THEORETICAL-STUDY OF INTERPHASE HEAT AND MASS-TRANSFER IN SATURATED POROUS-MEDIA

Transient convective heat and mass transfer between the solid and flui d phases of a saturated porous medium has been considered in the prese nt study. A geometrically simple model that is capable of predicting r etardation 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 spec ies concentration in the liquid phase is determined by analytically so lving the system of differential equations along with experimentally m otivated values of the interphase parameter. The following problems ha ve been separately considered: (1) transient heat transfer between a h eated fluid and an initially cold matrix; (2) mass transfer of a radio active nuclide from a contaminated matrix into a clean fluid; (3) tran sport of a radioactive nuclide present in a fluid flowing through an i nitially clean matrix; (4) effect of a non-zero dispersion length. Res ults show that interphase transport between the solid and fluid is an important factor in retarding species transport in the porous region a s a whole. Equilibrium in species concentration between the two phases is seen to be attained only under special conditions. Copyright (C) 1 997 Elsevier Science Ltd.