(701e) Development and Validation of a Comprehensive Drag Model for Simulating Gas-Solid Fluidization in Dense and Dilute Regimes

Two-fluid modeling has been widely used to simulate large-scale fluidized beds, and exhibiting a significant dependence on drag models. In this study, a comprehensive drag model including the whole flow regimes for gas-particle flows is proposed to simulate the hydrodynamics of gas-solid two-phase flow. It combines both the Wen & Yu drag model and the Ergun drag model by a method that is theoretically according to flow regimes. This new drag model is validated with experimental data from spout fluidized bed, bubbling fluidized beds and riser, and compared with simulation results predicted with previous drag models. A computational study was carried out by means of a Two-Fluid model (TFM) based on the kinetic theory of granular flow (KTGF) to explore the influence of the interactions between gas and particles on the formation of heterogeneous flow structure. It is found that the experimental and computed particle velocity profiles show good agreement when using this proposed model in the spout fluidized bed. A better prediction of the solid concentration near the walls of the fluidized bed was obtained due to its favorable feature of dealing with particle concentration transition.

Keywords: Fluidized bed, Two-fluid model, Drag model, Kinetic theory of granular flow