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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,657 records · Page 92

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NASA NTRS1974

Engineering education and a lifetime of learning

The result of an eleven-week study by the National Aeronautics and Space Administration (NASA) and the American Society of Engineering Education is presented. The study was the ninth of a series of programs. The purposes of the programs were: (1) to introduce engineering school faculty members to system design and to a particular approach to teaching system design, (2) to introduce engineering faculty to NASA and to a specific NASA center, and (3) to produce a study of use to NASA and to the participants. The story was concerned with engineering education in the U.S., and concentrated upon undergraduate education and teaching, although this bias was not meant to imply that research and graduate study are less important to engineering education.

Eisley, J.↗

NASA NTRS1975

Application of real-time engine simulations to the development of propulsion system controls

The development of digital controls for turbojet and turbofan engines is presented by the use of real-time computer simulations of the engines. The engine simulation provides a test-bed for evaluating new control laws and for checking and debugging control software and hardware prior to engine testing. The development and use of real-time, hybrid computer simulations of the Pratt and Whitney TF30-P-3 and F100-PW-100 augmented turbofans are described in support of a number of controls research programs at the Lewis Research Center. The role of engine simulations in solving the propulsion systems integration problem is also discussed.

Szuch, J. R.↗

NASA NTRS1975

Experience with integrally-cast compressor and turbine components for a small, low-cost, expendable-type turbojet engine

Experiences with integrally-cast compressor and turbine components during fabrication and testing of four engine assemblies of a small (29 cm (11 1/2 in.) maximum diameter) experimental turbojet engine design for an expendable application are discussed. Various operations such as metal removal, welding, and re-shaping of these components were performed in preparation of full-scale engine tests. Engines with these components were operated for a total of 157 hours at engine speeds as high as 38,000 rpm and at turbine inlet temperatures as high as 1256 K (1800 F).

Dengler, R. P.↗

NASA NTRS1975

Orbital maneuvering engine feed system coupled stability investigation

A digital computer model used to analyze and predict engine feed system coupled instabilities over a frequency range of 10 to 1000 Hz was developed and verified. The analytical approach to modeling the feed system hydrodynamics, combustion dynamics, chamber dynamics, and overall engineering model structure is described and the governing equations in each of the technical areas are presented. This is followed by a description of the generalized computer model, including formulation of the discrete subprograms and their integration into an overall engineering model structure. The operation and capabilities of the engineering model were verified by comparing the model's theoretical predictions with experimental data from an OMS-type engine with a known feed system/engine chugging history.

Kahn, D. R.↗

NASA NTRS1975

Wind tunnel investigation of a large-scale upper surface blown-flap model having four engines

Investigations were conducted in the Ames 40- by 80-Foot Wind Tunnel to determine the aerodynamic characteristics of a large-scale subsonic jet transport model with an upper surface blown flap system. The model had a 25 deg swept wing of aspect ratio 7.28 and four turbofan engines. The lift of the flap system was augmented by turning the turbofan exhaust over the Coanda surface. Results were obtained for several flap deflections with several wing leading-edge configurations at jet momentum coefficients from 0 to 4.0. Three-component longitudinal data are presented with four engines operating. In addition, longitudinal and lateral data are presented with an engine out. The maximum lift and stall angle of the four engine model were lower than those obtained with a two engine model that was previously investigated. The addition of the outboard nacelles had an adverse effect on these values. Efforts to improve these values were successful. A maximum lift of 8.8 at an angle-of-attack of 27 deg was obtained with a jet thrust coefficient of 2 for the landing flap configuration.

Aoyagi, K.↗

NASA NTRS1975

Application of real-time engine simulations to the development of propulsion system controls

The development of digital controls for turbojet and turbofan engines can be facilitated by the use of real-time computer simulations of the engines. The engine simulation provides a 'test-bed' for evaluating new control laws and for checking and 'debugging' control software and hardware prior to engine testing. This paper describes the development and use of real-time, hybrid computer simulations of the Pratt & Whitney TF30-P-3 and F100-PW-100 augmented turbofans in support of a number of controls research programs at the Lewis Research Center. The role of engine simulations in solving the propulsion systems integration problem is also discussed.

Szuch, J. R.↗

NASA NTRS1975

Linear rocket engines for advanced space transportation systems

The linear rocket engine is shown to be a viable candidate propulsion system for post-Space Shuttle single-stage-to-orbit systems. The linear engine system has been developed and fired demonstrating high performance and long life with firing durations exceeding 500 seconds. The application of the split or dual combustor to the linear engine permits the uses of two different propellant combinations in a single engine system. The split combustor possesses the advantages of the two position extendible bell nozzle in a fixed nozzle configuration. Engine power cycles and applications to typical vehicles are discussed.

Sobin, A. J.↗

NASA NTRS1975

DC-9 flight demonstration program with refanned JT8D engines. Volume 1: Summary

The design, analysis, fabrication, and ground and flight testing of DC-9 airframe/nacelle hardware with prototype JT8D-109 engines are discussed. The installation of the JT8D-109 engine on the DC-9 Refan airplane required new or modified hardware for the pylon, nacelle, and fuselage. The acoustic material used in the nose cowl was bonded aluminum honeycomb sandwich and the exhaust duct acoustic material was Inconel 625 Stresskin. The sea level static, standard day bare engine takeoff thrust, the cruise TSFC and the maximum available cruise thrust for the JT8D-109 engine were compared with those of the JT8D-9 engine. The range capabilities of the DC-9 Refan and the production DC-9 airplane were also compared. The Refan airplane demonstrated flight characteristics similar to the production DC-9-30 and satisfied airworthiness requirements. Flyover noise levels were determined for the DC-9 Refan and the DC-9 C-9A airplane for takeoff and landing conditions. Cost estimates were also made.

Source record↗

NASA NTRS1975

Design and evaluation of a sensor fail-operational control system for a digitally controlled turbofan engine

A self-learning, sensor fail-operational, control system for the TF30-P-3 afterburning turbofan engine was designed and evaluated. The sensor fail-operational control system includes a digital computer program designed to operate in conjunction with the standard TF30-P-3 bill-of-materials control. Four engine measurements and two compressor face measurements are tested. If any engine measurements are found to have failed, they are replaced by values synthesized from computer-stored information. The control system was evaluated by using a realtime, nonlinear, hybrid computer engine simulation at sea level static condition, at a typical cruise condition, and at several extreme flight conditions. Results indicate that the addition of such a system can improve the reliability of an engine digital control system.

Hrach, F. J.↗

NASA NTRS1975

Composite engines for application to a single-stage-to-orbit vehicle

Seven composite engines were designed for application to a reusable single-stage-to-orbit vehicle. The engine designs were variations of the supercharged ejector ramjet engine. The resulting performance, weight, and drawings of each engine form a data base for establishing a potential of this class of composite engine to various missions, including the single-stage-to-orbit application. The impact of advanced technology in the design of the critical fan turbine was established.

Bendot, J. G.↗

NASA NTRS1976

Thrust and wing loading requirements for short haul aircraft constrained by engine noise and field length

Propulsion system and wing loading requirements are determined for a mechanical flap and an externally blown flap aircraft for various engine noise levels and two engine cycles. Both aircraft are sized to operate from a 914m (3000 ft) runway and perform the same mission. For each aircraft concept, propulsion system sizing is demonstrated for two different engine cycles - one having a fan pressure ratio of 1.5 and a bypass ratio of 9, and the other having a fan pressure ratio of 1.25 and a bypass ratio of 17.8. The results presented include the required thrust-to-weight ratio, wing loading, resulting gross weight, and direct operating costs, as functions of the engine noise level, for each combination of engine cycle and aircraft concept.

Bowles, J. V.↗

NASA NTRS1976

Effects of airplane characteristics and takeoff noise and field length constraints on engine cycle selection for a Mach 2.32 cruise application

Sideline noise and takeoff field length were varied for two types of Mach 2.32 cruise airplane to determine their effect on engine cycle selection. One of these airplanes was the NASA/Langley-LTV arrow wing while the other was a Boeing modified delta-plus-tail derived from the earlier 2707-300 concept. Advanced variable cycle engines were considered. A more conventional advanced low bypass turbofan engine was used as a baseline for comparison. Appropriate exhaust nozzle modifications were assumed, where needed, to allow all engines to receive either an inherent co-annular or annular jet noise suppression benefit. All the VCE's out-performed the baseline engine by substantial margins in a design range comparison, regardless of airplane choice or takeoff restrictions. The choice among the three VCE's considered, however, depends on the field length, noise level, and airplane selected.

Whitlow, J. B., Jr.↗

NASA NTRS1976

Stimulation of a turbofan engine for evaluation of multivariable optimal control concepts

The development of control systems for jet engines requires a real-time computer simulation. The simulation provides an effective tool for evaluating control concepts and problem areas prior to actual engine testing. The development and use of a real-time simulation of the Pratt and Whitney F100-PW100 turbofan engine is described. The simulation was used in a multi-variable optimal controls research program using linear quadratic regulator theory. The simulation is used to generate linear engine models at selected operating points and evaluate the control algorithm. To reduce the complexity of the design, it is desirable to reduce the order of the linear model. A technique to reduce the order of the model; is discussed. Selected results between high and low order models are compared. The LQR control algorithms can be programmed on digital computer. This computer will control the engine simulation over the desired flight envelope.

Seldner, K.↗

NASA NTRS1975

Experience with integrally-cast compressor and turbine components for a small, low-cost, expendable-type turbojet engine

A discussion regarding experiences with integrally-cast compressor and turbine components during fabrication and testing of four engine assemblies of a small (29 cm (11-1/2 in.) maximum diameter) experimental turbojet engine design for an expendable application is presented. Various operations such as metal removal, welding, and re-shaping of these components are performed in preparation of full-scale engine tests. Engines with these components have been operated for a total of 157 hours at engine speeds as high as 38,000 rpm and at turbine inlet temperatures as high as 1256 K (1800 F).

Dengler, R. P.↗

NASA NTRS1976

Research requirements for emergency power to permit hover-one-engine-inoperative helicopter operation

The research and technology demonstration requirements to achieve emergency-power capability for a civil helicopter are documented. The goal for emergency power is the ability to hover with one engine inoperative, transition to minimum-power forward flight, and continue to a safe landing where emergency power may or may not be required. The best method to obtain emergency power is to augment the basic engine power by increasing the engine's speed and turbine-inlet temperature, combined with water-alcohol injection at the engine inlet. Other methods, including turbine boost power and flywheel energy, offer potential for obtaining emergency power for minimum time durations. Costs and schedules are estimated for a research and development program to bring emergency power through a hardware-demonstration test. Interaction of engine emergency-power capability with other helicopter systems is examined.

Yost, J. H.↗

NASA NTRS1977

Analysis of liquid-propellant rocket engines designed by F. A. Tsander

The development of the oxygen-gasoline OR-2 engines and the oxygen-alcohol GIRD-10 rocket engine is described. A result of Tsander's rocket research was an engineering method for propellant calculation of oxygen-propellant rocket engines that determined the basic parameters of the engine and the structural elements.

Dushkin, L. S.↗

NASA NTRS1976

Supersonic combustion ramjet /scramjet/ engine development in the United States

This survey of supersonic combustion ramjet (scramjet) engine development in the United States covers development of this unique engine cycle from its inception in the early 1960's through the various programs currently being pursued and, in some instances, describing the future direction of the programs. These include developmental efforts supported by the U.S. Navy, National Aeronautics and Space Administration, and U.S. Air Force. Results of inlet, combustor, and nozzle component tests, free-jet engine tests, analytical techniques developed to analyze and predict component and engine performance, and flight-weight hardware development are presented. These results show that efficient scramjet propulsion is attainable in a variety of flight configurations with a variety of fuels. Since the scramjet is the most efficient engine cycle for hypersonic flight within the atmosphere, it should be given serious consideration in future propulsion schemes

Waltrup, P. J.↗

NASA NTRS1977

Quiet, Clean, Short-Haul Experimental Engines /QCSEE/ - A technology development program

NASA's QCSEE Program (Quiet, Clean, Short-Haul Experimental Engine) performed by the General Electric Company covers a wide range of advanced propulsion technology features applicable to future subsonic engine concepts. These technology features are combined into two engine and nacelle configurations for demonstration of program goals. This paper presents descriptions of two engine/nacelle configurations and shows the flow of technology developed in component programs into the configurations. The under-the-wing (UTW) configuration, featuring major innovative and advanced components, such as a large variable pitch fan and a composite material integrated engine and nacelle structure, has been tested at General Electric's Peebles, Ohio test facility. The key characteristics of the engine as observed from the initial test series are presented.

Willis, W. S.↗