A two-phase mixture model of liquid-gas flow and heat transfer in capillary porous media-I. Formulation

A model for two-phase transport in capillary porous media is presented, in which the two phases are viewed as constituents of a binary mixture. The conservation equations are derived from the classical separate flow model without invoking additional assumptions. The present formulation, owing to its analogy to conventional multicomponent mixture flow theories and to a considerable reduction in the number of the differential equations required for the primary variables, provides an alternative for the theoretical analysis and numerical simulation of two-phase transport phenomena in porous media. Several complicated problems such as boundary layer two-phase flows, conjugate two- and single-phase flows in multiple regions and transient flows are shown to become more tractable within the framework of this new formulation.