Numerical Simulation of Cohesive Particles in a Fluidized Bed by the DEM Coarse Grain Model

Abstract

The Discrete Element Method (DEM) is widely used in computational granular dynamics. The DEM is a Lagrangian approach where individual particle is calculated based on the Newton's second law of motion. Hence, the DEM enables us to investigate the granular flow characteristics at the particle level. On the other hand, the DEM has a difficulty to be used in large-scale powder systems because the calculation cost becomes too expensive when the number of particles is huge. Consequently, we have developed a coarse grain modeling as a large scale model of the DEM. The coarse grain particle represents a group of original particles. The coarse grain model was applied in typical gas-solid and solid-liquid two phase flows. The cohesive force like the van der Waals force was not considered in these simulations. In the present study, the coarse grain model is evolved to simulate the cohesive particles by considering the interparticle van der Waals force. The adequacy of the coarse grain model is proved by comparing the simulation results of original particle system. It is shown that the coarse grain model considering the interparticle force can simulate the original particle behavior precisely.