(90e) Modeling a Continuous Granular Mixer: Periodic Slice DEM Models Vs. Full Blender DEM Simulations

Sarkar, A. - Presenter, Purdue University
Wassgren, C. R. - Presenter, Purdue University

Periodic boundary conditions have often been used in discrete element method (DEM) simulations to model larger granular systems. Using a thin periodic slice has the potential to offer considerable savings in computation time. However this approach is limited to systems where the axial gradients are usually negligible compared to the transverse components, e.g. a rotating drum. In this current work, a methodology is proposed for using periodic slice simulations to model a continuous blender system with non-negligible axial gradients. The powder fill level and average axial speed vary along the periodic direction. The use of periodic slices to break down the full blender into smaller sub-simulations results in a significant reduction in computational runtime due to fewer simulated particles and shorter simulation time required to extract relevant information. The current work compares results from periodic slice DEM simulations to full blender DEM simulations results in order to determine what flow information can be extracted from the smaller scale, periodic slice simulations. Agreement between residence time distribution, velocity profile, and mixing indices suggests that this modelling approach can produce reasonable predictions of flow and mixing behaviour.