Heat and mass transfer in a porous material with an allowance for the relaxation (process) of the mass flux

The model of heat and mass transfer is viewed in a porous body with two types of pores suitable for the description of the initial stage of the penetration of the substance in a porous system (or the reverse process — extracting material out of it). The relaxation of the diffusion flux is taken into account in large channels. A solution of the task with typical in practice additional conditions was received at which were found the kinetic function of impregnation (extraction) of the porous medium and the flux density of the substance out of the body.