Abstract
ions: a zone with mobile fluid (R⁺) and a zone with immobile fluid (R⁻). In the mobile region, the transport of suspended solid particles is considered with allowance for convection, longitudinal and transverse diffusion, as well as the evolution of porosity due to competing processes of colmation and suffusion. Fluid flow is described by a generalized Darcy’s law with a filtration coefficient dependent on porosity, including the Kozeny–Carman relationship, which makes it possible to relate the pressure field to spatially heterogeneous permeability. In region R⁻, mass transport is modeled by effective diffusion. A boundary-value problem with conjugate conditions at the interface and zero-flux conditions at distant boundaries is formulated. To solve the system of transport equations and porosity evolution, a finite-difference scheme on a nonstationary computational grid was developed and implemented in the Turbo Pascal environment; numerical experiments were performed for various values of D1, D2, D3, ω1, and ω2. The obtained distributions of relative concentration c/c0 demonstrate significant accumulation of matter in the immobile-fluid region and deformation of concentration surfaces near the interface between the regions. It is shown that the presence of an immobile-fluid zone and the inclusion of colmation-suffusion effects have a substantial impact on both the filtration characteristics of the medium and the nature of mass transport.