resulted in a significant loss of specific impulse. Aerodynamic heating would keep the walls above hydrogen ignition temperature in an actual scramjet powerplant, however. Maximum specific impulse was obtained with a combination of parallel and transverse injection in a long combustion chamber, followed by a dual stage expansion.
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 36
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    A real-time simulation evaluation of an advanced detection, isolation and accommodation algorithm for sensor failures in turbine engines (1986)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: An advanced sensor failure detection, isolation, and accommodation (ADIA) algorithm has been developed for use with an aircraft turbofan engine control system. In a previous paper the authors described the ADIA algorithm and its real-time implementation. Subsequent improvements made to the algorithm and implementation are discussed, and the results of an evaluation presented. The evaluation used a real-time, hybrid computer simulation of an F100 turbofan engine.
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 37
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    Forced response analysis of an aerodynamically detuned supersonic turbomachine rotor (1985)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The effect of aerodynamic detuning on the supersonic flow induced forced response behavior of a turbomachine blade row is analyzed using an aeroelastic model. The rotor is modeled as a flat plate airfoil cascade representing an unwrapped rotor annulus; the aerodynamic detuning is achieved by alternating the circumferential spacing of adjacent rotor blades. The total unsteady aerodynamic loading on the blading, due to the convection of the transverse gust past the airfoil cascade as well as that resulting from the motion of the cascade, is developed in terms of influence coefficients. The model developed here is then used to analyze the effect of aerodynamic detuning on the flow induced forced response behavior of a twelve-bladed rotor with Verdon's Cascade B flow geometry.
    Keywords: AIRCRAFT PROPULSION AND POWER
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    Analytical determination of propeller performance degradation due to ice accretion (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A computer code capable of computing the propeller performance for clean, glaze, or rime ice propeller configurations to determine the performance degradation resulting from a given icing encounter has been developed. The inviscid, incompressible flowfield at each specified propeller radial location is first computed using the Theodorsen method. A droplet trajectory computation then calculates the droplet impingement points and airfoil collection efficiency for each radial location. User-selectable empirical correlations are available for determining the aerodynamic penalties due to ice accretion. Propeller performance is finally computed using strip analysis for either the clean or iced propeller. In the iced mode, the thrust and torque coefficient equations are modified by the drag and lift coefficient increments due to ice to obtain the appropriate iced values. Comparison with available experimental propeller icing data shows generally good agreement. The code's capability of properly predicting the thrust coefficient, power coefficient, and propeller efficiency of an iced propeller is shown to be dependent on the choice of empirical correlation employed as well as on the proper specification of the radial icing extent and propeller blade angle.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Journal of Aircraft (ISSN 0021-8669); 24; 768-775
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  • 39
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    Mixing augmentation technique for hypervelocity scramjets (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Journal of Propulsion and Power (ISSN 0748-4658); 5; 514-522
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  • 40
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    Contingency power for small turboshaft engines (1989)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Journal of Propulsion and Power (ISSN 0748-4658); 5; 103-108
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  • 41
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    Development of an analytical model to assess fuel property effects on combustor performance (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A generalized first-order computer model has been developed in order to analytically evaluate the potential effect of alternative fuels' effects on gas turbine combustors. The model assesses the size, configuration, combustion reliability, and durability of the combustors required to meet performance and emission standards while operating on a broad range of fuels. Predictions predicated on combustor flow-field determinations by the model indicate that fuel chemistry, as defined by hydrogen content, exerts a significant influence on flame retardation, liner wall temperature, and smoke emission.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: International Journal of Turbo and Jet-Engines (ISSN 0334-0082); 4; 3-4,
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  • 42
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    Control of rotor aerodynamically forced vibrations by splitters (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Journal of Propulsion and Power (ISSN 0748-4658); 4; 445-451
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  • 43
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    An overview of rotorcraft propulsion research at Lewis Research Center (1988)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Rotorcraft propulsion research at Lewis Research Center is discussed, stressing programs in four areas of component research: compressors, combustors, turbines and transmissions, and three developmental programs: the Small Turboshaft Engine Research (STER) Project, the Advanced Rotorcraft Transmission (ART) program, and the Compound Cycle Engine (CCE) program. The component research emphasizes special problems of turboshaft engines in the 5 lb/sec to 30 lb/sec range. The objectives of the STER program are to evaluate the application of advanced concepts to small turboshaft engine systems and to investigate system related phenomena, such as distortion effects and secondary flow phenomena. The goals of the ART program are to reduce transmission weight by 25 percent, noise generation by 10 dB and mean time between removal to 5,000 hrs. The CCE program is working to combine the airflow capacity and light-weight features of a gas turbine with the more efficient, but heavier diesel turbine.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Vertiflite (ISSN 0042-4455); 34; 24-31
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  • 44
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    An application of tensor ideas to nonlinear modeling of a turbofan jet engine (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Alternatives for Jet Engine Control, Vol. 2; p 92-101
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  • 45
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    Nonlinear modeling of a turbofan jet engine: A tensor method application (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Alternatives for Jet Engine Control, Vol. 2; p 90-91
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  • 46
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    Predicted changes in advanced turboprop noise with shaft angle of attack (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Journal of Propulsion and Power (ISSN 0748-4658); 1; 381-387
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  • 47
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    Vibration and flutter of mistuned bladed-disk assemblies (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Journal of Propulsion and Power (ISSN 0748-4658); 1; 336-344
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  • 48
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    New evidence of the mechanisms of noise generation and radiation of a subsonic jet (1975)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Acoustical Society of America; vol. 57
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  • 49
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    Streamtube analysis of a hydrogen-burning scramjet exhaust and simulation technique (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A scramjet/airframe integration program and a technique for simulating thermally perfect scramjet exhaust flows (freon/argon gas blends) is studied to extend the technique to more complicated flows approaching the actual exhaust flow in complexity. The state of the flow and the accuracy of the substitute gas simulation are analyzed in the case of a shock discontinuity present. Findings are: scramjet exhaust flow is essentially frozen throughout the expansion at Mach 6 and Mach 8; flow behind moderate shocks remains frozen; the technique can accurately track static distributions in scramjet exhaust flows (shocked or unshocked).
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Journal of Aircraft; 14; Sept
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  • 50
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    Procedures for shape optimization of gas turbine disks (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Two procedures, the feasible direction method and sequential linear programming, for shape optimization of gas turbine disks are presented. The objective of these procedures is to obtain optimal designs of turbine disks with geometric and stress constraints. The coordinates of the selected points on the disk contours are used as the design variables. Structural weight, stress and their derivatives with respect to the design variables are calculated by an efficient finite element method for design senitivity analysis. Numerical examples of the optimal designs of a disk subjected to thermo-mechanical loadings are presented to illustrate and compare the effectiveness of these two procedures.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Langley Research Center, Recent Advances in Multidisciplinary Analysis and Optimization, Part 3; p 1097-1108
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  • 51
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    Life modeling of thermal barrier coatings for aircraft gas turbine engines (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Thermal barrier coating life models developed under the NASA Lewis Research Center's Hot Section Technology (HOST) Program are summarized. An initial laboratory model and three design-capable models are discussed. Current understanding of coating failure mechanisms are also summarized. The materials and structural aspects of thermal barrier coatings have been successfully integrated under the HOST program to produce models which may now or in the near future be used in design. Efforts on this program continue at Pratt and Whitney Aircraft where their model is being extended to the life prediction of physical vapor deposited thermal barrier coatings.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Toward Improved Durability in Advanced Aircraft Engine Hot Sections; p 109-115
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  • 52
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    Assessment, development, and application of combustor aerothermal models (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The gas turbine combustion system design and development effort is an engineering exercise to obtain an acceptable solution to the conflicting design trade-offs between combustion efficiency, gaseous emissions, smoke, ignition, restart, lean blowout, burner exit temperature quality, structural durability, and life cycle cost. For many years, these combustor design trade-offs have been carried out with the help of fundamental reasoning and extensive component and bench testing, backed by empirical and experience correlations. Recent advances in the capability of computational fluid dynamics codes have led to their application to complex 3-D flows such as those in the gas turbine combustor. A number of U.S. Government and industry sponsored programs have made significant contributions to the formulation, development, and verification of an analytical combustor design methodology which will better define the aerothermal loads in a combustor, and be a valuable tool for design of future combustion systems. The contributions made by NASA Hot Section Technology (HOST) sponsored Aerothermal Modeling and supporting programs are described.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Toward Improved Durability in Advanced Aircraft Engine Hot Sections; p 23-37
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  • 53
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    Supersonic throughflow fans (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Supersonic throughflow fan research, and technology needs are reviewed. The design of a supersonic throughflow fan stage, a facility inlet, and a downstream diffuser is described. The results from the analysis codes used in executing the design are shown. An engine concept intended to permit establishing supersonic throughflow within the fan on the runway and maintaining the supersonic throughflow condition within the fan throughout the flight envelope is presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Von Karman Institute for Fluid Dynamics, Transonic Compressors, Volume 2; 30 p
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  • 54
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    The design and development of transonic multistage compressors (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The development of the transonic multistage compressor is reviewed. Changing trends in design and performance parameters are noted. These changes are related to advances in compressor aerodynamics, computational fluid mechanics and other enabling technologies. The parameters normally given to the designer and those that need to be established during the design process are identified. Criteria and procedures used in the selection of these parameters are presented. The selection of tip speed, aerodynamic loading, flowpath geometry, incidence and deviation angles, blade/vane geometry, blade/vane solidity, stage reaction, aerodynamic blockage, inlet flow per unit annulus area, stage/overall velocity ratio, and aerodynamic losses are considered. Trends in these parameters both spanwise and axially through the machine are highlighted. The effects of flow mixing and methods for accounting for the mixing in the design process are discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Von Karman Institute for Fluid Dynamics, Transonic Compressors, Volume 2; 97 p
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  • 55
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    Fatigue life prediction modeling for turbine hot section materials (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A major objective of the fatigue and fracture efforts under the NASA Hot Section Technology (HOST) program was to significantly improve the analytic life prediction tools used by the aeronautical gas turbine engine industry. This was achieved in the areas of high-temperature thermal and mechanical fatigue of bare and coated high-temperature superalloys. The cyclic crack initiation and propagation resistance of nominally isotropic polycrystalline and highly anisotropic single crystal alloys were addressed. Life prediction modeling efforts were devoted to creep-fatigue interaction, oxidation, coatings interactions, multiaxiality of stress-strain states, mean stress effects, cumulative damage, and thermomechanical fatigue. The fatigue crack initiation life models developed to date include the Cyclic Damage Accumulation (CDA) and the Total Strain Version of Strainrange Partitioning (TS-SRP) for nominally isotropic materials, and the Tensile Hysteretic Energy Model for anisotropic superalloys. A fatigue model is being developed based upon the concepts of Path-Independent Integrals (PII) for describing cyclic crack growth under complex nonlinear response at the crack tip due to thermomechanical loading conditions. A micromechanistic oxidation crack extension model was derived. The models are described and discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Toward Improved Durability in Advanced Aircraft Engine Hot Sections; p 97-107
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  • 56
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    Structural analysis methods development for turbine hot section components (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The structural analysis technologies and activities of the NASA Lewis Research Center's gas turbine engine HOT Section Technoloogy (HOST) program are summarized. The technologies synergistically developed and validated include: time-varying thermal/mechanical load models; component-specific automated geometric modeling and solution strategy capabilities; advanced inelastic analysis methods; inelastic constitutive models; high-temperature experimental techniques and experiments; and nonlinear structural analysis codes. Features of the program that incorporate the new technologies and their application to hot section component analysis and design are described. Improved and, in some cases, first-time 3-D nonlinear structural analyses of hot section components of isotropic and anisotropic nickel-base superalloys are presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Toward Improved Durability in Advanced Aircraft Engine Hot Sections; p 57-82
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    NASA HOST project overview (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: NASA's Hot Section Technology (HOST) program has developed improved analytical models for the aerothermal environment, thermomechanical loading, material behavior, structural response, and service life of aircraft gas turbine engines' hot section components. These models, in conjunction with sophisticated computer codes, can be used in design analyses of critical combustor and turbine elements. Toward these ends, efforts were undertaken in instrumentation, combustion, turbine heat transfer, structural analysis, fatigue-fracture, and surface protection. Attention is presently given to the organization of HOST activities and their specific subject matter.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Toward Improved Durability in Advanced Aircraft Engine Hot Sections; p 1-4
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    HOST turbine heat transfer subproject overview (1986)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The experimental part of the turbine heat transfer subproject consists of six large experiments, which are highlighted in this overview, and three of somewhat more modest scope. One of the initial efforts was the stator airfoil heat transfer program. The non-film cooled and the showerhead film cooled data have already been reported. The gill region film cooling effort is currently underway. The investigation of secondary flows in a 90 deg curved duct, was completed. The first phase examined flows with a relatively thin inlet boundary layer and low free stream turbulence. The second phase studied a thicker inlet boundary layer and higher free stream turbulence. A comparison of analytical and experimental cross flow velocity vectors is shown for the 60 deg plane. Two experiments were also conducted in the high pressure facility. One examined full coverage film cooled vanes, and the other, advanced instrumentation. The other three large experimental efforts were conducted in a rotation reference frame. An experiment to obtain gas path airfoil heat transfer coefficients in the large, low speed turbine was completed. Single-stage data with both high and low-inlet turbulence were taken. The second phase examined a one and one-half stage turbine and focused on the second vane row. Under phase 3 aerodynamic quantities such as interrow time-averaged and rms values of velocity, flow angle, inlet turbulence, and surface pressure distribution were measured.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Turbine Engine Hot Section Technology 1986; p 13-17
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    HOST instrumentation R and D program overview (1986)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The HOST Instrumentation R and D program is focused on two categories of instrumentation. One category is that required to characterize the environment imposed on the hot section components of turbine engines. This category includes instruments for measuring gas flow, gas temperature, and heat flux. The second category is that for measuring the effect of the environment on the hot section components. This category includes strain measuring instruments and an optical system for viewing the interior of an operating combustor to detect cracks, buckling, carbon buildup, etc.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Turbine Engine Hot Section Technology 1986; p 7-8
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    Turbine Engine Hot Section Technology (HOST) Project (1986)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The Hot Section Technology (HOST) Project is a NASA-sponsored endeavor to improve the durability of advanced gas turbine engines for commercial and military aircraft. Through improvements in the analytical models and life prediction systems, designs for future hot section components, the combustor and turbine, will be more accurately analyzed and will incorporate features required for longer life in the more hostile operating environment of high performance engines.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Turbine Engine Hot Section Technology 1986; p 1-6
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    HOST combustion R and T overview (1986)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The overall objective of the Turbine Engine Hot Section Technology Combustion Project was to develop and verify improved and more accurate numerical analysis methods for increasing the ability to design with confidence combustion systems for advanced aircraft gas turbine engines. The objective was approached from two directions: computational and experimental. On the computational side, the approach was to first assess and evaluate existing combustor aerothermal analysis models. On the experimental side, three types of experiments are identified; first, fundamental experiments directed toward improved understanding of the flow physics and chemistry; second, experiments run to provide data for the empirical modeling of complex phenomena; and third, benchmark experiments for computer code validation.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Turbine Engine Hot Section Technology 1986; p 9-11
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  • 62
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    Fretting in aircraft turbine engines (1975)
    In:  CASI
    Details
    Publication Date: 2012-05-22
    Description: The problems created by fretting in turbine engines are discussed. The areas of greatest wear identified with the fan, compressor, and turbine blade mountings being the most critical items. Various methods for reducing or eliminating fretting in a turbine engine are described. Vacuum deposition of coatings by sputtering and ion plating are recommended as an economic method of applying thin films to inhibit fretting.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AGARD Specialists Meeting on Fretting in Aircraft Systems; 17 p
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  • 63
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    Aeroacoustics: Jet noise, combustion and core engine noise (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The papers in this volume deal essentially with the question whether the amplification of noise is due to the jet noise phenomenon or perhaps an interaction of airframe and core engine noise. In the area of jet noise suppression, various promising suppressor concepts are examined. The swirling flow jet noise suppressor is shown to provide significant noise reduction with minimal thrust losses. Progress in the aircraft engine core noise problem is reflected by seven research-type papers. Two possible mechanisms are seen to be responsible for core noise. One is the direct noise radiated from the turbulent combustion in the primary combuster and transmitted through the turbine, passing out the nozzle into the far field. The other mechanism is the noise that is emitted from hot spots being convected through the turbine. Which of these mechanisms (or perhaps both mechanisms) is responsible for core noise, and what are the coupling mechanisms of core engine noise and jet noise are the questions confronting researchers.
    Keywords: AIRCRAFT PROPULSION AND POWER
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    How good is jet lift VTOL technology (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The status of technologies for jet-lift V/STOL aircraft is examined, and a critical review of the performance of jet-lift VTOL aircraft built to date is made. Most jet-lift aircraft have suffered from adverse propulsion-induced effects during takeoff and landing. Flight dynamics of jet-lift aircraft have suffered from shortcomings in static and dynamic stability, control characteristics, and flight path control. Some of the main problems to be considered during the selection of a propulsion system arrangement for a V/STOL fighter are discussed. At present, experimental and analytical data on supersonic V/STOL configurations are insufficient to permit evaluating propulsion system arrangements.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Astronautics and Aeronautics; 15; Dec. 197
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    Views on the impact of HOST (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The Hot Section Technology (HOST) Project, which was initiated by NASA Lewis Research Center in 1980 and concluded in 1987, was aimed at improving advanced aircraft engine hot section durability through better technical understanding and more accurate design analysis capability. The project was a multidisciplinary, multiorganizational, focused research effort that involved 21 organizations and 70 research and technology activities and generated approximately 250 research reports. No major hardware was developed. To evaluate whether HOST had a significant impact on the overall aircraft engine industry in the development of new engines, interviews were conducted with 41 participants in the project to obtain their views. The summarized results of these interviews are presented. Emphasis is placed on results relative to three-dimensional inelastic structural analysis, thermomechanical fatigue testing, constitutive modeling, combustor aerothermal modeling, turbine heat transfer, protective coatings, computer codes, improved engine design capability, reduced engine development costs, and the impacts on technology transfer and the industry-government partnership.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Toward Improved Durability in Advanced Aircraft Engine Hot Sections; p 117-123
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    Structural analysis applications (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: An account is given of the application of computer codes for the efficient conduct of three-dimensional inelastic analyses to aircraft gas turbine combustor, turbine blade, and turbine stator vane components. The synergetic consequences of the program's activities are illustrated by an evaluation of the computer analyses of thermal barrier coatings and of the Space Shuttle Main Engine's High Pressure Fuel Turbopump turbine blading. This software, in conjunction with state-of-the-art supercomputers, can significantly reduce design-task burdens.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA, Lewis Research Center, Toward Improved Durability in Advanced Aircraft Engine Hot Sections; p 83-95
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    Review and assessment of the database and numerical modeling for turbine heat transfer (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The objectives of the NASA Hot Section Technology (HOST) Turbine Heat Transfer subproject were to obtain a better understanding of the physics of the aerothermodynamic phenomena and to assess and improve the analytical methods used to predict the flow and heat transfer in high-temperature gas turbines. At the time the HOST project was initiated, an across-the-board improvement in turbine design technology was needed. A building-block approach was utilized and the research ranged from the study of fundamental phenomena and modeling to experiments in simulated real engine environments. Experimental research accounted for approximately 75 percent of the funding while the analytical efforts were approximately 25 percent. A healthy government/industry/university partnership, with industry providing almost half of the research, was created to advance the turbine heat transfer design technology base.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Toward Improved Durability in Advanced Aircraft Engine Hot Sections; p 39-55
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  • 68
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    Advanced high temperature instrument for hot section research applications (1989)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Programs to develop research instrumentation for use in turbine engine hot sections are described. These programs were initiated to provide improved measurements capability as support for a multidisciplinary effort to establish technology leading to improved hot section durability. Specific measurement systems described here include heat flux sensors, a dynamic gas temperature measuring system, laser anemometry for hot section applications, an optical system for viewing the interior of a combustor during operation, thin film sensors for surface temperature and strain measurements, and high temperature strain measuring systems. The state of development of these sensors and measuring systems is described, and, in some cases, examples of measurements made with these instruments are shown. Work done at the NASA Lewis Research Center and at various contract and grant facilities is covered.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Toward Improved Durability in Advanced Aircraft Engine Hot Sections; p 5-21
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    Unsteady aerodynamics of blade rows (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The requirements placed on an unsteady aerodynamic theory intended for turbomachinery aeroelastic or aeroacoustic applications are discussed along with a brief description of the various theoretical models that are available to address these requirements. The major emphasis is placed on the description of a linearized inviscid theory which fully accounts for the affects of a nonuniform mean or steady flow on unsteady aerodynamic response. Although this linearization was developed primarily for blade flutter prediction, more general equations are presented which account for unsteady excitations due to incident external aerodynamic disturbances as well as those due to prescribed blade motions. The motivation for this linearized unsteady aerodynamic theory is focused on, its physical and mathematical formulation is outlined and examples are presented to illustrate the status of numerical solution procedures and several effects of mean flow nonuniformity on unsteady aerodynamic response.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA, Langley Research Center, Transonic Unsteady Aerodynamics and Aeroelasticity 1987, Part 2; p 605-630
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    Transonic propulsion system integration analysis at McDonnell Aircraft Company (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The technology of Computational Fluid Dynamics (CFD) is becoming an important tool in the development of aircraft propulsion systems. Two of the most valuable features of CFD are: (1) quick acquisition of flow field data; and (2) complete description of flow fields, allowing detailed investigation of interactions. Current analysis methods complement wind tunnel testing in several ways. Herein, the discussion is focused on CFD methods. However, aircraft design studies need data from both CFD and wind tunnel testing. Each approach complements the other.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA, Langley Research Center, Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 2; p 409-436
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  • 71
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    Turbomachinery aeroelasticity at NASA Lewis Research Center (1989)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The turbomachinery aeroelastic effort is focused on unstalled and stalled flutter, forced response, and whirl flutter of both single rotation and counter rotation propfans. It also includes forced response of the Space Shuttle Main Engine (SSME) turbopump blades. Because of certain unique features of propfans and the SSME turbopump blades, it is not possible to directly use the existing aeroelastic technology of conventional propellers, turbofans or helicopters. Therefore, reliable aeroelastic stability and response analysis methods for these propulsion systems must be developed. The development of these methods for propfans requires specific basic technology disciplines, such as 2-D and 3-D steady and unsteady aerodynamic theories in subsonic, transonic and supersonic flow regimes; modeling of composite blades; geometric nonlinear effects; and passive and active control of flutter and response. These methods are incorporated in a computer program, ASTROP. The program has flexibility such that new and future models in basic disciplines can be easily implemented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA, Langley Research Center, Transonic Unsteady Aerodynamics and Aeroelasticity 1987, Part 2; p 571-603
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  • 72
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    Review and assessment of the HOST turbine heat transfer program (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The objectives of the HOST Turbine Heat Transfer subproject were to obtain a better understanding of the physics of the aerothermodynamic phenomena occurring in high-performance gas turbine engines and to assess and improve the analytical methods used to predict the fluid dynamics and heat transfer phenomena. At the time the HOST project was initiated, an across-the-board improvement in turbine design technology was needed. Therefore, a building-block approach was utilized, with research ranging from the study of fundamental phenomena and analytical modeling to experiments in simulated real-engine environments. Experimental research accounted for 75 percent of the project, and analytical efforts accounted for approximately 25 percent. Extensive experimental datasets were created depicting the three-dimensional flow field, high free-stream turbulence, boundary-layer transition, blade tip region heat transfer, film cooling effects in a simulated engine environment, rough-wall cooling enhancement in a rotating passage, and rotor-stator interaction effects. In addition, analytical modeling of these phenomena was initiated using boundary-layer assumptions as well as Navier-Stokes solutions.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Lewis Structures Technology, 1988. Volume 3: Structural Integrity Fatigue and Fracture Wind Turbines HOST; p 349-367
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  • 73
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    Computational structural mechanics for engine structures (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The computational structural mechanics (CSM) program at Lewis encompasses the formulation and solution of structural mechanics problems and the development of integrated software systems to computationally simulate the performance, durability, and life of engine structures. It is structured to supplement, complement, and, whenever possible, replace costly experimental efforts. Specific objectives are to investigate unique advantages of parallel and multiprocessing for reformulating and solving structural mechanics and formulating and solving multidisciplinary mechanics and to develop integrated structural system computational simulators for predicting structural performance, evaluating newly developed methods, and identifying and prioritizing improved or missing methods.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Lewis Structures Technology, 1988. Volume 2: Structural Mechanics; p 189-203
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  • 74
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    The composite blade structural analyzer (COBSTRAN) (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The use and application of the COBSTRAN (COmposite Blade STRuctural ANalyzer) computer code is presented. COBSTRAN was developed at NASA-Lewis and is currently being used for the design and analysis of aircraft engine ducted and unducted fan blades. The features of COBSTRAN are demonstrated for the modeling and analysis of a scaled down wind tunnel model propfan blade made from fiber composites. Comparison of analytical and experimental mode shapes and frequencies are shown, verifying the model development and analysis techniques used. The methodologies and programs developed for this analysis are directly applicable to other propfan blades.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Lewis Structures Technology, 1988. Volume 2: Structural Mechanics; p 83-97
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  • 75
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    High-temperature combustor liner tests in structural component response test facility (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Jet engine combustor liners were tested in the structural component response facility at NASA Lewis. In this facility combustor liners were thermally cycled to simulate a flight envelope of takeoff, cruise, and return to idle. Temperatures were measured with both thermocouples and an infrared thermal imaging system. A conventional stacked-ring louvered combustor liner developed a crack at 1603 cycles. This test was discontinued after 1728 cycles because of distortion of the liner. A segmented or float wall combustor liner tested at the same heat flux showed no significant change after 1600 cycles. Changes are being made in the facility to allow higher temperatures.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Lewis Structures Technology, 1988. Volume 2: Structural Mechanics; p 5-13
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  • 76
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    Analysis and performance prediction of scramjet inlets utilizing a three-dimensional Navier-Stokes code (1986)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A series of inlet analysis codes (2-D, axisymmetric, 3-D) were developed which can analyze complicated flow through complex inlet geometries in a reasonably efficient manner. The codes were verified and are being used extensively to analyze practical inlet geometries both at Langley as well as industries. Newly installed VPS 32 computer will allow more complex configurations to be analyzed. Scalar FORTRAN versions are available to increase transportability of the codes for use on other Scalar computers and on the Cray vector processing computer.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Langley Symposium on Aerodynamics, Volume 1; p 187-208
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  • 77
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    Application of CFD codes to the design and development of propulsion systems (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The internal flows of aerospace propulsion engines have certain common features that are amenable to analysis through Computational Fluid Dynamics (CFD) computer codes. Although the application of CFD to engineering problems in engines was delayed by the complexities associated with internal flows, many codes with different capabilities are now being used as routine design tools. This is illustrated by examples taken from the aircraft gas turbine engine of flows calculated with potential flow, Euler flow, parabolized Navier-Stokes, and Navier-Stokes codes. Likely future directions of CFD applied to engine flows are described, and current barriers to continued progress are highlighted. The potential importance of the Numerical Aerodynamic Simulator (NAS) to resolution of these difficulties is suggested.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Ames Research Center, Supercomputing in Aerospace; p 139-148
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  • 78
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    Hot gas ingestion: From model results to full scale engine testing (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: An overview is presented of a joint NASA Lewis McDonnell Aircraft Co. Hot Gas Ingestion (HGI) test program in NASA Lewis' 9 x 15 foot Low Speed Wind Tunnel (LSWT). Advanced short takeoff vertical landing (ASTOVL) aircraft capable of operating from remote sites, damaged runways, aircraft carriers and small air-capable ships are being pursued for deployment around the turn of the century. To achieve this goal, it is important that technologies critical to this unique class of aircraft be developed. One of the ASTOVL concepts, the vectored thrust, has as its critical technology item, the potential of hot gas ingestion (which occurs during vertical flight operation while in ground effect) as a key development issue. Recognizing this need, NASA Lewis Powered Lift Section and McAir have defined a cooperative program for testing in the Lewis 9 x 15 foot LSWT. This program is described in detail.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Ames Research Center Proceedings of the 1985 NASA Ames Research Center's Ground-Effects Workshop; p 341-361
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  • 79
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    Knowledge based jet engine diagnostics (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A fielded expert system automates equipment fault isolation and recommends corrective maintenance action for Air Force jet engines. The knowledge based diagnostics tool was developed as an expert system interface to the Comprehensive Engine Management System, Increment IV (CEMS IV), the standard Air Force base level maintenance decision support system. XMAM (trademark), the Expert Maintenance Tool, automates procedures for troubleshooting equipment faults, provides a facility for interactive user training, and fits within a diagnostics information feedback loop to improve the troubleshooting and equipment maintenance processes. The application of expert diagnostics to the Air Force A-10A aircraft TF-34 engine equipped with the Turbine Engine Monitoring System (TEMS) is presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lyndon B. Johnson Space Center, Houston, Texas, First Annual Workshop on Space Operations Automation and Robotics (SOAR 87); p 25-30
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  • 80
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    Impact and promise of NASA aeropropulsion technology (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The aeropropulsion industry in the United States has established an enviable record of leading the world in aeropropulsion for commercial and military aircraft. The NASA aeropropulsion propulsion program (primarily conducted through the Lewis Research Center) has significantly contributed to that success through research and technology advances and technology demonstrations such as the Refan, Engine Component Improvement, and the Energy Efficient Engine Programs. Some past NASA contributions to engines in current aircraft are reviewed, and technologies emerging from current research programs for the aircraft of the 1990's are described. Finally, current program thrusts toward improving propulsion systems in the 2000's for subsonic commercial aircraft and higher speed aircraft such as the High-Speed Civil Transport and the National Aerospace Plane (NASP) are discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion '87. Session 1: Aeropropulsion Materials Research; 30 p
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  • 81
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    Results of NASA/Army transmission research (1988)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Since 1970 the NASA Lewis Research Center and the U.S. Army Aviation Systems Command have shared an interest in advancing the technology for helicopter propulsion systems. In particular, that portion of the program that applies to the drive train and its various mechanical components are outlined. The major goals of the program were (and continue to be) to increase the life, reliability, and maintainability, reduce the weight, noise, and vibration, and maintain the relatively high mechanical efficiency of the gear train. Major historical milestones are reviewed, significant advances in technology for bearings, gears, and transmissions are discussed, and the outlook for the future is presented. The reference list is comprehensive.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA, Washington, NASA(Army Rotorcraft Technology. Volume 2: Materials and Structures, Propulsion and Drive Systems, Flight Dynamics and Control, and Acoustics; p 769-801
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  • 82
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    The convertible engine: A dual-mode propulsion system (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A variable inlet guide vane (VIGV) convertible engine that could be used to power future high-speed rotorcraft was tested on an outdoor stand. The engine ran stably and smoothly in the turbofan, turboshaft, and dual (combined fan and shaft) power modes. In the turbofan mode with the VIGV open, fuel consumption was comparable to that of a conventional turbofan engine. In the turboshaft mode with the VIGV closed, fuel consumption was higher than that of present turboshaft engines because power was wasted in churning fan-tip air flow. In dynamic performance tests with a specially built digital engine control and using a waterbrake dynamometer for shaft load, the engine responded effectively to large steps in thrust command and shaft torque. Previous mission analyses of a conceptual X-wing rotorcraft capable of 400-knot cruise speed were revised to account for more fan-tip churning power loss that was originally estimated. The calculations confirm that using convertible engines rather than separate life and cruise engines would result in a smaller, lighter craft with lower fuel use and direct operating cost.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA, Washington, NASA(Army Rotorcraft Technology. Volume 2: Materials and Structures, Propulsion and Drive Systems, Flight Dynamics and Control, and Acoustics; p 737-768
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  • 83
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    Small gas turbine engine technology (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Performance of small gas turbine engines in the 250 to 1,000 horsepower size range is significantly lower than that of large engines. Engines of this size are typically used in rotorcraft, commutercraft, general aviation, and cruise missile applications. Principal reasons for the lower efficiencies of a smaller engine are well known: component efficients are lower by as much as 8 to 10 percentage points because of size effects. Small engines are designed for lower cycle pressures and temperatures because of smaller blading and cooling limitations. The highly developed analytical and manufacturing techniques evolved for large engines are not directly transferrable to small engines. Thus, it was recognized that a focused effort addressing technologies for small engies was needed and could significantly impact their performance. Recently, in-house and contract studies were undertaken at the NASA Lewis Research Center to identify advanced engine cycle and component requirements for substantial performance improvement of small gas turbines for projected year 2000 applications. The results of both in-house research and contract studies are presented. In summary, projected fuel savings of 22 to 42 percent could be obtained. Accompanying direct operating cost reductions of 11 to 17 percent, depending on fuel cost, were also estimated. High payoff technologies are identified for all engine applications, and recent results of experimental research to evolve the high payoff technologies are described.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA, Washington, NASA(Army Rotorcraft Technology. Volume 2: Materials and Structures, Propulsion and Drive Systems, Flight Dynamics and Control, and Acoustics; p 698-736
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  • 84
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    Technology developments for a compound cycle engine (1988)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The Compound Cycle Engine (CCE) is a highly turbocharged, power compounded power plant which combines the light weight pressure rise capability of a gas turbine with the high efficiency of a diesel. When optimized for a rotorcraft, the CCE will reduce fuel burned for a typical 2 hour (plus 30 min reserve) mission by 30 to 40 percent when compared to a conventional advanced technology gas turbine. The CCE can provide a 50 percent increase in range-payload product on this mission. Results of recent activities in a program to establish the technology base for a CCE are presented. The objective of this program is to research and develop those critical technologies which are necessary for the demonstration of a multicylinder diesel core in the early 1990s. A major accomplishment was the initial screening and identification of a lubricant which has potential for meeting the material wear rate limits of the application. An in-situ wear measurement system also was developed to provide accurate, readily obtainable, real time measurements of ring and liner wear. Wear data, from early single cylinder engine tests, are presented to show correlation of the in-situ measurements and the system's utility in determining parametric wear trends. A plan to demonstrate a compound cycle engine by the mid 1990s is included.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA, Washington, NASA(Army Rotorcraft Technology. Volume 2: Materials and Structures, Propulsion and Drive Systems, Flight Dynamics and Control, and Acoustics; p 683-697
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  • 85
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    Hypersonic propulsion research (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The NASA Langley Research Center has conducted hypersonic propulsion research since the 1960s. A variety of inlet concepts were explored and characterized. The emphasis of the inlet program was the development of the short (light weight), fixed geometry, side-wall-compression inlets that operate efficiently over a wide Mach number range. As hypersonic combustion tunnels were developed, programs to study the parameters controlling fuel mixing and combustion with single and multiple strut models were conducted using direct connect test techniques. These various tests supported the design of subscale engine test hardware that integrated inlet and combustor technology and allowed the study of the effect of heat release on thrust and combustor/inlet interaction. A number of subscale engine tests have demonstrated predicted performance levels at Mach 4 and 7 simulated flight conditions.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center, Aeropropulsion '87. Session 6: High-Speed Propulsion Technology; 20 p
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  • 86
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    Supersonic throughflow fans for high-speed aircraft (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Increased need for more efficient long-range supersonic flight has revived interest in the supersonic throughflow fan as a possible component for advanced high-speed propulsion systems. A fan that can operate with supersonic inlet axial Mach numbers would reduce the inlet losses incurred in diffusing the flow from supersonic Mach numbers to a subsonic one at the fan face. In addition, the size and weight of an all-supersonic inlet will be substantially lower than those of a conventional inlet. However, the data base for components of this type is practically nonexistent. Therefore, in order to furnish the required information for assessing the potential for this type of fan, the NASA Lewis Research Center has begun a program to design, analyze, build, and test a fan stage that is capable of operating with supersonic axial velocities from inlet to exit. The objectives are to demonstrate the feasibility and potential of supersonic throughflow fans, to gain a fundamental understanding of the flow physics associated with such systems, and to develop an experimental data base for design and analysis code validation. A brief overview of past supersonic throughflow fan activities are provided; the technology needs discussed; the design of a supersonic throughflow fan stage, a facility inlet, and a downstream diffuser described; and the results from the analysis codes used in executing the design are presented. Also presented is an engine concept intended to permit establishing supersonic throughflow within the fan on the runway and maintaining the supersonic throughflow condition within the fan throughout the flight envelope.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion '87. Session 6: High-Speed Propulsion Technology; 26 p
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  • 87
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    Propulsion challenges and opportunities for high-speed transport aircraft (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: For several years there was a growing interest in the subject of efficient sustained supersonic cruise technology applied to a high-speed transport aircraft. The major challenges confronting the propulsion community for supersonic transport (SST) applications are identified. Both past progress and future opportunities are discussed in relation to perceived technology shortfalls for an economically successful SST that satisfies environmental constraints. A very large improvement in propulsion system efficiency is needed both at supersonic and subsonic cruise conditions. Toward that end, several advanced engine concepts are being considered that, together with advanced discipline and component technologies, promise at least 40 percent better efficiency that the Concorde engine. The quest for higher productivity through higher speed is also thwarted by the lack of a conventional, low-priced fuel that is thermally stable at the higher temperatures associated with faster flight. Airport noise remains a tough challenge because previously researched concepts fall short of achieving FAR 36 Stage 3 noise levels. Innovative solutions may be necessary to reach acceptably low noise. While the technical challenges are indeed formidable, it is reasonable to assume that the current shortfalls in fuel economy and noise can be overcome through an aggressive propulsion research program.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion '87. Session 6: High-Speed Propulsion Technology; 19 p
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  • 88
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    Supersonic STOVL propulsion technology program: An overview (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Planning activities are continuing between NASA, DOD, and two foreign governments to develop the technology and to demonstrate the design capability for advanced, supersonic, short-takeoff and vertical-landing (STOVL) aircraft by the mid-1990s. As a result, a Memorandum of Understanding (MOU) was established by the United Kingdom to jointly pursue the required technology; and an MOU with Canada is expected to be signed shortly. The NASA Lewis Research Center will play a lead role in the development of the required propulsion technologies which were identified as being critical to achieve viable STOVL aircraft. These planning activities have already resulted in initial research programs focused on technologies common to two or more of the proposed propulsion system concepts. An overview of the Lewis Research Center's role in the overall program plan and recent results in the development of the required propulsion technologies is presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion '87. Session 6: High-Speed Propulsion Technology; 23 p
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  • 89
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    Advanced propeller research (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Resent results of aerodynamic and acoustic research on both single and counter-rotation propellers are reviewed. Data and analytical results are presented for three propellers: SR-7A, the single rotation design used in the NASA Propfan Test Assessment (PTA); and F7-A7, the 8+8 counterrotating design used in the proof-of-concept Unducted Fan (UDF) engine. In addition to propeller efficiencies, cruise and takeoff noise, and blade pressure data, off-design phenomena involving formation of leading edge vortices are described. Aerodynamic and acoustic computational results derived from three-dimensional Euler and acoustic radiation codes are presented. Research on unsteady flows, which are particularly important for understanding counterrotation interaction noise, unsteady loading effects on acoustics, and flutter or forced response is described. The first results of three-dimensional unsteady Euler solutions are illustrated for a single rotation propeller at an angle of attack and for a counterrotation propeller. Basic experimental and theoretical results from studies of the unsteady aerodynamics of oscillating cascades are outlined. Finally, advanced concepts involving swirl recovery vanes and ultra bypass ducted propellers are discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion '87. Session 5: Subsonic Propulsion Technology; 30 p
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  • 90
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    Overview of NASA PTA propfan flight test program (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: During the last several years high-speed propellers have made the transition from a wind tunnel curiosity to a very likely near-term, fuel-efficient propulsion system that could revolutionize the subsonic commercial air transport industry. A key ingredient in this remarkable progress is the advanced turboprop industry. Working together, NASA and industry have developed and flight tested two propeller propulsion systems to provide answers to key technical questions and concerns. An industry team is currently developing a third propeller propulsion system for flight testing late this year. The progress of one of the NASA-industry flight test programs, called the Propfan Test Assessment (PTA) Program is reported. In PTA, a 9 foot diameter propfan was installed on the left wing of a Gulfstream GII executive jet and is undergoing extensive flight testing at Dobbins Air Force Base to evaluate propfan structural integrity, near and far field noise, and cabin interior noise characteristics. This research testing includes variations in propeller tip speed and power loading, nacelle tilt angle, and aircraft Mach number and altitude. As a result, extensive parametric data will be obtained to verify and improve computer codes for predicting propeller structural aeroelastic, aerodynamic, and acoustic characteristics. Over 600 measurements are being recorded for each of approximately 600 flight test conditions.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion '87. Session 5: Subsonic Propulsion Technology; 26 p
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  • 91
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    Aircraft engine hot section technology: An overview of the HOST Project (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: NASA sponsored the Turbine Engine Hot Section Technology (HOST) Project to address the need for improved durability in advanced aircraft engine combustors and turbines. Analytical and experimental activities aimed at more accurate prediction of the aerothermal environment, the thermomechanical loads, the material behavior and structural responses to loads, and life predictions for cyclic high-temperature operation were underway for the last 7 years. The project has involved representatives from six engineering disciplines who are spread across three work sectors (industry, academia, and NASA). The HOST Project not only initiated and sponsored 70 major activities, but was also the keystone in joining the multiple disciplines and work sectors to focus on critical research needs. A broad overview of the project is given along with initial indications of the project's impact.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion '87. Session 5: Subsonic Propulsion Technology; 10 p
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  • 92
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    Directions in propulsion control (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The research needs in the area of propulsion control as driven by trends in advanced aircraft are considered. Ongoing propulsion control research at NASA Lewis is discussed. Special emphasis is made on research to improve control system reliability through the use of analytical redundancy to accommodate failed control sensors. In conclusion, a discussion of new research thrusts in the area of supersonic STOVL integrated control and intelligent system control is presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion '87. Session 4: Instrumentation and Controls Research; 15 p
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  • 93
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    Small engine technology programs (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Small engine technology programs being conducted at the NASA Lewis Research Center are described. Small gas turbine research is aimed at general aviation, commutercraft, rotorcraft, and cruise missile applications. The Rotary Engine Program is aimed at supplying fuel flexible, fuel efficient technology to the general aviation industry, but also has applications to other missions. There is a strong element of synergism between the various programs in several respects. All of the programs are aimed towards highly efficient engine cycles, very efficient components, and the use of high temperature structural ceramics. This research tends to be generic in nature and has broad applications. The Heavy Duty Diesel Transport (HDTT), rotary technology, and the compound cycle programs are all examining approached to minimum heat rejection, or adiabatic systems employing advanced materials. The Automotive Gas Turbine (AGT) program is also directed towards ceramics application to gas turbine hot section components. Turbomachinery advances in the gas turbines will benefit advanced turbochargers and turbocompounders for the intermittent combustion systems, and the fundamental understandings and analytical codes developed in the research and technology programs will be directly applicable to the system projects.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion '87. Session 5: Subsonic Propulsion Technology; 35 p
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  • 94
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    Turbomachinery (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The discipline research in turbomachinery, which is directed toward building the tools needed to understand such a complex flow phenomenon, is based on the fact that flow in turbomachinery is fundamentally unsteady or time dependent. Success in building a reliable inventory of analytic and experimental tools will depend on how the time and time-averages are treated, as well as on who the space and space-averages are treated. The raw tools at disposal (both experimentally and computational) are truly powerful and their numbers are growing at a staggering pace. As a result of this power, a case can be made that a situation exists where information is outstripping understanding. The challenge is to develop a set of computational and experimental tools which genuinely increase understanding of the fluid flow and heat transfer in a turbomachine. Viewgraphs outline a philosophy based on working on a stairstep hierarchy of mathematical and experimental complexity to build a system of tools, which enable one to aggressively design the turbomachinery of the next century. Examples of the types of computational and experimental tools under current development at Lewis, with progress to date, are examined. The examples include work in both the time-resolved and time-averaged domains. Finally, an attempt is made to identify the proper place for Lewis in this continuum of research.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion '87. Session 3: Internal Fluid Mechanics Research; 23 p
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  • 95
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    Integrated analysis and applications (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A select overview is provided of ongoing research focusing on the development and verification of integrated structural analysis and optimal design capabilities for advanced aerospace propulsion and power systems. Subjects discussed include the following: (1) Composites - analytical models (composite mechanics), integrated computational methods, and characterization of composite structural response and durability for resin-, metal-, and ceramic-matrix systems; (2) Advanced inelastic analysis - algorithm/numerical methods for more accurate and efficient analysis; (3) Constitutive modeling - theoretical formulation and characterization of thermoviscoplastic material behavior; (4) Computational simulation - engine structures from components to assembly, and up to an entire engine system subjected to simulated test-stand and mission load histories; (5) Probabilistic structural analysis - quantification of the effects of uncertainty in geometry, material, loads, and boundary conditions on structural response for true reliability assessment; and (6) Interdisciplinary optimization - incorporation of mathematical optimization and multidisciplinary analyses to provide streamlined, autonomous optimal design systems.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion '87. Session 2: Aeropropulsion Structures Research; 12 p
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  • 96
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    Life prediction technologies for aeronautical propulsion systems (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Fatigue and fracture problems continue to occur in aeronautical gas turbine engines. Components whose useful life is limited by these failure modes include turbine hot-section blades, vanes and disks. Safety considerations dictate that catastrophic failures be avoided, while economic considerations dictate that noncatastrophic failures occur as infrequently as possible. The design decision is therefore in making the tradeoff between engine performance and durability. The NASA Lewis Research Center has contributed to the aeropropulsion industry in the areas of life prediction technology for 30 years, developing creep and fatigue life prediction methodologies for hot-section materials. Emphasis is placed on the development of methods capable of handling both thermal and mechanical fatigue under severe environments. Recent accomplishments include the development of more accurate creep-fatigue life prediction methods such as the total strain version of Lewis' Strainrange Partitioning (SRP) and the HOST-developed Cyclic Damage Accumulation (CDA) model. Other examples include the Double Damage Curve Approach (DDCA), which provides greatly improved accuracy for cumulative fatigue design rules.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion '87. Session 2: Aeropropulsion Structures Research; 12 p
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  • 97
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    Aeropropulsion structures (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The structural engineer is faced with unique problems when dealing with aeropropulsion systems. He is faced with extremes in operating temperatures, rotational effects, and behaviors of advanced material systems which combine into complexities that require advances in many scientific disciplines involved in structural analysis and design procedures. This presentation provides an overview of the complexities of aeropropulsion structures and the theoretical, computational, and experimental research conducted to achieve the needed advances.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion '87. Session 2: Aeropropulsion Structures Research; 10 p
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  • 98
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    Determining structural performance (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: An overview is given of the methods and concepts developed to enhance and predict structural dynamic characteristics of advanced aeropropulsion systems. Aeroelasticity, Vibration Control, Dynamic Systems, and Computational Structural Methods are four disciplines that make up the research program at NASA/Lewis Research Center. The Aeroelasticity program develops analytical and experimental methods to minimize flutter and forced vibration of aerospace propulsion systems. Both frequency domain and time domain methods have been developed for applications on the turbofan, turbopump, and advanced turboprop. To improve life and performance, the Vibration Control program conceives, analyzes, develops, and demonstrates new methods to control vibrations in aerospace systems. Active and passive vibration control is accomplished with electromagnetic dampers, magnetic bearings, and piezoelectric crystals to control rotor vibrations. The Dynamic Systems program analyzes and verifies the dynamics of interacting systems, as well as develops concepts and methods for high-temperature dynamic seals. The Computational Structural Methods program uses computer science to improve solutions of structural problems.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeropropulsion '87. Session 2: Aeropropulsion Structures Research; 14 p
    Format: application/pdf
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  • 99
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    The scaling of model test results to predict intake hot gas reingestion for STOVL aircraft with augmented vectored thrust engines (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The difficulties of modeling the complex recirculating flow fields produced by multiple jet STOVL aircraft close to the ground have led to extensive use of experimental model tests to predict intake Hot Gas Reingestion (HGR). Model test results reliability is dependent on a satisfactory set of scaling rules which must be validated by fully comparable full scale tests. Scaling rules devised in the U.K. in the mid 60's gave good model/full scale agreement for the BAe P1127 aircraft. Until recently no opportunity has occurred to check the applicability of the rules to the high energy exhaust of current ASTOVL aircraft projects. Such an opportunity has arisen following tests on a Tethered Harrier. Comparison of this full scale data and results from tests on a model configuration approximating to the full scale aircraft geometry has shown discrepancies between HGR levels. These discrepancies although probably due to geometry and other model/scale differences indicate some reexamination of the scaling rules is needed. Therefore the scaling rules are reviewed, further scaling studies planned are described and potential areas for further work are suggested.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Ames Research Center Proceedings of the 1985 NASA Ames Research Center's Ground-Effects Workshop; p 309-339
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  • 100
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    Experimental investigation of piloted flameholders (1986)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Four configurations of piloted flameholders were tested. The range of flame stabilization, flame propagation, pressure oscillation during ignition, and pressure drop of the configurations were determined. Some tests showed a very strong effect of inlet flow velocity profile and flameholder geometry on flame stabilization. These tests led to the following conclusions. (1) The use of a piloted flameholder in the turbofan augmentor may minimize the peak pressure rise during ignition. At the present experimental conditions, delta P/P asterisk over 2 is less than 10 percent; therefore, the use of a piloted flameholder is a good method to realize soft ignition. (2) The geometry of the piloted flameholder and the amount of fuel injected into the flameholder have a strong effect on the pressure oscillation during ignition of the fuel-air mixture in the secondary zone. (3) Compared with the V-gutter flameholder with holes in its wall, the V-gutter flameholder without holes not only has advantages such as simple structure and good rigidity but offers a wide combustion stability limit and a high capability of igniting the fuel-air mixture of the secondary zone.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA- Lewis Research Center NASA-Chinese Aeronautical Establishment (CAE) Symposium; p 191-205
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