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Results for “PERFORMANCE, ENGINEERING”

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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1951

Generalization of turbojet and turbine-propeller engine performance in windmilling condition

Windmilling characteristics of several turbojet and turbine-propeller engines were investigated individually over a wide range of flight conditions in the NACA Lewis altitude wind tunnel. A study was made of all these data and windmilling performance of gas turbine engines was generalized. Although internal-drag, air-flow, and total-pressure-drop parameters were generalized to a single curve for both the axial-flow type engines and another for the centrifugal-flow engine. The engine speed, component pressure changes, and windmilling-propeller drag were generalized to single curves for the two turbine-propeller-type engines investigated. By the use of these curves the windmilling performance can be estimated for axial-flow type gas turbine engines similar to the types investigated over a wide range of flight conditions.

Wallner, Ewis E↗
NASA NTRSDate not supplied

Computational Assessment of the Impact of Wave Count on Rotating Detonation Engine Performance

The impact of the number of azimuthally propagating waves on the performance of a Rotating Detonation Engine (RDE) is investigated using a simplified two-dimensional computational fluid dynamic simulation. The basic RDE configuration examined has no exit throat. The inlet is assumed lossless and does not allow backflow. The adiabatic, inviscid, and premixed simulation utilizes a particularly simple finite rate reaction mechanism that allows user control over the relative amounts of deflagration and detonation that occur, the presence and extent of a reaction delay associated with fuel and oxidizer mixing, and the number of waves present in the domain. The simplifications and idealizations decouple the effect of wave count from other potential loss mechanisms. Performance is measured using exhaust flow total pressure gain relative to the inlet total pressure. One, two, and three wave solutions are computed under identical boundary conditions and grid resolution. For simulations with no mixing delay and minimal deflagration, the number of waves present has negligible impact on performance. With a mixing delay, performance decreases with increasing wave number. With increased deflagration, performance increases with increasing wave number. With both effects simulated it is found that the two wave solution performs better than either the one or three wave solutions. The causes of these trends are explored. They imply that for practical, RDE’s, the number of waves that are present can impact performance.

Detonation↗
NASA NTRSDate not supplied

Computational Assessment of the Impact of Wave Count on Rotating Detonation Engine Performance

The impact of the number of azimuthally propagating waves on the performance of a Rotating Detonation Engine (RDE) is investigated using a simplified two-dimensional computational fluid dynamic simulation. The basic RDE configuration examined has no exit throat. The inlet is assumed lossless and does not allow backflow. The adiabatic, inviscid, and premixed simulation utilizes a particularly simple finite rate reaction mechanism that allows user control over the relative amounts of deflagration and detonation that occur, the presence and extent of a reaction delay associated with fuel and oxidizer mixing, and the number of waves present in the domain. The simplifications and idealizations decouple the effect of wave count from other potential loss mechanisms. Performance is measured using exhaust flow total pressure gain relative to the inlet total pressure. One, two, and three wave solutions are computed under identical boundary conditions and grid resolution. For simulations with no mixing delay and minimal deflagration, the number of waves present has negligible impact on performance. With a mixing delay, performance decreases with increasing wave number. With increased deflagration, performance increases with increasing wave number. With both effects simulated it is found that the two wave solution performs better than either the one or three wave solutions. The causes of these trends are explored. They imply that for practical, RDE’s, the number of waves that are present can impact performance.

Detonation↗
NASA NTRS2016

Practical Techniques for Modeling Gas Turbine Engine Performance

The cost and risk associated with the design and operation of gas turbine engine systems has led to an increasing dependence on mathematical models. In this paper, the fundamentals of engine simulation will be reviewed, an example performance analysis will be performed, and relationships useful for engine control system development will be highlighted. The focus will be on thermodynamic modeling utilizing techniques common in industry, such as: the Brayton cycle, component performance maps, map scaling, and design point criteria generation. In general, these topics will be viewed from the standpoint of an example turbojet engine model; however, demonstrated concepts may be adapted to other gas turbine systems, such as gas generators, marine engines, or high bypass aircraft engines. The purpose of this paper is to provide an example of gas turbine model generation and system performance analysis for educational uses, such as curriculum creation or student reference.

aerothermodynamics↗
NASA NTRS2016

Practical Techniques for Modeling Gas Turbine Engine Performance

The cost and risk associated with the design and operation of gas turbine engine systems has led to an increasing dependence on mathematical models. In this paper, the fundamentals of engine simulation will be reviewed, an example performance analysis will be performed, and relationships useful for engine control system development will be highlighted. The focus will be on thermodynamic modeling utilizing techniques common in industry, such as: the Brayton cycle, component performance maps, map scaling, and design point criteria generation. In general, these topics will be viewed from the standpoint of an example turbojet engine model; however, demonstrated concepts may be adapted to other gas turbine systems, such as gas generators, marine engines, or high bypass aircraft engines. The purpose of this paper is to provide an example of gas turbine model generation and system performance analysis for educational uses, such as curriculum creation or student reference.

aerothermodynamics↗
NASA NTRS1981

Space Shuttle main engine performance assessment - Columbia's first flight

Design features and performance of the Shuttle main engines first flight are presented. Each of the three engines produces 470,000 lb of thrust, operates at 3,012 psia, and has a 77.5 to 1 nozzle expansion ratio. The engines are designed for a 7.5 hr operational life, and will be tested at 109% capacity in future Shuttle flights. The developmental program is outlined, and includes 127,000 sec of operational testing on 19 engines. Engine operations and components are described, noting 100% burning of the hydrogen and oxidizer, high pressure fuel turbopumps, the controller assembly, etc.; details of solutions to fatigue failures and subsequent certification are provided. The nine minute first flight firing revealed a radiant heating of a control sensor transducer, which was shielded for succeeding flights. Alternatives are given for thrust augmentation, for which each 1% yields an additional 800 lb payload increase capability, and can be implemented by 1987.

Thompson, J. R., Jr.↗
NASA NTRS1956

Analysis of ram-jet engine performance including effects of component changes

Calculated design-point performance of ram-jet engines using JP-4 fuel is presented for a wide range of engine total-temperature ratios and combustion-chamber-inlet Mach numbers for flight numbers from 1.5 to 4.0. The results include engine thrust, drag, fuel consumption, and area ratios. Data are also presented to illustrate the sensitivity of the results to variations in the assumed component parameters. A brief comparison is included between fixed-and variable-geometry engines.

Weber, Richard J↗
NASA NTRS2002

Airbreathing Pulse Detonation Engine Performance

This paper presents performance results for pulse detonation engines (PDE) taking into account the effects of dissociation and recombination. The amount of sensible heat recovered through recombination in the PDE chamber and exhaust process was found to be significant. These results have an impact on the specific thrust, impulse and fuel consumption of the PDE.

Povinelli, Louis A.↗
NASA NTRS2002

Airbreathing Pulse Detonation Engine Performance

This paper presents performance results for pulse detonation engines taking into account the effects of dissociation and recombination. The amount of sensible heat recovered through recombination in the PDE chamber and exhaust process was found to be significant. These results have an impact on the specific thrust, impulse and fuel consumption of the PDE.

Povinelli, Louis A.↗
NASA NTRS1980

AiResearch QCGAT engine performance and emissions tests

Results of aerodynamic performance and emission tests, conducted on a specially designed QCGAT engine in the 17,793-N (4,000 lb) thrust class, are presented. Performance of the AiResearch QCGAT engine was excellent throughout all testing. No serious mechanical malfunctions were encountered, and no significant test time was lost due to engine-related problems. Emissions were drastically reduced over similar engines, and the engine exhibited good smoke performance.

Norgren, W. M.↗
NASA NTRS1998

Engineering Performance

Under Goddard Space Flight Center and Jet Propulsion Laboratory SBIR (Small Business Innovative Research) contracts, AST Engineering Services, Inc. developed a system engineering computer software tool to model how certain applications will affect a proposed system's performance. Quantitative System Engineering (QASE) evaluates system timing, capacity and availability. The system is used to predict performance of proposed real-time, aerospace systems, embedded systems, and/or scientific systems, as well as in support of NASA's EDOS (Earth Observing System (EOS) Data and Operations System) initiative.

Source record↗
NASA NTRS1975

DC-9 Flight Demonstration Program with Refanned JT8D Engines: Performance and Analysis - Volume 3

The JT8D-109 engine has a sea level static, standard day bare engine takeoff thrust of 73,840 N. At sea level standard day conditions the additional thrust of the JT8D-109 results in 2,040 kg additional takeoff gross weight capability for a given field length. Range loss of the DC-9 Refan airplane for long range cruise was determined. The Refan airplane demonstrated stall, static longitudinal stability, longitudinal control, longitudinal trim, minimum control speeds, and directional control characteristics similar to the DC-9-30 production airplane and complied with airworthiness requirements. Cruise, climb, and thrust reverser performance were evaluated. Structural and dynamic ground test, flight test and analytical results substantiate Refan Program requirements that the nacelle, thrust reverser hardware, and the airplane structural modifications are flightworthy and certifiable and that the airplane meets flutter speed margins. Estimated unit cost of a DC-9 Refan retrofit program is 1.338 million in mid-1975 dollars with about an equal split in cost between airframe and engine.

Source record↗
NASA NTRS1979

CF6 jet engine performance improvement program. Short core exhaust nozzle performance improvement concept

The short core exhaust nozzle was evaluated in CF6-50 engine ground tests including performance, acoustic, and endurance tests. The test results verified the performance predictions from scale model tests. The short core exhaust nozzle provides an internal cruise sfc reduction of 0.9 percent without an increase in engine noise. The nozzle hardware successfully completed 1000 flight cycles of endurance testing without any signs of distress.

Fasching, W. A.↗
NASA NTRS1992

Thrust stand evaluation of engine performance improvement algorithms in an F-15 airplane

An investigation is underway to determine the benefits of a new propulsion system optimization algorithm in an F-15 airplane. The performance seeking control (PSC) algorithm optimizes the quasi-steady-state performance of an F100 derivative turbofan engine for several modes of operation. The PSC algorithm uses an onboard software engine model that calculates thrust, stall margin, and other unmeasured variables for use in the optimization. As part of the PSC test program, the F-15 aircraft was operated on a horizontal thrust stand. Thrust was measured with highly accurate load cells. The measured thrust was compared to onboard model estimates and to results from posttest performance programs. Thrust changes using the various PSC modes were recorded. Those results were compared to benefits using the less complex highly integrated digital electronic control (HIDEC) algorithm. The PSC maximum thrust mode increased intermediate power thrust by 10 percent. The PSC engine model did very well at estimating measured thrust and closely followed the transients during optimization. Quantitative results from the evaluation of the algorithms and performance calculation models are included with emphasis on measured thrust results. The report presents a description of the PSC system and a discussion of factors affecting the accuracy of the thrust stand load measurements.

Conners, Timothy R.↗
NASA NTRS1983

Computer program for Stirling engine performance calculations

The thermodynamic characteristics of the Stirling engine were analyzed and modeled on a computer to support its development as a possible alternative to the automobile spark ignition engine. The computer model is documented. The documentation includes a user's manual, symbols list, a test case, comparison of model predictions with test results, and a description of the analytical equations used in the model.

Tew, R. C., Jr.↗
NASA NTRS1978

JT9D jet engine performance deterioration

The analytical techniques utilized to examine the effects of flight loads and engine operating conditions on performance deterioration are presented. The role of gyroscopic, gravitational, and aerodynamic loads are shown along with the effect of variations in engine build clearances. These analytical results are compared to engine test data along with the correlation between analytically predicted and measured clearances and rub patterns. Conclusions are drawn and important issues are discussed.

Jay, A.↗