Modeling and validation of coarse-grained computational fluid dynamics–discrete element method for dense gas–solid flow simulation in a bubbling fluidized bed.

This article focuses on the development and validation of a coarse-grained computational fluid dynamics–discrete element method (CG CFD–DEM) for simulating dense gas–solid fluidized beds. The CG CFD–DEM method reduces computational cost by grouping multiple smaller particles into larger parcels while accounting for energy dissipation from collisions within and between parcels, thereby preserving key flow characteristics. Experimental verification using high-speed photography and comparisons with traditional CFD–DEM simulations demonstrate that CG CFD–DEM accurately predicts transient spatial distribution, velocity, pressure drop, bed height, and particle mixing states under various operating conditions. Additionally, the method significantly decreases computation time—by over 55% at a coarse ratio of 1.6—making it a promising tool for large-scale engineering applications involving billions of particles with minimal loss of accuracy.