CFD-DEM-VDGM method for simulation of particle fluidization behavior in multi-ring inclined-hole spouted fluidized bed

The simulation of particle fluidization behavior in a complex geometry with a large number of particles is challenging owing to the complexity of unstructured computational grids and high computational intensity.In this study,a virtual dual-grid model(VDGM)is proposed to calculate the solid volume fraction in unstructured grids and speed up the calculation.The VDGM is coupled with a computational fluid dynamics-discrete element method model to simulate particle fluidization behavior in a multi-ring inclined-hole spouted fluidized bed with 4.2 million particles under a high temperature of 1423 K.A computational fluid dynamics-discrete element method-virtual dual-grid model(CFD-DEM-VDGM)coupling model is implemented based on commercial software Fluent and EDEM.The time step settings in Fluent and EDEM and the pattern of particle data transfer in Fluent are improved to speed up the calculation.It is discovered that the VDGM can calculate the solid volume fraction in unstructured grids of complex geometry and speed up the calculation effectively.The calculation speed increased by more than 10 times compared with that of the segmentation sampling method.The new pattern of particle data transfer in Fluent can reduce data transfer time by more than 90%.The fluidization behavior of 4.2 million high-density particles in the multi-ring inclined-hole spouted fluidized bed is obtained and analyzed in detail.The CFD-DEM-VDGM coupling method is validated for the bed expansion height and spouting cycle time in a spouted fluidized bed via experimental results.