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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 865 records · Page 48
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NASA NTRS1972

Purification of contaminated water by filtration through porous glass

Method for purifying water that is contaminated with mineral salts and soluble organic compounds is described. Method consists of high pressure filtration of contaminated water through stabilized porous glass membranes. Procedure for conducting filtration is described. Types of materials by percentage amounts removed from the water are identified.

Wydeven, T.↗
NASA NTRS1969

Two phase flow and heat transfer in porous beds under variable body forces, part 2

Analytical and experimental investigations of a pilot model of a channel for the study of two-phase flow under low or zero gravity are presented. The formulation of dimensionless parameters to indicate the relative magnitude of the effects of capillarity, gravity, pressure gradient, viscosity, and inertia is described. The investigation is based on the principal equations of fluid mechanics and thermodynamics. Techniques were investigated by using a laser velocimeter for measuring point velocities of the fluid within the porous material without disturbing the flow.

Evers, J. L.↗
NASA NTRS1972

Analysis of heat transfer in a porous cooled wall with variable pressure and temperature along the coolant exit boundary

Fluid from a reservior at constant pressure and temperature is forced through a porous wall of uniform thickness. The boundary through which the fluid exits has specified variations in pressure and temperature along it in one direction so that the flow and heat transfer are two-dimensional. The local fluid and matrix temperatures are assumed to be equal and therefore a single energy equation governs the temperature distribution within the wall. The solution is obtained by transforming this energy equation into potential plane coordinates, which results in a separable equation. A technique yielding an integral equation is used to adapt the general solution so that it satisfies the variable-pressure boundary condition. Analytical expressions are given for the normal exit velocity and heat flux along the exit boundary. Illustrative examples are carried out which indicate to what extent the solution is locally one-dimensional.

Siegel, R.↗
NASA NTRS1972

Influence of porous-wall thermal effectiveness on turbulent-boundary-layer heat transfer

In view of the interest in employing porous wall materials for which the wall thermal effectiveness is less than unity, the influence of the effectiveness on the convective heat-transfer coefficient is examined. A Couette-flow model of the turbulent boundary layer shows that the familiar expression for the Stanton number with mass transfer at the boundary is modified by a correction factor that accounts for the wall thermal effectiveness and the effectiveness of the film layer in protecting the surface from the hot gas stream. The correction term is found be of considerable importance for low values of blowing rate and wall thermal effectiveness.

Lecuyer, M. R.↗
NASA NTRS1972

Lunar soil properties and soil mechanics. Flow in porous media under rarefied gas conditions. Research phase: Fluid conductivity of lunar surface materials

Theoretical and experimental research on fluid conductivity of lunar surface materials is summarized. Theoretical methods were developed for the analysis of transitional and free-molecular flows, and for analysis of lunar permeability probe data in general. Experimental studies of rarefied flows under conditions of a large pressure gradient show flows in the continuum regime to be responsible for the largest portion of the pressure drop between source and sink for one dimensional flow, provided the entrance Knudsen number is sufficiently small. The concept of local similarity leading to a universal nondimensional function of Knudsen number was shown to have approximate validity; flows in all regimes may be described in terms of an area fraction and a single length parameter. Synthetic porous media prepared from glass beads exhibited flow behavior similar in many regards to that of a natural sandstone; studies using artificial stones with known pore configurations may lead to new insight concerning the structure of natural materials. The experimental method involving the use of segmented specimens of large permeability is shown to be fruitful.

Hurlbut, F. C.↗