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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 289 records · Page 16

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NASA NTRS1975

Results of investigation on an 0.015 scale configuration 140A/B space shuttle vehicle orbiter reaction control system plume-impingement model 36-0 in the NASA/Ames Research Center 3.5-foot hypersonic wind tunnel (0A83)

The results of aerodynamic pressure and wingroot bending-moment testing conducted on a 0.015-scale Configuration 140A/B space shuttle vehicle orbiter reaction control system plume-impingement model are documented. The model was investigated at nominal Mach numbers of 5.3, 7.3, and 10.3, at unit Reynolds numbers of 4,200,000 ft, 7,300,000 ft, and 1,700,000 ft. Model attitude was varied in angle of attack from 18 deg to 38 deg at angles of sideslip from -2 deg to +2 deg. The test program was conducted to establish and reaffirm incremental orbiter pressure-profile and structural-loads data due to operation of the aftbody reaction control system pitch-down engines.

Nicholas, M. E.↗

NASA NTRS1976

The small motor plume/material impingement test program at MSFC utilizing nine different propellant formulations (April and May 1974), section 2

The relative effects of several candidate SSRM propellant formulations and their plume impingement effects on HRSI and RCC materials were evaluated. Nine solid propellant formulations were tested. The selected propellant matrix allowed an evaluation of propellants with and without metal additives, with and without burning rate catalyst, and low (approximately 1927 C) and high (approximately 2649 C) combustion temperatures. Motors were fired at a simulated SRB staging altitude of 3.96 km (130,000 ft) (nominal). The altitude pressure was predicted to drop approximately 0.6 km (20,000 ft) during a motor firing. All motors were loaded with 1.8 to 2.3 kg (4 to 5 lb) of propellant and burned for approximately 2 s.

Source record↗

NASA NTRS1976

The oblique impingement of an axisymmetric jet

The mechanics of the oblique impingement of an axisymmetric jet on a plane surface are examined in detail. The stagnation point is discussed. A schematic drawing of the problem and coordinate system used to describe the flow field are given. The kinematic features of the flow above the plate are examined in the context of the conservation of mass, the vorticity of the jet, and the vorticity introduced by the jetplate interaction. The dynamic features of the flow are examined in terms of the surface pressure distribution and the cause-effect relationships which exist between the pressure and velocity/vorticity distributions. Flow calculations performed are given. The investigation is relevant to the flow resulting from the interaction of the propulsion jet with the main airfoil (STOL aircraft), and is appropriate to an over- or under- wing configuration.

Foss, J. F.↗

NASA NTRS1976

Liquid jet impingement normal to a disk in zero gravity

An experimental and analytical investigation was conducted to determine the free surface shapes of circular liquid jets impinging normal to sharp-edged disks under both normal and zero gravity conditions. An order of magnitude analysis was conducted indicating regions where viscous forces were not significant when computing free surface shapes. The demarcation between the viscous and inviscid region was found to depend upon the flow Reynolds number and the ratio between the jet and disk radius.

Labus, T. L.↗

NASA NTRS1977

Assessment of analytical techniques for predicting solid propellant exhaust plumes and plume impingement environments

An analysis of experimental nozzle, exhaust plume, and exhaust plume impingement data is presented. The data were obtained for subscale solid propellant motors with propellant Al loadings of 2, 10 and 15% exhausting to simulated altitudes of 50,000, 100,000 and 112,000 ft. Analytical predictions were made using a fully coupled two-phase method of characteristics numerical solution and a technique for defining thermal and pressure environments experienced by bodies immersed in two-phase exhaust plumes.

Tevepaugh, J. A.↗

NASA NTRS1977

Liquid jet impingement normal to a disk in zero gravity

The free surface shapes of circular liquid jets impinging normal to sharp-edged disks in zero gravity are determined. Zero gravity drop tower experiments yielded three distinct flow patterns that were classified in terms of the relative effects of surface tension and inertial forces. An order of magnitude analysis was conducted that indicated regions where viscous forces were not significant in the computation of free surface shapes. The free surface analysis was simplified by transforming the governing potential flow equations and boundary conditions into the inverse plane, where the stream function and velocity potential became the coordinates. The resulting nonlinear equations were solved by standard finite difference methods, and comparisons were made with the experimental data for the inertia dominated regime.

Labus, T. L.↗

NASA NTRS1977

Modelling techniques for jet impingement

A technique for testing scale models for the determination of fluctuating pressure loads due to jet impingement has been investigated using a quarter-scale model of a boilerplate test facility in which a JT-15D engine with a rectangular outer nozzle blows over a small curved airfoil representing the upper-surface of a wing. When model and full-scale spectra of fluctuating surface pressures are reduced to plots of pressure coefficient power-spectral density vs Strouhal number, moderate agreement is obtained, but a shift of spectral peaks is noted. However, when a correction for the ratio of average jet to ambient temperature is applied, the spectral peaks agree.

Haviland, J. K.↗

NASA NTRS1978

A computer program for the transient thermal analysis of an impingement cooled turbine blade

A computer program to calculate transient and steady state temperatures, pressures, and coolant flows in a cooled turbine blade or vane with an impingement insert is described. Input to the program includes a description of the blade geometry, coolant supply conditions, outside thermal boundary conditions and wheel speed. Coolant-side heat transfer coefficients are calculated internally in the program, with the user specifying the mode of heat transfer at each internal flow station. Program output includes the temperature at each node, the coolant pressures and flow rates, and the inside heat transfer coefficients. A sample problem is discussed.

Gaugler, R. E.↗

NASA NTRS1978

Application of the Bernoulli enthalpy concept to the study of vortex noise and jet impingement noise

A complete theory of aeroacoustics of homentropic fluid media is developed and compared with previous theories. The theory is applied to study the interaction of sound with vortex flows, for the DC-9 in a standard take-off configuration. The maximum engine-wake interference noise is estimated to be 3 or 4 db in the ground plane. It is shown that the noise produced by a corotating vortex pair departs significantly from the compact M scaling law for eddy Mach numbers (M) greater than 0.1. An estimate of jet impingement noise is given that is in qualitative agreement with experimental results. The increased noise results primarily from the nonuniform acceleration of turbulent eddies through the stagnation point flow. It is shown that the corotating vortex pair can be excited or de-excited by an externally applied sound field. The model is used to qualitatively explain experimental results on excited jets.

Yates, J. E.↗

NASA NTRS1976

Investigations of scaling laws for jet impingement

The statistical properties of tangential flows over surfaces were investigated by two techniques. In one, a laser-Doppler velocimeter was used in a smoke-laden jet to measure one-point statistical properties, including mean velocities, turbulent intensities, intermittencies, autocorrelations, and power spectral densities. In the other technique, free stream and surface pressure probes connected to 1/8 inch microphones were used to obtain single point rms and 1/3 octave pressures, as well as two point cross correlations, the latter being converted to auto spectra, amplitude ratios, phase lags, and coherences. The results of these studies support the vortex model of jets, give some insights into the effects of surface impingement, and confirm that jet diameter and velocity are the scaling parameters for circular jets, while Reynolds number is relatively unimportant.

Morton, J. B.↗

NASA NTRS1978

A computer program for the transient thermal analysis of an impingement cooled turbine blade

Gaugler, R. E.↗

NASA NTRS1978

Liquid jet impingement normal to a disk in zero gravity

An experimental and analytical investigation was conducted to determine the free surface shapes of circular jets impinging normal to sharp-edged disks in zero gravity. Experiments conducted in a zero gravity drop tower yielded three distinct flow patterns which were classified in terms of the relative effects of surface tension and inertial forces. An order of magnitude analysis was conducted indicating regions where viscous forces were not significant when computing free surface shapes. The free surface analysis was simplified by transforming the governing potential flow equations and boundary conditions into the inverse plane. The resulting nonlinear equations were solved numerically and comparisons were made with the experimental data for the inertia dominated regime.

Labus, T. L.↗

NASA NTRS1978

Numerical solution of two-dimensional turbulent blunt body flows with an impinging shock

An implicit finite-difference method has been developed to compute two-dimensional, turbulent, blunt body flows with an impinging shock wave. The full time-averaged Navier-Stokes equations are solved with algebraic eddy viscosity and turbulent Prandtl number models employed for shear stress and heat flux. The irregular-shaped bow shock is treated as a discontinuity across which the Rankine-Hugoniot equations are applied. A Type III turbulent shock interference flow field has been computed and the numerical results compare favorably with existing experimental data. In addition, comparisons are made between the present implicit code and a previous explicit code.

Tannehill, J. C.↗

NASA NTRS1979

Photographic observation of reactive stream impingement

The theoretical and experimental study described was carried out to gain insight into the physical-chemical mechanism which controls hypergolic propellant reactive stream separation (RSS), with a view toward establishing design criteria. The approach employed was to observe photographically single element injector combustion of N2O4/MMH, N2O4/A-50, and N2O4/N2H4 propellants. Single element injectors were used to provide an unobstructed view of the impingement zone. Hot firings were conducted in a special photographic chamber. High-speed color motion pictures were used to identify the occurrence of RSS. Four conventional unlike doublet injectors, two conventional triplet injectors, and three platelet injectors were used in the tests. A simulation of the Space Shuttle platelet injector was included. The most important design criterion derived from the study states that the element should be designed to avoid transitions between mixed and separated modes within the engine operational envelope.

Lawver, B. R.↗

NASA NTRS1980

Multiple jet impingement heat transfer characteristic: Experimental investigation of in-line and staggered arrays with crossflow

Heat transfer characteristics were obtained for configurations designed to model the impingement cooled midchord region of air cooled gas turbine airfoils. The configurations tested were inline and staggered two-dimensional arrays of circular jets with ten spanwise rows of holes. The cooling air was constrained to exit in the chordwise direction along the channel formed by the jet orifice plate and the heat transfer surface. Tests were run for chordwise jet hole spacings of five, ten, and fifteen hole diameters; spanwise spacings of four, six, and eight diameters; and channel heights of one, two, three, and six diameters. Mean jet Reynolds numbers ranged from 5000 to 50,000. The thermal boundary condition at the heat transfer test surface was isothermal. Tests were run for sets of geometrically similar configurations of different sizes. Mean and chordwise resolved Nusselt numbers were determined utilizing a specially constructed test surface which was segmented in the chordwise direction.

Florschuetz, L. W.↗

NASA NTRS1981

A summary of jet-impingement studies at McDonnell Douglas Research Laboratories

It has been the primary objective of the considered studies to determine and describe, through calculation, measurement, and visualization of the flowfields, the basic character of isolated and interacting impinging jets. The secondary objective has been to provide computed and experimental flow properties which can be used in the development and verification of empirically based prediction methodologies for complete aircraft configurations. The studies have resulted in the solution of the Reynolds-averaged Navier-Stokes and Jones-Launder turbulence model equations for two- and three-dimensional configurations and in the acquisition of an extensive data base and flow-visualization photographs for these configurations.

Bower, W. W.↗

NASA NTRS1982

Universal approach to analysis of cavitation and liquid-impingement erosion data

Cavitation erosion experimental data was analyzed by using normalization and curve-fitting techniques. Data were taken from experiments on several materials tested in both a rotating disk device and a magnetostriction apparatus. Cumulative average volume loss rate and time data were normalized relative to the peak erosion rate and the time to peak erosion rate, respectively. From this process a universal approach was derived that can include data on specific materials from different test devices for liquid impingement and cavitation erosion studies.

Rao, P. V.↗

NASA NTRS1983

A comprehensive analysis of cavitation and liquid impingement erosion data

Cavitation-erosion experimental data previously covering several materials tested in a rotating disk device and a magnetostriction apparatus were analyzed using new normalization and curve-fitting techniques. From this process a universal approach is derived which can include data from cavitation and liquid impingement studies for specific materials from different test devices.

Rao, P. V.↗