Dispersion in Porous Media for Multicomponent Systems
Michel Quintard1, Laurent Bletzacker1, Damien Chenu1, and Stephen Whitaker2. (1) Institut de Mécanique des Fluides, allee C. Soula, Toulouse, 31400, France, (2) Chemical Engineering and Material Sciences, University of California, Davis, 3014 Brainer Hall, Davis, CA 95616
In this paper we consider multicomponent mass transport in porous media for non-dilute solutions, i.e., with full diffusion matrices. This process is described by coupled, nonlinear transport equations that must be spatially smoothed in order to be useful. This spatial smoothing is achieved by the method of volume averaging for the case of negligible adsorption, desorption, and heterogeneous reaction. For pure diffusion, the results demonstrate that a single tortuosity tensor applies to the transport of all species. When convective transport is important, the process becomes much more complex. A generalized dispersion theory is proposed. The results show that some simplifications may be introduced in the linear dispersion case only.