Search NASA⌕ Search

SEARCH · Search NASA

Results for “ARC JET”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Characterization of the thermal conductivity for fibrous refractory composite insulations

Thermal conductivity for a family of fibrous, refractory composite insulations are characterized through the use of an engineering model and arc-jet data. The model defines the composite as a uniform pore material using measured physical and mechanical properties. Efficiency parameters assigned to the solid and radiation conduction terms in the thermal conductivity equation were found to be dependent only on solid volume fraction and porosity.

Stewart, D. A.↗
NASA NTRS1986

Spectral measurement of the Space Shuttle leeside shock layer and wake

Leeside shock layer and wake spectral radiation measured during the high altitude portion of the reentry of Space Shuttle Orbiter STS 51-D are presented and are compared with similar measurements obtained in an arc jet tunnel. The spectra, measured with a low-resolution spectral camera, are compared in order to identify the radiating species in a wavelength range from 4000 to 8000 angstroms. Emissions identified are: N2 first positive and N2 second positive systems, the N2(+) first negative system, and the sodium-D lines. No atomic air species or CN are observed. The spectra and procedure will be of use in comparison of flight flowfield properties with computational predictions and for guidance in developing future flight experiments.

Blackwell, H. E.↗
NASA NTRS1987

Wind-Tunnel Capability at Ames Research Center

Report describes $700 million wind-tunnel complex at Ames Research Center, including auxiliary support systems, test instrumentation, and special test rigs. Planned near-term facility improvement aimed at providing new test capabilities and increased productivity, as well as some potential longer-term improvements, also discussed. Aerodynamic test facilities range from subsonic wind tunnels to highenthalpy arc jets.

Snyder, C. T.↗
NASA NTRS1987

CSCM methodology for slot injection cooled cavity flow design in a high enthalpic stream

The CSCM method for the compressible Navier-Stokes equations is applied to study design factors in a slot injection cooled cavity flow in the side of a 2-D wedge body in a high enthalpy free stream. The flow geometry is being designed and will be tested in an arc jet tunnel at NASA-Ames Research Center. Objectives of the design are to provide adequate thermal protection for and minimize aero-optical distortion in the path above a window located in the bottom of the cavity. Among design issues, are the geometry of and flow conditions in the expanding section of the supersonic slot injection nozzle. Here, for straight walled nozzles, two geometries are considered for the upper nozzle lip between the hot, high speed outer flow and the colder, denser cooling flow. The two lip geometries - thick, square and thin, wedge - as the result of associated widely differing base/wake flows also exhibit different and interesting viscous-inviscid flow structures near the ramp termination to the cavity. For the thin lip case, the consequences on flow quality of off design nozzle conditions relative to matching pressure with the outer flow are explored.

Bardina, Jorge↗
NASA NTRS1987

Spectral determination of nitrogen vibrational temperatures

A technique for determining the vibrational temperature of nitrogen molecules is found from the emission of the N2 first positive spectrum. The technique involves calculating wavelength integrals of portions of the emission spectrum associated with transitions from the ststes B3Pi(g)(v-prime) to A3 Sigma(u +)(v-double prime) where Delta = 2, 3, etc. Ratios of the integrated intensities are then correlated with vibrational temperature. The dependence of the technique on rotational temperature is considered and less dependence is obtained if the overlap between Delta v-regions is accounted for. The technique is applied to the shock layer of a blunt body in an arc jet flow. The N2(1+) spectrum is measured in the shock layer to obtain the intensity integral ratios. From these ratios estimates of the vibrational temperature are found from the correlation which agree quite well with calculated temperatures in the shock layer flow.

Blackwell, Harvel E.↗
NASA NTRS1987

Nitrogen recombination on high-temperature reusable surface insulation and the analysis of its effect on surface catalysis

The energy transfer catalytic recombination coefficients for nitrogen and oxygen on a borosilicate glass are determined in nitrogen and air hypersonic arc jet streams. These data, obtained from a reacting boundary-layer analysis with first-order surface reaction kinetics, compare well with earlier results from a Goulard frozen boundary-layer model up to 1600 K. The apparent surface recombination rates increase up to 1600 K, then begin to decrease. To illustrate the effects of temperature and nitrogen dissociation on energy transfer to the glass, a diffusional heat-flux is calculated using the present results from 1450 K up to 1850 K. This diffusional heat-flux is the contribution to the total heating rate by atom recombination, and is used to compare the present results with coefficients from three previous studies.

Kolodziej, Paul↗
NASA NTRS1988

Analytical and experimental validation of the Oblique Detonation Wave Engine concept

The Oblique Detonation Wave Engine (ODWE) for hypersonic flight has been analytically studied by NASA using the CFD codes which fully couple finite rate chemistry with fluid dynamics. Fuel injector designs investigated included wall and strut injectors, and the in-stream strut injectors were chosen to provide good mixing with minimal stagnation pressure losses. Plans for experimentally validating the ODWE concept in an arc-jet hypersonic wind tunnel are discussed. Measurements of the flow field properties behind the oblique wave will be compared to analytical predictions.

Adelman, Henry G.↗
NASA NTRS1988

Wall catalysis experiment on AFE

This paper describes the wall catalysis experiment which is planned as part of the Aeroassist Flight experiments (AFE) that will be flown from the Space Shuttle Orbiter in late 1993. Research on candidate high-catalytic efficiency overcoats for the experiment conducted in an arc-jet air stream are discussed. The temperature distribution over the AFE heat shield is also predicted using a reacting boundary layer solution that includes surface kinetics and optical properties determined from these tests.

Stewart, David A.↗
NASA NTRS1989

AFE ion mass spectrometer design study

This final technical report covers the activities engaged in by the University of Texas at Dallas, Center for Space Sciences in conjunction with the NASA Langley Research Center, Systems Engineering Division in design studies directed towards defining a suitable ion mass spectrometer to determine the plasma parameter around the Aeroassisted Flight Experiment vehicle during passage through the earth's upper atmosphere. Additional studies relate to the use of a Langmuir probe to measure windward ion/electron concentrations and temperatures. Selected instrument inlet subsystems were tested in the NASA Ames Arc-Jet Facility.

Wright, Willie↗
NASA NTRS1989

Experimental program for real gas flow code validation at NASA Ames Research Center

The experimental program for validating real gas hypersonic flow codes at NASA Ames Rsearch Center is described. Ground-based test facilities used include ballistic ranges, shock tubes and shock tunnels, arc jet facilities and heated-air hypersonic wind tunnels. Also included are large-scale computer systems for kinetic theory simulations and benchmark code solutions. Flight tests consist of the Aeroassist Flight Experiment, the Space Shuttle, Project Fire 2, and planetary probes such as Galileo, Pioneer Venus, and PAET.

Deiwert, George S.↗
NASA NTRS1989

Temperature determination of shock layer using spectroscopic techniques

Shock layer temperature profiles are obtained through analysis of radiation from shock layers produced by a blunt body inserted in an arc jet flow. Spectral measurements of N2(+) have been made at 0.5 inch, 1.0 inch, and 1.4 inches from the blunt body. A technique is developed to measure the vibrational and rotational temperatures of N2(+). Temperature profiles from the radiation layers show a high temperature near the shock front and decreasing temperature near the boundary layer. Precise temperature measurements could not be made using this technique due to the limited resolution. Use of a high resolution grating will help to make a more accurate temperature determination. Laser induced fluorescence technique is much better since it gives the scope for selective excitation and a better spacial resolution.

Akundi, Murty A.↗
NASA NTRS1990

Transatmospheric vehicle research

Research was conducted into the alternatives to the supersonic combustion ramjet (scramjet) engine for hypersonic flight. A new engine concept, the Oblique Detonation Wave Engine (ODWE) was proposed and explored analytically and experimentally. Codes were developed which can couple the fluid dynamics of supersonic flow with strong shock waves, with the finite rate chemistry necessary to model the detonation process. An additional study was conducted which compared the performance of a hypersonic vehicle powered by a scramjet or an ODWE. Engineering models of the overall performances of the two engines are included. This information was fed into a trajectory program which optimized the flight path to orbit. A third code calculated the vehicle size, weight, and aerodynamic characteristics. The experimental work was carried out in the Ames 20MW arc-jet wind tunnel, focusing on mixing and combustion of fuel injected into a supersonic airstream. Several injector designs were evaluated by sampling the stream behind the injectors and analyzing the mixture with an on-line mass spectrometer. In addition, an attempt was made to create a standing oblique detonation wave in the wind tunnel using hydrogen fuel. It appeared that the conditions in the test chamber were marginal for the generation of oblique detonation waves.

Adelman, Henry G.↗
NASA NTRS1990

High power arcjet

The activities on the development of the high power arc jet HIPARC, the thrust balance, and plasma diagnostic probes are discussed. Modifications of the HIPARC design and a synopsis of the materials used are given. Further experimental results with the TT30 thruster in the 50 kW range are presented. Some first calibration measurements of the thrust balance are also included. Progress concerning the development of plasma diagnostic devices is documented.

Auweter-Kurtz, M.↗
NASA NTRS1990

Qualification and life testing of a flight design hydrazine arcjet system

This paper describes the design and the requirements of a low-power hydrazine arc jet system and presents the results of tests on the system's performance, vibration, and lifetime. The system consists of an arcjet, catalyst bed, power control unit, and interconnecting power cable. Operating at 1.4 kW input power, the system provides a minimum of 450 sec mission average specific impulse, yielding greater than a 100 kg propellant savings over standard monopropellant or bipropellant systems used on communication satellites.

Knowles, S. C.↗
NASA NTRS1990

Space technology test facilities at the NASA Ames Research Center

The major space research and technology test facilities at the NASA Ames Research Center are divided into five categories: General Purpose, Life Support, Computer-Based Simulation, High Energy, and the Space Exploraton Test Facilities. The paper discusses selected facilities within each of the five categories and discusses some of the major programs in which these facilities have been involved. Special attention is given to the 20-G Man-Rated Centrifuge, the Human Research Facility, the Plant Crop Growth Facility, the Numerical Aerodynamic Simulation Facility, the Arc-Jet Complex and Hypersonic Test Facility, the Infrared Detector and Cryogenic Test Facility, and the Mars Wind Tunnel. Each facility is described along with its objectives, test parameter ranges, and major current programs and applications.

Gross, Anthony R.↗
NASA NTRS1991

Thermographic monitoring of materials under simulated reentry conditions

Thermography can be used to measure surface temperature gradients graphically, and can be used under conditions where the direct measurement of temperature at all desired points, using thermocouples or resistance temperature detectors (RTDs), is either difficult or impossible. The use of thermographic monitoring during a series of arc-jet tests is described. Described in this work are the issues that influence interpretation of the thermographic measurements under these conditions, including the calculation of effective emittance and window transmittance from the spectral properties of the materials in order to calculate the temperature distribution of a surface directly from the measured radiance. Comparison of the surface temperatures measured using thermocouples and the temperatures derived from thermographic measurements show good agreement. The data gathered will be used to evaluate important test parameters such as the heating distribution across the surface of a heat shield test model and at steps on the model surface.

White, Susan M.↗
NASA NTRS1990

Keyhole and weld shapes for plasma arc welding under normal and zero gravity

A first order study of the interfacial (keyhole) shape between a penetrating argon plasma arc jet and a stationary liquid metal weld pool is presented. The interface is determined using the Young-Laplace equation by assuming that the plasma jet behaves as a one-dimensional ideal gas flow and by neglecting flow within the weld pool. The solution for the keyhole shape allows an approximate determination of the liquid-solid metal phase boundary location based on the assumption that the liquid melt is a stagnant thermal boundary layer. Parametric studies examine the effect of plasma mass flow rate, initial plasma enthalpy, liquid metal surface tension, and jet shear on weldment shape under both normal and zero gravity. Among the more important findings of this study is that keyhole and weld geometries are minimally affected by gravity, suggesting that data gathered under gravity can be used in planning in-space welding.

Keanini, R. G.↗