CFD-DEM simulations of solid-liquid flow in stirred tanks using a non-inertial frame of reference

Mixing applications operating in the laminar regime are used in numerous industrial processes in the pharmaceutical, chemical, and food industries. The aim of this paper is to introduce a numerical model adapted to solid-liquid mixing situations in stirred tanks. The method presented herein is based on a Euler-Lagrange approach using the CFD-DEM method. This method couples computational fluid dynamics (CFD) for the fluid with the discrete element method (DEM) for the solid particles. We introduce a rotating frame of reference approach, which is the first of its kind for CFD-DEM. In this paper we discuss the main issues related to the modeling of complex rotating impeller geometries, we explain the various issues involved in conducting a CFD-DEM simulation in a non-inertial frame, we compare our model with experimental results obtained with a pitched blade turbine and, lastly, we use our model to study solid-liquid mixing with a double helical ribbon.