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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 829 records · Page 46
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Compressor cascade performance deterioration caused by sand ingestion

Airfoil cascade erosion and performance deterioration was investigated in a gas particle cascade tunnel. The cascade blades were made of 2024 aluminum alloy and the solid particles used were quartz sand. The results of the experimental measurements are presented to show the change in the blade surface erosion, pressure distribution and the total loss coefficient with erosion. The surface quality of the blades exposed to particulate flows are changing the material surfaces. With time, the surface roughness increases and leads to a decrease in engine performance. It was found that the surface roughness values increase asymptotically to a maximum value with increased erosion. The experimental results indicate that the roughness parameters correlate well against the mass of particles impacting unit area of the surface. Such a correlation is useful in aerodynamics and performance computations in turbomachinery.

Tabakoff, W.↗
NASA NTRS1983

Numerical computation of transonic flow governed by the full-potential equation

Numerical solution techniques for solving transonic flow fields governed by the full potential equation are discussed. In a general sense relaxation schemes suitable for the numerical solution of elliptic partial differential equations are presented and discussed with emphasis on transonic flow applications. The presentation can be divided into two general categories: An introductory treatment of the basic concepts associated with the numerical solution of elliptic partial differential equations and a more advanced treatment of current procedures used to solve the full potential equation for transonic flow fields. The introductory material is presented for completeness and includes a brief introduction (Chapter 1), governing equations (Chapter 2), classical relaxation schemes (Chapter 3), and early concepts regarding transonic full potential equation algorithms (Chapter 4).

Holst, T. L.↗
NASA NTRS1983

Thermomechanical loading of multilayered cylindrical geometries in thermal cycling from 300 to 1300 K

The principal of multiple material layering is well known as an effective method of reducing heat transfer; however, thermal gradients can impose significant loads and lead to delamination and subsequent component failure. An analysis is developed and experimental data are discussed for the thermomechanical effects of multilayered materials on a heat sink substrate of cylindrical geometry subject to thermal cycling. The geometry is heated in cross-flow by a high-velocity flame and cooled in crossflow by ambient-temperature air from a critical flow orifice. Each layer of material possesses a threshold beyond which small changes in temperature or mechanical loading greatly influence the life in thermal cycling of the layered materials. Comparisons are made between the thermomechanical loads predicted by various numerical codes for the linear case and by a simplified analytic model.

Hendricks, R. C.↗
NASA NTRS1983

Two hundred passage three-way valve: Fraction collector

This paper describes the design and operation of a fraction collector used to direct flow of separated biological materials from 197 capillary tubes to either a collection tray or to a waste tank. This mechanism uses a 28-volt dc gear motor driving twin cams to force 197 needles through a self-sealing silicone rubber septum, where they inject the material in 197 separate pockets in a collection tray. The position of the collector tray is sensed by two optical limit switches. The time sequences are controlled automatically by an electronics control monitoring module.

Keffer, J. L.↗
NASA NTRS1983

The Trend of Future Gas Turbine Technology

Turbomachinery system component research to advance the technology of aviation turbofan and turbojet engines is discussed. Areas of research include compressors, turbines, internal flow analysis, combustion, fuels, materials, structures, bearings, seals, lubrication, dynamics and controls, and instrumentation. A review of the research directions being taken in these areas and the steady advances being made provides a reasonable glimpse at gas turbine technology of the future.

Hartman, M. J.↗
NASA NTRS1984

Mass loss from the proto-sun - Formation and evolution of the solar nebula

It is argued that the solar nebula and hence the planetary system were formed from the mass ejected by the protosun, whose strong magnetic field controlled the azimuthal and radial flow of the ejected material. The formation and evolution of the solar nebula is discussed in the light of observations of T Tauri stars, oxygen-isotopic anomalies in meteorites, and the mass and angular momentum distribution in the present solar system.

Trivedi, B. M. P.↗
NASA NTRS1984

Helical twisting on an adiabatically expanding jet. I Propagation and temporal growth

The local linearized dispersion relation for perturbations to the surface of a constantly adiabatic jet, which is assumed to be in static pressure balance with an isothermal confining medium, is derived in an investigation of the effect of adiabatic expansion on the propagation and temporal growth of helical twisting in a supersonic jet. Cooling of the jet material along such a flow increases Mach number and relative density relative to the confining medium, as distance from the origin increases; this leads to a rather rapid decrease in the maximum rate of growth and an increase in the maximally unstable wavelength, relative to the jet's radius, as the distance along such a jet increases. Attention is given to the consequences of assuming that a change in the phase velocity of a propagating helical wave along a jet causes the wavelength of a helical wave to change.

Hardee, P. E.↗
NASA NTRS1984

The trend of future gas turbine technology

Future gas turbine technology will be based on contributions to the technology base being made today. At the NASA Lewis Research Center in Cleveland, OH, research is being conducted on turbomachinery system components and in a number of associated disciplines to advance the technology of aviation turbofan and torbojet engines. Areas of research include compressors, turbines, internal flow analysis, combustion, fuels, materials, structures, bearings, seals, lubrication, dynamics and controls, and instrumentation. A review of the research directions being taken in these areas and the steady advances being made provides a reasonable glimpse at gas turbine technology of the future.

Hartmann, M. J.↗
NASA NTRS1985

Emission in the hydrogen-Brackett lines of Epsilon Aurigae during eclipse

Results of high-resolution infrared spectroscopy of Epsilon Aur performed from 1982 and 1985 in order to investigate the effects of eclipse on spectral lines at near-infrared wavelengths are reported. The profiles of the Brackett-alpha and Brackett-gamma lines of hydrogen are reported. The B-alpha emission has an integrated flux of 9 x 10 to the -15th W/sq m, a FWHM of 60 km/s, and a radial velocity that follows the predicted velocity curve of the primary star more closely than that of the secondary. The mean B-alpha/B-gamma flux ratio was approximately unity on the three dates both lines were observed, indicating optically thick emission. It is concluded that the emission originates in a flow rather than from material in Keplerian revolution; the Brackett line emission probably has the same source as the previously observed H-alpha emission.

Backman, D. E.↗
NASA NTRS1985

ICIASF '85 - International Congress on Instrumentation in Aerospace Simulation Facilities, 11th, Stanford University, CA, August 26-28, 1985, Record

Developments related to laser Doppler velocimetry are discussed, taking into account a three-component dual beam laser-Doppler-anemometer to be operated in large wind tunnels, a new optical system for three-dimensional laser-Doppler-anemometry using an argon-ion and a dye laser, and a two-component laser Doppler velocimeter by switching fringe orientation. Other topics studied are concerned with facilities, instrumentation, control, hot wire/thin film measurements, optical diagnostic techniques, signal and data processing, facilities and adaptive wall test sections, data acquisition and processing, ballistic instrument systems, dynamic testing and material deformation measurements, optical flow measurements, test techniques, force measurement systems, and holography. Attention is given to nonlinear calibration of integral wind tunnel balances, a microcomputer system for real time digitized image compression, and two phase flow diagnostics in propulsion systems.

Source record↗
NASA NTRS1987

History and morphology of faulting in the Noctis Labyrinthus-Claritas Fossae Region of Mars

The topographically high areas cut by Noctis Labyrinthus, Noctis Fossae, and Claritas Fossae were subjected to only minor resurfacing during and following local tectonic activity. Principal resurfacing materials consist of lava flows from Syria Planum and Tharsis Montes. Thus, these areas preserve much of the fault record produced by tectonism in this region. Although recent geologic maps of the area have been produced from Viking images, the only detailed fault histories available until now were described from Mariner 9 images. Much of the faulting in the Tharsis tectonic province was centered in Syria Planum; therefore, understanding the fault history in this region is critical to understanding the stress history and tectonism of Tharsis as a whole.

Tanaka, Kenneth L.↗
NASA NTRS1986

Detection of a 'rotating' gas cloud 100 kiloparsecs in diameter surrounding 3C 275.1, a quasar at the center of a rich cluster of galaxies

The distorted radio quasar 3C 275.1 (z = 0.55) is the first QSO found to lie at the center of a rich cluster of galaxies. The quasar is surrounded by an extremely large elliptical nebulosity whose major axis exceeds 100 kpc. Spectroscopic observations of this nebulosity were obtained, with the spectrograph slit aligned along the nebulosity's major axis. The spectrum of the nebulosity in the visible is dominated by O II and O III forbidden emission lines, which yield a well-defined 'solid-body rotation curve' extending 40 kpc from the quasar nucleus, a rotation curve very different from those of normal spiral galaxies. The 3C 275.1 nebulosity is both the largest yet discovered around a quasar and the first in which organized large-scale motions (rotation?) have been identified. The nebulosity may be residue from multiple tidal interactions with cluster members, or it may be accumulated material from a 'cooling flow' of the type seen in low-redshift clusters which are X-ray sources.

Hintzen, P.↗
NASA NTRS1988

Optical Detection Of Cryogenic Leaks

Conceptual system identifies leakage without requiring shutdown for testing. Proposed device detects and indicates leaks of cryogenic liquids automatically. Detector makes it unnecessary to shut equipment down so it can be checked for leakage by soap-bubble or helium-detection methods. Not necessary to mix special gases or other materials with cryogenic liquid flowing through equipment.

Wyett, Lynn M.↗
NASA NTRS1987

High power lasers: Sources, laser-material interactions, high excitations, and fast dynamics in laser processing and industrial applications; Proceedings of the Meeting, The Hague, Netherlands, Mar. 31-Apr. 3, 1987

The design and operation of high-power lasers for industrial applications are discussed in reviews and reports. Topics addressed include the status of optical technology in the Netherlands, laser design, the deposition of optical energy, laser diagnostics, nonmetal processing, and energy coupling and plasma formation. Consideration is given to laser-induced damage to materials, fluid and gas flow dynamics, metal processing, and manufacturing. Graphs, diagrams, micrographs, and photographs are provided.

Kreutz, E. W.↗
NASA NTRS1987

High power CW iodine laser pumped by solar simulator

An iodine photodissociation laser was pumped by a long Ar arc as the solar simulator to produce a 10-W CW output. Continuous lasing for 1 h was achieved with a flow of the laser material n-C3F7I. The 10-W CW output is the highest produced to date and establishes the feasibility of developing a solar-pumped laser for space power transmission.

Lee, Ja H.↗
NASA NTRS1991

Chemical fractionation of siderophile elements in impactites from Australian meteorite craters

The abundance pattern of siderophile elements in terrestrial and lunar impact melt rocks was used extensively to infer the nature of the impacting projectiles. An implicit assumption made is that the siderophile abundance ratios of the projectiles are approximately preserved during mixing of the projectile constituents with the impact melts. As this mixture occurs during flow of strongly shocked materials at high temperatures, however there are grounds for suspecting that the underlying assumption is not always valid. In particular, fractionation of the melted and partly vaporized material of the projectile might be expected because of differences in volatility, solubility in silicate melts, and other characteristics of the constituent elements. Impactites from craters with associated meteorites offer special opportunities to test the assumptions on which projectile identifications are based and to study chemical fractionation that occurred during the impact process.

Attrep, A., Jr.↗
NASA NTRS1992

ASRM plume deflector analysis program

This paper presents analytical conclusions resulting from subscale solid rocket motor tests and flowfield modeling for a plume deflector. Loads, flow characteristics, and corresponding material behavior were predicted or observed and will be used in final design of the deflector. The efforts resulted in quantifiable size reductions and lower cost material selections, which will significantly reduce the deflector cost while meeting performance requirements.

Dawson, Michael C.↗
NASA NTRS1992

Pancakelike domes on Venus

The shape of seven large domes on the plains of Venus, with volumes between 100 and 1000 cu km, is compared with that of an axisymmetric gravity current spreading over a rigid horizontal surface. Both the altimetric profiles and the horizontal projection of the line of intersection of domes on the SAR images agree well with the theoretical similarity solution for a newtonian fluid, but not with the shape calculated for a rigid-plastic rheology, nor with that for a static model with a strong skin. As a viscous current spreads, it generates an isotropic strain rate tensor whose magnitude is independent of radius. Such a flow can account for the randomly oriented cracks that are uniformly distributed on the surface of the domes. The stress induced by the flow in the plains material below is obtained, and is probably large enough to produce the short radial cracks in the surface of the plains beyond the domes. The viscosity of the domes can be estimated from their thermal time constants if spreading is possible only when the fluid is hot, and lies between 10(exp 14) and 10(exp 17) Pa s. Laboratory experiments show that such viscosities correspond to temperatures of 610 - 690 C in dry rhyolitic magmas. These temperatures agree with laboratory measurements of the solidus temperature of wet rhyolite. These results show that the development of the domes can be understood using simple fluid dynamical ideas, and that the magmas involved can be produced by wet melting at depths below 10 km, followed by eruption and degassing.

Mckenzie, Dan↗