General Dusty Gas Model for porous media with a specified pore size distribution

Abstract

The standard Dusty Gas Model (DGM) for multicomponent diffusion in a porous medium assumes a single pore size in the domain. It is more appropriate to consider a distribution of pore sizes, which is addressed in this article. It derives a general form for the DGM that accounts for any pore size distribution of the porous medium. A few numerical examples demonstrate the strength of the general model. It predicts different diffusive behaviors for diverse pore size distributions possessing the same mean size. Specifically, the bimodal nature of the distribution exhibits a greater effect. The article further elucidates on the effects of the temperature and the pore size dependent variable tortuosity. All the phenomena are backed by physical arguments. The article concludes by recognizing the need for new targeted experiments for further validation.