Comparison of flow microdynamics for a continuous granular mixer with predictions from periodic slice DEM simulations

Abstract

Using periodic slice discrete element method (DEM) simulations to model sections of a full continuous blender offers significant savings in computation cost. Before development of a periodic slice based continuous mixer model, the accuracy of periodic slice models for predicting full blender behavior needs to be examined. Flow microdynamics obtained from periodic slice simulations are compared against full blender results by examining speed and velocity frequency distributions. The periodic slice models are found to replicate full blender flow microdynamics well for central sections of the full blender. Reasonably good agreement is obtained for the inlet and outlet regions where the periodic boundary assumption is less valid. Results suggest that the use of periodic slice simulations to represent full blender behavior is a feasible approach which may be extended in the future to develop a full blender model. A small change in particle size is observed to have a negligible effect on the fill level of the continuous mixer, suggesting that larger particles may be used in DEM simulations to predict bulk flow quantities.