Theoretical study of interphase heat and mass transfer in saturated porous media

Abstract

Transient convective heat and mass transfer between the solid and fluid phases of a saturated porous medium has been considered in the present study. A geometrically simple model that is capable of predicting retardation of the species has been developed. The equations governing species transport in the liquid and solid phases of the porous medium are coupled due to heat and mass transfer at their interface. The species concentration in the liquid phase is determined by analytically solving the system of differential equations along with experimentally motivated values of the interphase parameter. The following problems have been separately considered: (1) transient heat transfer between a heated fluid and an initially cold matrix; (2) mass transfer of a radioactive nuclide from a contaminated matrix into a clean fluid; (3) transport of a radioactive nuclide present in a fluid flowing through an initially clean matrix; (4) effect of a non-zero dispersion length. Results show that interphase transport between the solid and fluid is an important factor in retarding species transport in the porous region as a whole. Equilibrium in species concentration between the two phases is seen to be attained only under special conditions.