Solid Suspension in Stirred Vessels: Comparison of a Fully Coupled CFD-DEM and an Eulerian Multiphase Approach

Solid suspension in high viscous liquids and/or with high solids concentration is a challenging problem due to the solid-solid and solid-liquid phase interactions. Just suspended speed (N_js), suspension height (H_s) and the power consumption can vary not only with the material properties but also with the design of tank and impellers.

In the past, there was been work presented using multiphase CFD methods, specifically the Eulerian approach. This approach has shown promising results for turbulent conditions [1]. Further work has also been carried out where Discrete Element Modeling for particle flows was co-simulated with CFD simulations for fluid flow [2].

In this work we compare based on experimental data simulation results of fully 2-way coupled CFD-DEM simulations with an Eulerian Multiphase (EMP) approach based on the Kinetic Theory of Granular Flow (KTGF) in terms of accuracy and runtime. While the CFD-DEM simulation typically needs more runtime, it needs less model parameter determination and tuning than the EMP approach.

[1] R. Aglave, J. Feng, E. Janz, R. Strong and T. Eppinger, CFD Simulation of Solids Supension at High Loading, AIChE annual meeting 2015, Salt Lake City, UH, USA

[2] B. Blais, M. Lassaigne, C. Goniva, L. Fradette and F. Bertrand, 2015. A Robust and Efficient CFD-DEM Model for the Investigation of Viscous Solid-Liquid Mixing in Stirred Tanks, 10th European Conference on Chemical Engineering, Nice, France.