FLUID CONFIGURATIONS IN PARTIALLY SATURATED POROUS-MEDIA

Two model porous media and a precise drying protocol are employed in numerical simulation of fluid configurations in partially saturated porous media. Particular attention is given to the behavior of pore fluid configurations as the vapor network invades the pore space. Over a substantial range of partial saturation N(L), the fluid configurations are inhomogeneous on a length scale that is a sensitive function of N(L). At low partial saturations, the fluid configurations are probabilistically disordered. Several measures of the characteristics of fluid configurations are developed. The partial saturation as a function of the chemical potential (i.e., the radius of the smallest vapor filled pore) gives a global description of the drying process. Details of the fluid configurations are found in the study of p (x; l,N(L)), the probability density for a porous medium of partial saturation N(L) to contain a piece of material of size l(d) having partial saturation x. This probability density is a gauge of inhomogeneity and appears importantly in NMR studies of porous media.