Simulation of surface deposition of colloidal spheres under flow

The deposition kinetics of stable colloidal spheres from dilute dispersions flowing through a model pore in the high surface coverage range has been investigated. After deposition of each particle, the new flow field is calculated by using a flow simulator that solves the Navier–Stokes equations. The results provide both the surface coverage Γ and the hydrodynamic thickness δh of deposited layer as a function of a “hydrodynamic shadowing” Péclet number Pehs, which has been defined to be relevant for this process. A first result is that for Pehs≤1, both the surface coverage Γ and the equivalent hydrodynamic thickness of deposited layer show a definite plateau. In this regime, the plateau value of Γ at high surface coverage as well as deposition kinetics are identical to those given by the random sequential adsorption theory (RSA). A second result is that for Pehs≥1 both Γ and δh are decreasing function of flow strength. In addition, although limited simulations have been carried out in that regime, the surface coverage seem to decrease as Pehs−1/3, in agreement with both a theoretical approach based on diffusion layer approximation and previous experimental results. This good agreement suggests that the numerical simulation approach described in this paper is valid so that, it could be used to investigate multi-layer deposition and the corresponding porous media permeability damage by introducing an attractive particle–particle potential.