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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 271 records · Page 15

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NASA NTRS1973

Property investigation and sputter deposition of dispersion-hardened copper for fatigue specimen fabrication

Sputter-deposited alloys of dispersion-hardenable Cu-0.25 vol% SiC and Cu-0.50 vol% SiC and precipitation-hardenable Cu-0.15 wt% Zr and Cu-0.05 wt% Mg-0.15 wt% Zr-0.40 wt% Cr were investigated for selection to evaluate fatigue specimen performance with potential application in fabricating regeneratively cooled rocket thrust chambers. Yield strengths in the 700 to 1000-MN/sq m range were observed with uniform elongation ranging from 0.5 to 1.5% and necking indicative of greater ductility. Electrical conductivity measured as an analog to thermal conductivity gave values 90% IACS for Cu-0.15 wt% Zr and Cu-0.05 wt% Mg-0.15 wt% Zr-0.40 wt% Cr. A 5500-g sputtered deposit of Cu-0.15 wt% Zr alloy, 12.29 mm (0.484 in.) average thickness in the fatigue specimen gage length, was provided to NASA on one of their substrates.

Mcclanahan, E. D.↗

NASA NTRS1974

Numerical solution of the steady-state Navier-Stokes equations for hypersonic flow about blunt axisymmetric bodies

The steady-state Navier-Stokes equations are solved for hypersonic flow about blunt axisymmetric bodies. The equations of motion are solved by successive approximations using an implicit finite-difference scheme. The results are compared with viscous shock-layer theory, experimental data, and time-dependent solutions of the Navier-Stokes equations. It is demonstrated that viscous shock-layer theory is sufficiently accurate for the range of flight conditions normally encountered by entry vehicles.

Anderson, E. C.↗

NASA NTRS1974

The effect of ablation injection on radiative and convective heating

A viscous shock-layer analysis is for calculating high energy equilibrium flow fields about blunt axisymmetric bodies is applied to the problem of massive ablation injection with radiation transport. A nongray radiation model is used that accounts for both line and continuum radiation. The solution method is direct and provides both stagnation and downstream solutions. Results for shock heated air show that phenolic-nylon injection is substantially more effective in reducing the wall radiant flux than air injection. Also, for large included body angles, the wall radiative flux and the coupled phenolic-nylon injection rate do not continue to decrease with increasing distance downstream.

Moss, J. N.↗

NASA NTRS1974

Investigation of the stall-induced shock wave (hammershock) at the inlet to the engine

The peak static pressures measured at the inlet to the engine during stall are presented for a turbojet and two turbofan engines. It is shown for one turbofan and the turbojet that the static pressure ratio across the hammershock does not exceed significantly the normal shock pressure ratio necessary to stop the flow. The second turbofan engine did not follow this rule. Possible reasons for the departure are discussed. For the two turbofan engines the influence of the stall method on the hammershock intensity was investigated. Data related to the spatial distribution of pressure in the hammershock are also presented.

Kurkov, A. P.↗

NASA NTRS1974

Stagnation and downstream viscous shock-layer solutions with radiation and coupled ablation injection

This paper describes a rigorous viscous shock-layer analysis for investigating high energy equilibrium flow fields about blunt axisymmetric bodies. The analysis includes radiation transfer, mass injection, diffusion, and viscous effects. Radiation transfer is calculated with a nongray radiation model that accounts for line and continuum radiation. The analysis can treat all levels of blowing for both stagnation and downstream flow. Results are presented for selected earth entry conditions that demonstrate the essential features of this analysis. Particular emphasis is given to the effects of mass injection on stagnation and downstream flow. Results for both specified and coupled ablation injection are presented.

Moss, J. N.↗

NASA NTRS1974

Investigation of the stall-induced shock wave /hammershock/ at the inlet to the engine

The peak static pressures measured at the inlet to the engine during stall are presented for a turbojet and two turbofan engines. It is shown for one turbofan and the turbojet that the static pressure ratio across the hammershock does not exceed significantly the normal shock pressure ratio necessary to stop the flow. The second turbofan engine did not follow this rule. Possible reasons for the departure are discussed. For the two turbofan engines, the influence of the stall method on the hammershock intensity has been investigated. Data related to the spatial distribution of pressure in the hammershock are also presented.

Kurkov, A. P.↗

NASA NTRS1972

Preliminary design of a Primary Loop Pump Assembly (PLPA), using electromagnetic pumps

A preliminary design study of flight-type dc conduction-permanent magnetic, ac helical induction, and ac linear induction pumps for circulating 883 K (1130 F) NaK at 9.1 kg/sec (20 lb/sec) is described. Various electromagnetic pump geometrics are evaluated against hydraulic performance, and the effects of multiple windings and numbers of pumps per assembly on overall reliability were determined. The methods used in the electrical-hydraulic, stress, and thermal analysis are discussed, and the high temperature electrical materials selected for the application are listed.

Moss, T. A.↗

NASA NTRS1975

Numerical solution of the hypersonic viscous-shock-layer equations for laminar, transitional, and turbulent flows of a perfect gas over blunt axially symmetric bodies

The viscous shock layer equations applicable to hypersonic laminar, transitional, and turbulent flows of a perfect gas over two-dimensional plane or axially symmetric blunt bodies are presented. The equations are solved by means of an implicit finite difference scheme, and the results are compared with a turbulent boundary layer analysis. The agreement between the two solution procedures is satisfactory for the region of flow where streamline swallowing effects are negligible. For the downstream regions, where streamline swallowing effects are present, the expected differences in the two solution procedures are evident.

Anderson, E. C.↗

NASA NTRS1975

Effect of casing treatment on performance of a multistage compressor

AJ85-GE-13 engine was equipped with a compressor case which allowed changes to the case wall over the rotor tips of six of its stages. The engine was tested with four inlet configurations: undistorted and with 180 deg circumferential, hub radial, and tip radial distortions. Baseline data defining compressor performance and stall regions were taken for these inlet configurations with solid (untreated) compressor case inserts. Circumferentially grooved inserts were installed in the first three and last three stages, and the compressor was mapped under similar conditions. The compressor was mapped a third time with untreated inserts in the first three stages and inserts having slots conforming to blade angles in the last three stages. In most cases, the stall pressure ratio was the same as or lower than the baseline. Pumping capacity with the slotted inserts was reduced. Overall compressor efficiency with the grooved rings installed did not appreciably differ from the baseline, but it was 1 to 2 percentage points lower than the baseline with the slotted rings in place. Average stage characteristics for the undistorted inlet case showed little or no sensitivity to casing treatment.

Wenzel, L. M.↗

NASA NTRS1975

Challenge to Aviation: Hatching a Leaner Pterosauer

Modifications in commercial aircraft design, particularly the development of lighter aircraft, are discussed as effective means of reducing aviation fuel consumption. The modifications outlined include: (1) use of the supercritical wing; (2) generation of the winglet; (3) production and flight testing of composite materials; and, (4) implementation of fly-by-wire control systems. Attention is also given to engineering laminar air flow control, improving cargo payloads, and adapting hydrogen fuels for aircraft use.

Moss, F. E.↗

NASA NTRS1975

Viscous-shock-layer solutions for turbulent flow of radiating gas mixtures in chemical equilibrium

The viscous-shock-layer equations for hypersonic laminar and turbulent flows of radiating or nonradiating gas mixtures in chemical equilibrium are presented for two-dimensional and axially-symmetric flow fields. Solutions were obtained using an implicit finite-difference scheme and results are presented for hypersonic flow over spherically-blunted cone configurations at freestream conditions representative of entry into the atmosphere of Venus. These data are compared with solutions obtained using other methods of analysis.

Anderson, E. C.↗

NASA NTRS1975

Viscous-shock-layer solutions with radiation and ablation injection for Jovian entry

This paper presents results that describe the flow field and surface response conditions for a planetary probe entering the atmosphere of Jupiter. The results are obtained with a viscous-shock-layer analysis which includes mass injection, radiative transfer, diffusion, and viscous effects. Radiative transfer is calculated with an existing nongray radiation model that accounts for molecular band, atomic line, and continuum transitions. Particular emphasis is given to the effect of mass injection on the stagnation and downstream flow. Results for both specified and coupled mass injection are obtained for a carbon heat shield.

Moss, J. N.↗

NASA NTRS1975

Outer planet entry probes aerothermal environment - Status of prediction methodology

A description is given of the computational codes that are to be used in studies of the heating and aerodynamic performance of entry probes for the scientific exploration of the planets Jupiter, Saturn, and Uranus. These codes include a time-asymptotic numerical method which takes into account radiative transport and equilibrium chemistry for the direct solution of the radiative, inviscid flow over an axisymmetric or two-dimensional body. The method considers both supersonic and subsonic flow in the downstream region. Another code represents a laminar, viscous-shock-layer solution.

Sutton, K.↗

NASA NTRS1975

Viscous shock layer solutions for turbulent flow of radiating gas mixtures in chemical equilibrium

The viscous shock layer equations for hypersonic laminar and turbulent flows of radiating or nonradiating gas mixtures in chemical equilibrium are presented for two-dimensional and axially symmetric flow fields. Solutions are obtained using an implicit finite difference scheme and results are presented for hypersonic flow over spherically blunted cone configurations at free stream conditions representative of entry into the atmosphere of Venus. These data are compared with solutions obtained using other methods of analysis.

Anderson, E. C.↗

NASA NTRS1976

Effect of slotted casing treatment on performance of a multistage compressor

A J85-13 engine was equipped with a compressor case that allowed changes to the case wall over the rotor tips of six of its eight stages. The engine was tested with four inlet configurations: uniform inlet flow, 180 degree circumferential distortion, hub radial distortion, and tip radial distortion. Slotted inserts were installed in the first three stages, and the compressor was mapped under similar conditions. Overall compressor performance obtained with tip treatment was inferior to the performance for the compressor's normal operating range. Pumping capacity with the slotted inserts was reduced. Overall compressor efficiency was reduced 1 to 2 percent with the slotted rings installed for 90 and 100 percent corrected engine speeds.

Moss, J. E., Jr.↗

NASA NTRS1976

Turbulent viscous-shock-layer solutions with strong vorticity interaction

Numerical solutions of the viscous-shock-layer equations governing laminar and turbulent flows of a perfect gas and radiating and nonradiating mixtures of perfect gases in chemical equilibrium are presented for hypersonic flow over spherically blunted cones and hyperboloids. The results are compared with boundary-layer and inviscid flow-field solutions. The agreement with the inviscid flow field data is satisfactory. The agreement with boundary-layer solutions is good except in regions of strong vorticity interaction. In these flow regions, the viscous-shock-layer solutions appear to be more satisfactory than the boundary-layer solutions.

Anderson, E. C.↗

NASA NTRS1976

Aerothermal environment for Jovian entry probes

Results are presented that describe the aerothermal environment encountered by the forebody of probes during Jovian entry. Two probe configurations are considered: a 55 deg half-angle spherically blunted cone and a 50 deg half-angle hyperboloid. The main emphasis is focused on defining the heating environment during entry and on determining the effectiveness of coupled ablation injection in reducing the surface heating rate. This is accomplished by calculating both the convective and radiative heating at several points along the entry trajectory both with and without coupled ablation injection. Results are presented for both laminar and turbulent calculations.

Moss, J. N.↗

NASA NTRS1976

An investigation of the effects of mass loss, shape change and real gas aerodynamics on a Jovian atmospheric reconstruction experiment

A survey of the effects of mass loss, shape change and real-gas aerodynamics on a Jovian atmospheric reconstruction experiment is carried out. Techniques used to reconstruct atmospheric profiles from entry probe measurements are discussed and some of the parameters which affect their accuracy are identified. Trajectory analyses and real-gas, radiatively-coupled flow field analyses (which include the effects of mass loss and shape change) are carried out for several candidate probe configurations. From these analyses, uncertainties in the atmospheric reconstruction procedure are estimated. Finally, the prospects for reducing these uncertainties by optimizing probe configuration and by instrumentation of the probe heat shield to measure actual shape change are considered.

Walberg, G. D.↗