New structure-based model for Eulerian simulation of hydrodynamics in gas–solid fluidized beds of Geldart group “A” particles

Abstract

The well-documented inaccuracy of conventional two-fluid modeling of hydrodynamics in fluidized beds of Geldart Group A particles is revisited. A new force-balance (FB) sub-grid-scale model, applied to the conventional Wen–Yu drag correlation, analyzes the balance of van der Waals, drag, gravity and buoyancy forces. It predicts formation of agglomerates inside the bed, updating the drag calculations by applying a correction factor to the conventional drag models to account for agglomerate formation. Good predictions were obtained of fluidization regimes and bed expansion, and there was promising agreement with experimental time-average radial voidage profiles reported by Dubrawski et al. (2013). Good quantitative agreement between DEM and two-fluid predictions of minimum bubbling velocity was also observed when the model was used to predict minimum bubbling velocity, in contrast to the predictions from a non-cohesive, Wen–Yu model. Further evaluation studies are required to test the ability of the new model to predict the properties of larger-scale fluidized beds.