Massively speeding up DEM simulations of continuous processes using a DEM extrapolation

The discrete element method (DEM) is widely used to tackle problems associated with granular material processing. Its applications are diverse, ranging from powder mixing to transport and fluidized beds. Computational costs are a major issue with regard to DEM. Long process times combined with a large numbers of particles require simulations that can last months. In this paper we apply an extrapolation method based on pseudo-steady state DEM bulk behavior to allow for the long repetitive process to be completed. The extrapolation method is applied to two processes relevant to the pharmaceutical industry: continuous mixing and a tablet press feed frame. The results of the extrapolation method are validated against full DEM simulations of the complete process in terms of residence time, travel distance, and velocity distributions. The DEM extrapolation for pseudo-steady state processes resulted in an enormous reduction of the simulation time, while retaining residence times, travel distance and velocity distributions.