Multiscale simulation of colloids ingressing porous layers with evolving internal structure

Abstract

We report on a reaction-diffusion model posed on multiple spatial scales that accounts for diffusion, aggregation, fragmentation, and deposition of populations of colloidal particles. The model is able to account for the heterogeneity of the internal porous structure of the layer. For simplicity, we represent the microstructures as discs with prescribed initial random distribution of radii. As microstructures grow due to the deposition of populations of colloidal particles, local clogging becomes possible, that is neighbouring disks may touch each other. We investigate how distributions of evolving microstructures influence the transport and storage properties of porous layers. As working tool, we propose a FD-FEM discretization of the multiscale model. We illustrate numerically local clogging effects on the dispersion tensor and quantify herewith the layer’s performance with respect to both the efficiency of the transport and the storage capacity. The presented model and numerical approach can be extended in a rather straightforward way to handle slightly more complex geometrical settings like thin porous structures with multi-layers in 2D, or single layers in 3D.