Pressure gradient hinders particle migration: An LBM-DEM study of clogging in irregular-shaped porous media

The migration of solid–liquid mixtures in porous media can be regarded as a complex coupling process that is frequently found in geotechnical engineering. Numerical methods are often used to investigate the complex mechanisms among particles, fluids, and porous media, and to explain their macroscopic interactions so that problems on an industrial scale can be solved. In recent years, there has been a growing tendency among researchers to turn to microscopic discrete element simulations to better understand the collective dynamics of individual particles in pore scales. In this study, the infiltration motion of slurry particles in an irregular-shaped porous medium generated by the Voronoi algorithm is investigated using the coupled scheme of the lattice-Boltzmann method (LBM) and the discrete element method (DEM). The infiltration dynamics of slurry particles in complex porous media were examined by varying the applied pressure and the porosity of the porous medium, based on which a non-monotonic pressure-response behaviour was identified. Results show that 40 kPa is the most favorable condition for deep penetration and reduced particle accumulation in the upper part of the medium, whereas the refined pressure series under the 45% retention-percentage condition shows that the highest final escaped fraction and escape efficiency occur at 70 kPa. In addition, increasing the retention percentage reduces the overall migration capacity and makes the high-pressure condition more prone to particle accumulation in the upper part of the medium. These results provide a micro-mechanical basis for understanding particle migration, retention, and clogging in irregular-shaped porous media, and offer guidance for engineering and industrial applications involving particle transport in porous systems.