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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Port geometry effects on thrust reverser static performance

An investigation has been conducted to provide some insight into the effect of several geometric parameters on the internal performance of thrust reverser ports for nonaxisymmetric nozzles using a single port test apparatus. This test apparatus simulates thrust reversal (conceptually) which would occur in the convergent section of the forward flight nozzle or in the constant area duct just upstream. The port opening had an aspect ratio of 6.1 (throat width/throat height) and had constant passage area from the geometric throat to the exit. The geometric parameters investigated were port angle, port corner radius, port location, and flow blocker angle. The apparatus had a single port so that thrust (vector) angle could be obtained from force balance measurements. The tests were conducted in the Static Test Stand of the Langley 16-Foot Transonic Tunnel at nozzle pressure ratios from 1.5 to 8.0 using high pressure air for propulsion simulation. Port angles (measured forward from a horizontal reference line) investigated were 75, 90, 120 and 135 deg. Sharp and rounded port corners were investigated for each port angle. Discharge coefficient, thrust ratio, and passage static pressures were measured.

Re, R. J.↗
NASA NTRS1980

Investigation of convergent-divergent nozzles applicable to reduced-power supersonic cruise aircraft

An investigation was conducted of isolated convergent-divergent nozzles to determine the effect of several design parameters on nozzle performance. Tests were conducted using high pressure air for propulsion simulation at Mach numbers from 0.60 to 2.86 at an angle of attack of 0 deg and at nozzle pressure ratios from jet off to 46.0. Three power settings (dry, partial afterburning, and maximum afterburning), three nozzle lengths, and nozzle expansion ratios from 1.22 to 2.24 were investigated. In addition, the effects of nozzle throat radius and a cusp in the external boattail geometry were studied. The results of this study indicate that, for nozzles operating near design conditions, increasing nozzle length increases nozzle thrust-minus-drag performance. Nozzle throat radius and an external boattail cusp had negligible effects on nozzle drag or internal performance.

Berrier, B. L.↗
NASA NTRS1985

Hover test results of a small-scale twin-tilt nacelle model

Characteristics in hover of an 11/36%-scale, powered, twin-tilt nacelle model were measured in the NASA Ames Research Center's 40- by 80-Foot Wind Tunnel. The model was powered by two high-pressure air-driven turbofan propulsion simulators. The position of the sting-mounted model was fixed and a movable ground plane was used to vary ground height and orientation. Hover characteristics were investigated in and out of ground effect for roll angles of -2 deg to +14 deg and pitch angles of -15 deg to +10 deg. Results for the basic configurations are compared with data from hover tests of the full-scale tilt nacelle model. Two methods were investigated to increase vertical vane effectiveness: (1) extending the maximum vane deflection from 20 deg to 70 deg, and (2) adding a third vertical vane. The goal was to increase the roll-control capability to significantly reduce or balance the strong, unfavorable rolling moment created by the loss of one engine. Results indicate that the three-vertical-vane configuration is more effective than two vertical vanes and that extended vane deflections significantly reduce the engine-out roll in hover.

Schmidt, S. B.↗
NASA NTRS1985

Propulsion and airframe aerodynamic interactions of supersonic V/STOL configurations, phase 1

A wind tunnel model of a supersonic V/STOL fighter configuration has been tested to measure the aerodynamic interaction effects which can result from geometrically close-coupled propulsion system/airframe components. The approach was to configure the model to present two different test techniques. One was a coventional test technique composed of two test modes. In the Flow-Through mode, absolute configuration aerodynamics are measured, including inlet/airframe interactions. In the Jet-Effects mode, incremental nozzle/airframe interactions are measured. The other test technique is a propulsion simulator approach, where a subscale, externally powered engine is mounted in the model. This allows proper measurement of inlet/airframe and nozzle/airframe interactions simultaneously.

Mraz, M. R.↗
NASA NTRS1988

A flow-transfer device with nonmetallic diaphragms for propulsion wind tunnel models

The Langley Research Center has developed a new flow-transfer device for powered wind tunnel models in which the traditional metal bellows have been replaced with nonmetallic diaphragms. Two complete flow transfer assemblies have been fabricated and installed within a twin-jet propulsion simulation system. Calibrations of the force balance have been performed over a range of nozzle mass flow rates up to 15 lbs/sec in order to validate the nonmetallic diaphragm design concept. Results from these calibrations are compared to those obtained with flow-transfer devices utilizing metal bellows.

Capone, Francis J.↗
NASA NTRS1988

Scale model acoustic testing of counterrotating fans

The UDF contrarotating propfan has been subjected to scale model wind tunnel testing to ascertain both general performance and acoustic characteristics data bases. Model Propulsion Simulator test rigs able to mount contrarotating fan blades of up to 24.5-inch diameter were used, and one of these was installed in a large anechoic test chamber for acoustic measurement of conditions simulating representative takeoffs, power cutbacks, and landing approaches. Attention is presently given to the data acquisition/reduction systems, the scaling criteria used to obtain engine size acoustic data, and comparisons with demonstrator aircraft in-flight acoustic test results.

Janardan, B. A.↗
NASA NTRS1990

Experimental performance and acoustic investigation of modern, counterrotating blade concepts

The aerodynamic, acoustic, and aeromechanical performance of counterrotating blade concepts were evaluated both theoretically and experimentally. Analytical methods development and design are addressed. Utilizing the analytical methods which evolved during the conduct of this work, aerodynamic and aeroacoustic predictions were developed, which were compared to NASA and GE wind tunnel test results. The detailed mechanical design and fabrication of five different composite shell/titanium spar counterrotating blade set configurations are presented. Design philosophy, analyses methods, and material geometry are addressed, as well as the influence of aerodynamics, aeromechanics, and aeroacoustics on the design procedures. Blade fabrication and quality control procedures are detailed; bench testing procedures and results of blade integrity verification are presented; and instrumentation associated with the bench testing also is identified. Additional hardware to support specialized testing is described, as are operating blade instrumentation and the associated stress limits. The five counterrotating blade concepts were scaled to a tip diameter of 2 feet, so they could be incorporated into MPS (model propulsion simulators). Aerodynamic and aeroacoustic performance testing was conducted in the NASA Lewis 8 x 6 supersonic and 9 x 15 V/STOL (vertical or short takeoff and landing) wind tunnels and in the GE freejet anechoic test chamber (Cell 41) to generate an experimental data base for these counterrotating blade designs. Test facility and MPS vehicle matrices are provided, and test procedures are presented. Effects on performance of rotor-to-rotor spacing, angle-of-attack, pylon proximity, blade number, reduced-diameter aft blades, and mismatched rotor speeds are addressed. Counterrotating blade and specialized aeromechanical hub stability test results are also furnished.

Hoff, G. E.↗
NASA NTRS1989

Low-speed aerodynamic characteristics of a powered NASP-like configuration in ground effect

Results are presented on the low-speed aerodynamic characteristics of a simplified NASP (for National Aerospace Plane Program)-like configuration, obtained in the NASA-Langley 14-by-22-foot subsonic tunnel. The model consisted of a triangular wedge forebody, a rectangular midsection housing the propulsion simulation system, and a rectangular wedge aftbody; it also included a delta wing, exhaust flow deflectors, and aftbody fences. Flow visualization was obtained by injecting water into the engine simulator inlets and using a laser light sheet to illuminate the resulting exhaust flow. It was found that power-on ground effects for NASP-like configuration can be substantial; these effects can be reduced by increasing the angle-of-attack to the value of the aftbody ramp angle. Power-on lift losses in ground effect increased with increasing thrust, but could be reduced by the addition of a delta wing to the configuration. Power-on lift losses also increased with use of aftbody fences.

Gatlin, Gregory M.↗
NASA NTRS1991

Enhancing aeropropulsion research with high-speed interactive computing

NASA-Lewis has committed to a long range goal of creating a numerical test cell for aeropropulsion research and development. Efforts are underway to develop a first generation Numerical Propulsion System Simulation (NPSS). The NPSS will provide a unique capability to numerically simulate advanced propulsion systems from nose to tail. Two essential ingredients to the NPSS are: (1) experimentally validated Computational Fluid Dynamics (CFD) codes; and (2) high performing computing systems (hardware and software) that will permit those codes to be used efficiently. To this end, NASA-Lewis is using high speed, interactive computing as a means for achieving Integrated CFD and Experiments (ICE). The development is described of a prototype ICE system for multistage compressor flow physics research.

Szuch, John R.↗
NASA NTRS1990

Ground effects on the low-speed aerodynamics of a powered, generic hypersonic configuration

A study was undertaken in the NASA Langley 14- by 22-foot subsonic tunnel to determine the low-speed aerodynamic characteristics of a powered, generic, hypersonic configuration in ground effect. The model was a simplified configuration consisting of a triangular wedge forebody, a rectangular mid-section which housed the flow through, an ejector type propulsion simulation system, and a rectangular wedge afterbody. Additional model components included a delta wing, a rectangular wedge forebody, inlet fences, exhaust flow deflectors, and afterbody fences. Aerodynamic force and moment data were obtaind over an angle of attack range from -4 to 18 degrees while model height above the tunnel floor was varied from 1/4 inch to 6 feet. Variations in freestream dynamic pressure, from 10 psf to 80 psf, and engine ejector pressure yielded a range of thrust coefficients from 0 to 0.8.

Gatlin, Gregory M.↗
NASA NTRS1991

Enhancing aeropropulsion research with high-speed interactive computing

NASA-Lewis has committed to a long range goal of creating a numerical test cell for aeropropulsion research and development. Efforts are underway to develop a first generation Numerical Propulsion System Simulation (NPSS). The NPSS will provide a unique capability to numerically simulate advanced propulsion systems from nose to tail. Two essential ingredients to the NPSS are: (1) experimentally validated Computational Fluid Dynamics (CFD) codes; and (2) high performing computing systems (hardware and software) that will permit those codes to be used efficiently. To this end, NASA-Lewis is using high speed, interactive computing as a means for achieving Integrated CFD and Experiments (ICE). The development is described of a prototype ICE system for multistage compressor flow physics research.

Szuch, John R.↗
NASA NTRS1992

Flow characterization in the NASA Ames 16-inch Shock Tunnel

Flow characteristics of NASA's 16-Inch Shock Tunnel are determined for purposes of providing hypersonic propulsion simulation capability. The key tunnel operating parameters are the incident shock speed and reservoir pressure and enthalpy. Flow characteristics of concern are the nozzle exit pressure, temperature, Mach number, Reynolds number, chemical composition, and flow uniformity. Surface mounted gages (for pressure and heat transfer) and nonintrusive optical flow diagnostics (emission and absorption spectroscopy and holographic interferometry) are used to verify tunnel conditions. Experimental measurements are used to validate computational analysis for predicting facility performance, and CFD is used to interpret the free stream optical diagnostic measurements.

Cavolowsky, John A.↗
NASA NTRS1994

Program Supplies Properties Of Parahydrogen

National Bureau of Standards Parahydrogen Properties Database (NBS+_PH2) computer program developed to provide selected thermal and transport properties of parahydrogen matching 1981 parahydrogen data of National Bureau of Standards (now called National Institute of Standards and Technology). Created to be linked with propulsion-simulation programs, which require mathematical model of parahydrogen covering wide range of pressures and temperatures. Provides data on parahydrogen for pressures from 10 kPa to 16 MPa and temperatures from 20 to 104 K. Provides following properties: density, thermal conductivity, viscosity, Prandtl number, enthalpy, specific heat, and speed of sound. Written in FORTRAN 77.

Walton, J. T.↗
NASA NTRS1993

Computer program for thermal and transport properties of parahydrogen from 20 to 10,000 K

A computer program was recently developed to provide thermal and transport properties for parahydrogen across a wide temperature and pressure range. The program, NBS+/-pH2, matches the most recent parahydrogen property data from the National Bureau of Standards up to 3000 K and property data from the NASA Lewis Research Center's Chemical Equilibrium Computer Program up to 10,000 K. The pressure range of NBS+/-pH2 is from 1 x 10(exp 4) to 1.6 x 10(exp 7) Pa. The program was developed to meet the need for accurate parahydrogen properties from liquid to dissociated conditions as required by propulsion simulation programs being developed under the Space Exploration Initiative. NBS+/-pH2 is a machine-independent, standard Fortran 77 program which provides density, thermal conductivity, viscosity, Prandtl number, entropy, specific heats, and speed of sound given pressure and either temperature or enthalpy. This program is described and a comparison to programs previously available is provided.

Walton, James T.↗
NASA NTRS1994

Simultaneous three-dimensional velocity and mixing measurements by use of laser Doppler velocimetry and fluorescence probes in a water tunnel

A water tunnel investigation was conducted to demonstrate the capabilities of a laser-based instrument that can measure velocity and fluorescence intensity simultaneously. Fluorescence intensity of an excited fluorescent dye is directly related to concentration level and is used to indicate the extent of mixing in flow. This instrument is a three-dimensional laser Doppler velocimeter (LDV) in combination with a fluorometer for measuring fluorescence intensity variations. This capability allows simultaneous flow measurements of the three orthogonal velocity components and mixing within the same region. Two different flows which were generated by two models were studied: a generic nonaxisymmetric nozzle propulsion simulation model with an auxiliary internal water source that generated a jet flow and an axisymmetric forebody model with a circular sector strake that generated a vortex flow. The off-body flow fields around these models were investigated in the Langley 16- by 24-Inch Water Tunnel. The experimental results were used to calculate 17 quantities that included mean and fluctuating velocities, Reynolds stresses, mean and fluctuating dye fluorescence intensities (proportional to concentration), and fluctuating velocity and dye concentration correlations. An uncertainty analysis was performed to establish confidence levels in the experimental results. In general, uncertainties in mean velocities varied between 1 and 7 percent of free-stream velocity; uncertainties in fluctuating velocities varied between 1 and 5 percent of reference values. The results show characteristics that are unique to each type of flow.

Neuhart, Dan H.↗
NASA NTRS1994

Dual-Use Space Technology Transfer Conference and Exhibition, Volume 1

This document contains papers presented at the Dual-Use Space Technology Transfer Conference and Exhibition held at the Johnson Space Center February 1-3, 1994. Possible technology transfers covered during the conference were in the areas of information access; innovative microwave and optical applications; materials and structures; marketing and barriers; intelligent systems; human factors and habitation; communications and data systems; business process and technology transfer; software engineering; biotechnology and advanced bioinstrumentation; communications signal processing and analysis; new ways of doing business; medical care; applications derived from control center data systems; human performance evaluation; technology transfer methods; mathematics, modeling, and simulation; propulsion; software analysis and decision tools systems/processes in human support technology; networks, control centers, and distributed systems; power; rapid development perception and vision technologies; integrated vehicle health management; automation technologies; advanced avionics; ans robotics technologies. More than 77 papers, 20 presentations, and 20 exhibits covering various disciplines were presented b experts from NASA, universities, and industry.

Kumar Krishen↗
NASA NTRS1994

Dual-Use Space Technology Transfer Conference and Exhibition

This is the second volume of papers presented at the Dual-Use Space Technology Transfer Conference and Exhibition held at the Johnson Space Center February 1-3, 1994. Possible technology transfers covered during the conference were in the areas of information access; innovative microwave and optical applications; materials and structures; marketing and barriers; intelligent systems; human factors and habitation; communications and data systems; business process and technology transfer; software engineering; biotechnology and advanced bioinstrumentation; communications signal processing and analysis; medical care; applications derived from control center data systems; human performance evaluation; technology transfer methods; mathematics, modeling, and simulation; propulsion; software analysis and decision tools; systems/processes in human support technology; networks, control centers, and distributed systems; power; rapid development; perception and vision technologies; integrated vehicle health management; automation technologies; advanced avionics; and robotics technologies.

Krishen, Kumar↗
NASA NTRS1998

The Real-Time Wall Interference Correction System of the NASA Ames 12-Foot Pressure Wind Tunnel

An improved version of the Wall Signature Method was developed to compute wall interference effects in three-dimensional subsonic wind tunnel testing of aircraft models in real-time. The method may be applied to a full-span or a semispan model. A simplified singularity representation of the aircraft model is used. Fuselage, support system, propulsion simulator, and separation wake volume blockage effects are represented by point sources and sinks. Lifting effects are represented by semi-infinite line doublets. The singularity representation of the test article is combined with the measurement of wind tunnel test reference conditions, wall pressure, lift force, thrust force, pitching moment, rolling moment, and pre-computed solutions of the subsonic potential equation to determine first order wall interference corrections. Second order wall interference corrections for pitching and rolling moment coefficient are also determined. A new procedure is presented that estimates a rolling moment coefficient correction for wings with non-symmetric lift distribution. Experimental data obtained during the calibration of the Ames Bipod model support system and during tests of two semispan models mounted on an image plane in the NASA Ames 12 ft. Pressure Wind Tunnel are used to demonstrate the application of the wall interference correction method.

Ulbrich, Norbert↗