Verification of Coarse-Grained CFD-DEM in Multiple Flow Regimes

Abstract: The calculating capacity of traditional computational fluid dynamics-discrete element method (CFD-DEM) decreases with the increasing of tracking particles. The coarse-grained CFD-DEM can fewer the number of particles to be tracked and the collisions occur between particles by lumping several real particles into a coarse-grained parcel (CGP). The coarse-grained CFD-DEM was used to simulate the gas solid flow characteristics of different regime of fluidized beds (i.e., bubbling fluidized bed, spouting fluidized bed and circulating fluidized bed). The results of coarse-grained CFD-DEM were compared with the CFD-DEM simulation and experimental measurement. The characteristics of gas-solid flow were accurately predicted by coarse-grained method and compare well with traditional CFD-DEM and experiment data. Comprehensive assessment of coarse-grained CFD-DEM in predicting solid velocity is investigated in current work, while most of previous literatures force on the parameters of gas phase. What is worth mentioning is that coarse-grained CFD-DEM can observably improve the computational efficiency. The efficiency of coarse-grain method is about 5-8 times compares with the traditional CFD-DEM when the coarse-grained ratio is 2. Accordingly, the accuracy of coarse-grain method is validated in multiple flow regimes and the coarse-grained method can accelerate the calculation speed compared with the traditional CFD-DEM.