Synergy of Injection Velocity, Hypergravity, and Porous Medium Skeleton for Particle Migration and Distribution Characteristics: Insights from CFD-DEM Investigations

Hypergravity experimentation is an effective approach to model field-scale particle migration issues at meter scale, such as internal erosion. However, the unclear migration and distribution characteristics of particles, which is caused by monitoring technology and medium opacity, limit the accuracy of hypergravity experiments and the establishment of scaling law. A series of coupled computational fluid dynamic and discrete element method (CFD-DEM) simulations were conducted to clarify these characteristics of particles at pore scale in the case where the directions of the fluid injection velocity and hypergravity were perpendicular. The synergy of injection velocity, hypergravity, and porous medium skeleton induced the deflection of particle migration path and the transition of particle distribution pattern from uniform to concentrated. The deflection angle of particle migration path in a water tank without porous medium skeleton (θdw) was determined by the ratio of Ar and Rep. In porous medium, benchmarked by θdw, the obstruction of porous medium disturbed particles migration path by a factor of 0.84 at θdw<20°. At 20°<θdw<60°, porous medium binned particle migration path deflection angle at 31° or 56°, which are the first and the second tangential directions across two adjacent columns of micropillars. At θdw>60°, hypergravity dominated, and particle trajectory was akin to that in a water tank with a factor of 0.97. Scaling effects of hypergravity on particle velocity were preserved to a large extent at θdw≤5.1°, and were disturbed at θdw>5.1°, but could be calibrated via numerical simulation. These results provide guidance for hypergravity experiments in the selection of operating conditions, establishment of similarity criteria, and prediction of particle migration and distribution.