SEARCH · Engineering Papers

Results for “Fluid System”

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.

SourceResearch connectionFrom yearThrough year

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

At least 1,027 records · Page 57

All sources NASA NTRS DOE OSTI

NASA NTRS1979

Calculated global conditions for the unsteady Euler's flow equations

This paper considers the numerical solution of a fluid dynamical system with time-dependent oscillating boundaries. The problem detailed, a compressible and inviscid flow in a one-dimensional pipe with vibrating ends, is examined to develop techniques needed to solve the more complex unsteady flows in turbomachine cascades. The problem is shown to be mathematically ill-posed but by complementing the governing equations with energy conservation, a unique solution is obtained. An artificial damping term is introduced into the governing equations to improve the performance of the time-marching integration.

Kuzo, D. M.↗

NASA NTRS1980

A fan pressure ratio correlation in terms of Mach number and Reynolds number for the Langley 0.3 meter transonic cryogenic tunnel

Calibration data for the two dimensional test section of the Langley 0.3 Meter Transonic Cryogenic Tunnel were used to develop a Mach number-Reynolds number correlation for the fan pressure ratio in terms of test section conditions. Well established engineering relationships combined to form an equation which is functionally analogous to the correlation. A geometric loss coefficient which is independent of Reynolds number or Mach number was determined. Present and anticipated uses of this concept include improvement of tunnel control schemes, comparison of efficiencies for operationally similar wind tunnels, prediction of tunnel test conditions and associated energy usage, and determination of Reynolds number scaling laws for similar fluid flow systems.

Lawing, P. L.↗

NASA NTRS1983

Tapped-Hole Vent Path

Long helical vent path cools and releases hot pyrotechnical gas that exits along its spiraling threads. Current design uses 1/4-28 threads with outer diameter of stud reduced by 0.025 in. (0.62 mm). To open or close gassampler bottle, pyrotechnic charges on either one side or other of valve cylinder are actuated. Gases vented slowly over long path are cool enough to present no ignition hazard. Vent used to meter flow in refrigeration, pneumaticcontrol, and fluid-control systems by appropriately adjusting size and length of vent path.

Chandler, J. A.↗

NASA NTRS1982

A general method to determine the stability of compressible flows

Several problems were studied using two completely different approaches. The initial method was to use the standard linearized perturbation theory by finding the value of the individual small disturbance quantities based on the equations of motion. These were serially eliminated from the equations of motion to derive a single equation that governs the stability of fluid dynamic system. These equations could not be reduced unless the steady state variable depends only on one coordinate. The stability equation based on one dependent variable was found and was examined to determine the stability of a compressible swirling jet. The second method applied a Lagrangian approach to the problem. Since the equations developed were based on different assumptions, the condition of stability was compared only for the Rayleigh problem of a swirling flow, both examples reduce to the Rayleigh criterion. This technique allows including the viscous shear terms which is not possible in the first method. The same problem was then examined to see what effect shear has on stability.

Guenther, R. A.↗

NASA NTRS1979

Crystal growth of sulfide materials from alkali polysulfide liquids

The fluids experiment system was designed for low temperature solution growth, nominally aqueous solution growth. The alkali polysulfides, compositions in the systems Na2S-S and K2S-S form liquids in the temperature range of 190 C to 400 C. These can be used as solvents for other important classes of materials such as transition metal and other sulfides which are not soluble in aqueous media. Among these materials are luminescent and electroluminescent crystals whose physical properties are sensitive functions of crystal perfection and which could, therefore, serve as test materials for perfection improvement under microgravity conditions.

White, W. B.↗

NASA NTRS1982

Solution growth of crystals in zero gravity

A series of experiments will be performed in which triglycine sulfate (TGS) crystals will be grown by a low-temperature solution growth technique in the microgravity environment of the orbital Spacelab. Triglycine sulfate (TGS) crystals will be grown in the Fluid Experiment System (FES) facility on Spacelab 3 by slowly extracting heat at a controlled rate through a seed crystal of TGS suspended on an insulated sting in a saturated solution of TGS. The FES rack assembly designed for SL-3 is shown in Figure I-1, and a detailed view of the test cell layout is presented in Figure I-2. Variations in the liquid density, solution concentration and temperature around the growing crystal will be studied using a variety of techniques, such as schlieren, shadowgraph, and interferometric measurements. Growth in Earth gravity will also be studied by the same optical techniques, and in both cases the resulting crystalline features will be compared and correlated with the growth conditions.

Lai, R. B.↗

NASA NTRS1985

High pressure cosmochemistry applied to major planetary interiors: Experimental studies

The measurement of equilibria in binary fluid-solid systems in diamond anvil cells, represents a major advance of the art of high-pressure experimentation. Vibrational spectroscopy, direct visual observations, and X-ray diffraction crystallography of materials confined in externally heated cells are the primary experimental probes being used. Adiabats in these systems are being measured in order to constrain models of heat flow in these bodies and to detect phase transitions by thermal anomalies. Other studies are directed toward interpreting high pressure reactions in these systems that are suggested by shockwave measurements, and developing methods for reaching high temperatures and high pressures of planetary interest in diamond cells. The overall objective of this project is to determine the properties of the H2-He-H2O-HN3-CH4 system and related small-molecule systems that are needed to constrain theoretical models of the interiors of the major planets.

Nicol, M. F.↗

NASA NTRS1985

Solution Growth of Crystals in Zero-Gravity

In a low-g environment, buoyancy driven convection effects in solution crystal growth are greatly reduced and, thus, one can study diffusion mass transport which in 1-g is masked by convective phenomena. Crystals of triglycine sulfate (TGS) will be grown aboard the Spacelab 3 mission, using a specially developed Fluids Experiments System (FES). The objectives of the experiment are: (1) to develop a technique for solution crystal growth in a low-g environment, (2) to characterize the growth environment provided by an orbiting spacecraft and to determine the influence of the environment on the growth behavior, and (3) to determine how gravity in a low-gravity environment influences the properties of a resulting TGS crystal. Single crystals of TGS have been grown using conventional low-temperature solution crystal growth method and the growth process has been extensively characterized. Various physical properties of TGS solution have been measured. Also, a unique technique of growing solution growth crystals by extracting heat at a programmed rate from the crystal through a semi-insulating sting has been developed and tested in 1-g environment.

Lal, R. B.↗

NASA NTRS1985

Thermocapillary Flows and Their Stability: Effects of Surface Layers and Contamination

The objective is to study quantitatively thermocapillary flows in two-dimensional and axisymmetric geometries in order to learn the impact of such flows on float-zone refining configurations. The work begins with the analytical study of steady flows in slots and zones to obtain predictions of surface curvature, flow and heat transport. It then examines the instability of such flows. Three new instability mechanisms have been identified and the results show that thermocapillary flows of high Prandtl number fluid become convectively unstable while those of low Prandtl number fluid become hydrodynamically unstable. The work includes numerical simulations of steady, high Marangoni number flows in unit aspect ratio boxes and asymptotic solutions in large boxes. Furthermore, the effect of surface contamination on the steady thermocapillary flows was examined. This fundamental study focused on fluid dynamical systems used to understand events in the flow of melts in float-zone geometries both on Earth and in microgravity environments.

Davis, S. H.↗

NASA NTRS1985

Space station advanced propulsion and fluid management program

In preparation for the development of a manned space station program of advanced technology and development to make new advanced propulsion options available for the initial space station in the 1990's is described. This paper reviews the objectives of the advanced technology and development program in propulsion, describes its origin and how it relates to the forthcoming development program. The advanced propulsion and fluid management systems to be investigated in the program are discussed along with the rationale for their selection. Finally, the systems test program is discussed.

Richmond, R. J.↗

NASA NTRS1984

Space Processing Workshop

Gravitational effects on electrodeposition were studied on the KC-135 aircraft parabolic flight paths. An experiment to investigate the effect of the hyperthermal atomic oxygen atmosphere on sensitive surfaces was flown on Space Shuttle Flight STS-18. A participant list and schedule for the Fluids Experiment System (FES) Workshop are given.

Source record↗

NASA NTRS1987

Reconstruction techniques of holograms from Spacelab 3

Fluid transport effects in a ground-based laboratory are fairly well known. Bouyancy driven transport occurs when there is a local density change in the fluid. In a low-g environment these density changes become less important, and other transport mechanisms dominate. To better understand fluid flows in a low-g environment, a fluid experiment system (FES) was designed to fly aboard the Shuttle orbiter in Spacelab. The FES is a holographic system designed for acquisition of the maximum amount of data from an experiment. The FES flew for the first time in May 1985 on Spacelab 3 for investigation of triglycine sulfate (TGS) crystal growth in low-g. This paper describes the FES optical system. The reconstruction techniques of the holograms are examined in detail, and the multiuser and reflight capabilities are discussed. Proposed future experiments are mentioned.

Witherow, William K.↗

NASA NTRS1987

Ames Research Center cryogenics program

Viewgraphs describe the Ames Research Center's cryogenics program. Diagrams are given of a fluid management system, a centrifugal pump, a flow meter, a liquid helium test facility, an extra-vehicular activity coupler concept, a dewar support with passive orbital disconnect, a pulse tube refrigerator, a dilution refrigerator, and an adiabatic demagnetization cooler.

Kittel, Peter↗

NASA NTRS1985

Holography on the Spacelab 3 mission

Spacelab 3's Fluid Experiment System, in which triglycine sulfate crystals were produced by a low temperature solution-growth technique, employs holography as its primary data-gathering system. This use of holography allows optical techniques which would be difficult to apply in orbit to be used after the holographic data is returned to ground laboratories, using an analysis of the reconstructed holographic image. The system used allows both single- and double-exposure holograms to be obtained in two separate orthogonal configurations.

Owen, Robert B.↗

NASA NTRS1988

Venus' superrotation, mixing length theory and eddy diffusion - A parametric study

The concept of the Hadley mechanism is adopted to describe the axisymmetric circulation of the Venus atmosphere. It is shown that, for the atmosphere of a slowly rotating planet such as Venus, a form of the nonliner 'closure' (self-consistent solution) of the fluid dynamics system which constrains the magnitude of the eddy diffusion coefficients can be postulated. A nonlinear one-layer spectral model of the zonally symmetric circulation was then used to establish the relationship between the heat source, the meridional circulation, and the eddy diffusion coefficients, yielding large zonal velocities. Computer experiments indicated that proportional changes in the heat source and eddy diffusion coefficients do not significantly change the zonal velocities. It was also found that, for large eddy diffusion coefficients, the meridional velocity is virtually constant; below a threshold in the diffusion rate, the meridional velocity decreases; and, for large eddy diffusion and small heating rates, the zonal velocities decrease with decreasing planetary rotation rates.

Mayr, H. G.↗

NASA NTRS1989

Fluid/electrolyte and endocrine changes in space flight

The primary effects of space flight that influence the endocrine system and fluid and electrolyte regulation are the reduction of hydrostatic gradients, reduction in use and gravitational loading of bone and muscle, and stress. Each of these sets into motion a series of responses that culminates in alteration of some homeostatic set points for the environment of space. Set point alterations are believed to include decreases in venous pressure; red blood cell mass; total body water; plasma volume; and serum sodium, chloride, potassium, and osmolality. Serum calcium and phosphate increase. Hormones such as erythropoietin, atrial natriuretic peptide, aldosterone, cortisol, antidiuretic hormone, and growth hormone are involved in the dynamic processes that bring about the new set points. The inappropriateness of microgravity set points for 1-G conditions contributes to astronaut postflight responses.

Huntoon, Carolyn Leach↗

NASA NTRS1989

Modeling of turbulence for compression corner flows and internal flows

A compressible Reynolds averaged Navier-Stokes code is applied to examine the performances of basic turbulence models for unseparated and separated flows. The turbulence models considered are a zero-equation model and several two-equation models, including a new k-epsilon model with an eddy viscosity damping function depending upon the Reynolds number and the distance from the wall. The turbulence models are assessed using the following experimental flows: a channel flow, a backward facing step, and a two-dimensional compression corner at Mach 2.8. Discussions and comparisons of the experimental and numerical results are given. Mesh refinement is shown to have a significant beneficial effect on free shear layer flow results obtained with two-equation turbulence models. The results illustrate the usefulness of several turbulence models as a design tool for fluid engineering systems.

Champney, J. M.↗

NASA NTRS1989

SSME LOX post flow analysis/fluid structure interaction. Volume 1: Flow analysis

The realization of measures to improve the performance of the Space Shuttle is, to a large extent, dependent on an improved understanding of the fluid flow phenomena occurring in the main engine. The overall arrangement of the primary components of the Space Shuttle Main Engine (SSME) are presented. The impingement of the hot gases from the transfer ducts onto the LOX posts causes them to be subjected to severe thermal and gas dynamic loads, which in the past have resulted in the occasional breakage of some elements of the outer row of posts during test firings of the engine, particularly at higher power levels. Large velocities in the gap between the LOX posts may also be a contributing factor in causing dynamic stability problems. The deforming structural response of the posts to the pressure loading may likely affect the gas flowfield by producing a moving flowfield boundary, thereby creating a dynamically coupled unsteady fluid-structure system. The objective was to investigate the three-dimensional, turbulent flow around a simplified SSME LOX post array using an existing Reynolds averaged Navier-Stokes flow solver and a suitable turbulence model to parameterize the turbulent shear stresses. Numerical computations were performed to analyze the effect on the flowfield of varying the spacing between the LOX posts, which were modeled as rigid, three-dimensional circular cylinders. The methodology used in the computations is described. Results are presented.

Burke, Roger W.↗