Visualization study on the coarse graining DEM for large-scale gas–solid flow systems

Abstract Gas–solid flows are ubiquitous in industrial systems. The coupled model of the discrete element method (DEM) and computational fluid dynamics (CFD) is one of the techniques for the simulation of the gas–solid flows. To enhance the applicability of the DEM-CFD method, the coarse graining DEM has been developed to simulate large-scale powder systems. The coarse graining DEM is a scaling law model and hence can simulate large-scale systems using a smaller number of particles than the actual one. Although the coarse graining DEM enables to effectively simulate large-scale powder systems on a single PC, visualized image is lack of reality due to reduced spatial resolution. Here a novel visualization method is developed to produce realistic images. In the proposed technique, the virtual particles are located by considering the motion and location of the coarse grain particles. To show the adequacy of the proposed method, two types of visualization based on the computational results are made: a blow-up of powder due to injected gas flow and a spouted bed. In these systems, the visualized images are shown to be improved by the proposed visualization technique. The effectiveness of the proposed method is proved by the agreement of the images based on the calculation results between the standard DEM-CFD method and coarse graining DEM.

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