Fluid-solid interaction simulation for particles and walls of arbitrary polygonal shapes with a coupled LBM-IMB-DEM method
To achieve simulating the fluid-solid systems which consist of irregular polygonal particles and walls, an improved and extended LBM-IMB-DEM model has been developed. The method couples the Lattice Boltzmann Method (LBM) for fluid flow calculation, the polygonal Discrete Element Method (DEM) for particle-particle and particle-wall interactions computation, and the Immersed Moving Boundary (IMB) scheme for fluid-solid interactions calculation. The Convex Decomposition method is proposed as an extension of polygonal DEM, which successfully expands the applied range to arbitrary polygons. A series of optimization algorithms and flowchart designs are adopted, including the improved progressive scanning algorithm and the proposed solid volume fraction fast algorithm, which can effectively increase the computational efficiency. The model is comprehensively validated by performing several verification simulations, the results of which are consistent with the existing literature and theoretical data. The simulation of the representative engineering process, clean bed filtration of irregular airborne particles in porous media, is then accomplished as the application test. The results have proved that the proposed LBM-IMB-DEM is a promising model which has satisfactory adaptability and computational efficiency for simulating complex fluid-solid systems, which will help complement the experimental research into such multiphase systems.
Keywords: Lattice Boltzmann method, Discrete element method, Immersed moving boundary, CFD, Non-spherical particulate system, Filtration,