A clouded bubble-based drag model for the simulations of bubbling fluidized beds

A clouded bubble-based (CBB) drag model is developed in view of gas flow patterns around the clouded bubble. The bubble cloud is taken as the inter-phase between the bubble phase and emulsion phase based on the muti-scale resolution of the heterogeneous system. Moreover, the non-uniform distributions of drag force in the bubble crown and wake as well as the bubble sides are considered. The structure parameters are obtained by solving a series of equations including the mass conservation equations and empirical or semi-empirical correlations. The heterogeneous drag model is implemented into the two-fluid model (TFM) for 2D & 3D simulations of bubbling fluidized beds with Geldart A/B and A particles. The results demonstrate that the simulated results using the CBB drag model agree better with the experimental results compared to the homogeneous drag model and the structure-based drag model without the bubble cloud effect.