Discrete Element Simulation of Gas-Solid and Gas-Liquid-Solid Flows

Multiphase flow (i.e., gas-solid flow and gas-liquid-solidflow) extensively exists in industries, yet the strong coupling betweendifferent phases poses challenges in the discrete element method (DEM)-basedmodel establishment. This work developed a fully coupled frameworkby combining computational fluid dynamics (CFD) with DEM, with thefurther extension to incorporate volume-of-fluid (VOF) to study multiphaseflow systems. A smoothing method is implemented to allow the gridsize to be close to or smaller than the diameter of the particles,benefiting the subsequent interphase and interfacial interactionscalculation. Iso-Advector, an advanced VOF-based surface-capturingmethod, is further introduced to describe interface evolution andinterfacial interactions effectively. The integrated model is verifiedin three benchmark cases, i.e., a quasi-two-dimensional spouted bed,a fully three-dimensional spout-fluid bed, and a dam-break flow. Thenumerical results agree well with experimental measurements, confirmingthe model's reliability in simulating multiphase flow systems.