| Popis: |
We have used a highly reduced gravity environment to remove the masking influence of normal gravity and examine capillary flow in porous media by combining experiments from high altitude parabolic aircraft flights and from the STS-91 space shuttle flight, with simulations performed using a simple finite-difference numerical model. These studies involved a range of gravitational accelerations, surface tensions, viscosities, wetting preferences, permeabilities, and pore radii on capillary flow. Throughout enhanced to terrestrial to highly reduced gravitational accelerations, bead-pack experiments and numerical simulation results provided quite good agreement when the constraining cell walls were not preferentially wetted by the liquid. When the walls were wetted by the liquid the simulations provided severe underestimates of the experimental capillary flow results, apparently due to pronounced fluid flow along the inner cell walls under highly reduced gravity conditions. For sand-pack 1g experiments the numerical simulations provided reasonable predictions; for nearzero gravity experiments some simulations provided |
