Coupled DEM-CFD Model to Predict the Tumbling Mill Dynamics

Abstract

The charge motion in a tumbling mill has been mostly described by empirical, mechanistic and computational models. The computational model presented in this work is a three phase approach for the tumbling mill that combines a particle description for the solids modelled by the Discrete Element Method, and the continuum description for the fluid by CFD approach. In the present work a phase coupled approach is developed using C++ subroutines to model the charge and slurry dynamics inside a tumbling mill by mapping the particles on the CFD mesh and resolving the particle volume and velocities on per cell basis. The coupled DEM-CFD approach is implemented and the effect of drag force on the slurry by the particle motion. The set of coupled simulation were run varying the slurry rheology and results were validated with equivalent PEPT experiment of lab scale mills and a very good agreement is found in some cases. The Beeststra drag correlation was used to calculate the drag force between the fluid and the particles. The free surface profile of the charge as well as the slurry is calculated as well as the axial center of mass profile of the mill.