Influencing factors on fines deposition in porous media by CFD-DEM simulation

Evolution from fines migration to deposition and clogging is critical for many geotechnical and environmental engineering practices. In this study, the coupling of computational fluid dynamic and discrete element method was adopted to tackle fines migration. The surface energy density term c was used to represent the combination of Coulomb forces and van der Waals interactions. A particle-scale mechanical analysis method was adopted to identify three criteria of particle deposition conditions. (1) The drag force on the fines should be less than the electrical forces between particles, (2) the drag force and electrical force torques should be on the same order of magnitude, and (3) the contact angle between particles should be greater than 5.5 degrees. The deposition efficiency increases from 8.5 to 37.8% as surface density energy increases from 0.001 to 0.01 J/m(2) at a Reynolds number of 10. As the electrical force is more than 10 times the drag force, clogging occurred. Due to the inertial and Dean forces and the filtration effect of micropillars, a band of lacking particles appears in the symmetrical center of the pore throat.

Automated summary

The combination of computational fluid dynamic and discrete element method was used to study fines migration. Three criteria for particle deposition conditions were identified using a particle-scale mechanical analysis method. The results showed that the deposition efficiency increased from 8.5% to 37.8% as the surface energy density increased. Clogging occurred when the electrical force was more than ten times the drag force.