Mechanistic studies of capillary processes in porous media. Part 2.—Construction of porous networks by Monte-Carlo methods

Abstract

We reveal that present Monte-Carlo representations of porous networks are very unsatisfactory, since either (i) they are limited to the simulation of fully random networks corresponding to zero overlap between the site and the bond size distributions, a rather less frequent situation in natural and industrial materials, or (ii), in the more general case of overlapped distribution, they merely avoid any bond becoming bigger than any one of its two delimiting sites. In the case of a substantial degree of overlap it is absolutely necessary to observe the laws of self-consistency which were stated in Part 1 (J. Chem. Soc., Faraday Trans. I, 1989, 85, 2071). To disregard them would lead to (i) a certain departure of the size distributions of the resultant network, compared to those initially proposed and, much more importantly, (ii) an incapability to represent the morphology of topologically correlated structures (which play a major role in the characteristics of phase invasion and retraction during the course of capillary processes). A straightforward method for simulating porous media is proposed and its results, which agree with the considerations given in Part I are analysed, especially those dealing with (i) the size segregation arising as the overlap increases and (ii) the periodical properties of the network.