Modelling of particulate and fluid flow in laboratory scale SMDs using coupled DEM-SPH simulations

The stirred media detritor (SMD) is a common mill type used to achieve ultrafine grinds within the minerals industry. It is vertically orientated with a pin impeller. This study focusses on assessing the differences in fluid and particulate flow characteristics in three different laboratory scale SMD models. The computational model uses a two-way coupled discrete element method (DEM) and smooth particle hydrodynamics (SPH) configuration. The model was designed to simulate the mill chamber, impeller and grinding media using DEM, while the slurry was modelled as a semi-compressible fluid using SPH. The model computes the DEM and SPH components simultaneously and resolves their interaction forces through a coupling interface. Tip speed was varied in simulations and compared across mill sizes to examine the scale-up effects. Across the three mill scales, decreases are observed in the intensive collision energy and power draw, as the mill radius lengthens.