Coarse-grained CFD-DEM simulations of fluidization with large particles

Detailed validation coarse-grained CFD-DEM model in the open source code MFIX is performed. Metrics used include fluidization behavior, minimum fluidization velocity, averaged pressure drop, mean and rms particle velocity. The choice of the spring constant alters fluidization dynamics. Of drag correlations tested, the Tang et al. (2015) formed poorly overall at low superficial velocities of 2 Umf and 3 Umf and exceptionally well at 4 Umf suggesting it is suitable at higher velocities. A deterioration in the predicted minimum fluidization velocity is noticed using the coarse-grained model. A trend of reducing error of average pressure drop with increasing statistical weight is observed at low gas velocities. The mean particle velocities profiles for the coarse grain and conventional CFD-DEM models do not show appreciable differences unlike rms profiles that exhibit a reducing trend with increasing statistical weight. Some gain on the wall clock time required to complete a case were recorded.