ESTIMATION OF EFFECTIVE TRANSPORT-COEFFICIENTS IN POROUS SOLIDS BASED ON PERCOLATION CONCEPTS

Present available means to predict mass transport of gases in porous solids are inaccurate as a consequence of the inherent difficulties encountered in properly relating the local transport coefficients to the highly complex pore space. Within the concepts of percolation theory the authors make use of a network model of pore topology, a Bethe lattice, to simulate pore space related properties in porous solids. This network allows an exact evaluation of effective transport coefficients for binary mixtures, without resorting to tortuosity factors. In addition, it fundamentally accounts for the influences of narrow necks, tortuous paths and dead ends. A general form of the 'dusty gas' model is used to describe transport at a pore level. The method is simple to use and model predictions are in good agreement with published experimental data.