Динамика частиц в пористой среде
When designing tunnels and underground structures, filtration of particles in porous rock has to be
considered. Long-term, deep bed filtration of suspensions and colloids in a porous medium leads to the formation of
deposit in the pores and a change in the structure of the porous rock framework. The filtration model includes the
equation for the balance of the suspended and deposited particles concentrations and the kinetic equation for the
deposit growth. The filtration process is determined by the filtration function, which sets the dependence of the deposit growth rate on the retained particles concentration. The type of filtration function depends on the properties of particles, carrier-fluid and porous media. The dynamics (time dependence) of the suspended and deposited particles concentrations is studied for various filtration functions at the point of particles exit from a porous medium. It is shown that at large time intervals the growth rate of both concentrations decreases and tends to zero. For a short time interval, the growth rates of sediment concentration decrease for small particles and increase for large particles, the growth rates of suspended particle concentration increase or decrease depending on the type of filtration function. The conditions for the existence of inflection points on the graphs of the concentration dynamics at the porous medium outlet are obtained.