A coupled CFD–DEM model for tumbling mill dynamics—Effect of lifter profile

Abstract

In comminution circuits, grinding is the most energy-intensive process. Although significant work was focused on the charge particle dynamics via only DEM in the past, but lifter effects and slurry viscosity have often been overlooked. This work aims to develop a coupled CFD–DEM model to precisely predict mill dynamics involving slurry, charge, and air as free surface. The model uses the VOF method for the slurry–air interface and DEM for charge motion, connecting them through momentum exchange. Suitable slurry rheology and viscous drag sub-models are incorporated. Tumbling mill slurry and charge dynamics are simulated for varied lifter profiles, mill speeds, and slurry pulp conditions. Coupled CFD–DEM and only DEM models are validated against slurry-based Positron Emission Particle Tracking (PEPT) based data. Further, this coupled model is used to assess the effect of lifter face angles and slurry wt% solids on charge dynamics in terms of the mill’s power consumption and the kinetic energy spectra.