Numerical simulation of polydisperse particle segregation based on a bubble-based drag model

This work is devoted to the development of a novel polydisperse drag model based on particle type for bubbling fluidized beds. Traditional homogeneous drag models do not take into account the heterogeneous mesoscale structures, while this model is a mesoscale-structure-dependent drag model. The model combined with Energy Minimum Multiscale (EMMS) theory has been successfully applied to the simulation of polydisperse particle segregation. Four particle size distribution (PSD) systems (including a binary system with different sizes, a binary system with different sizes and densities, a normal PSD and a lognormal PSD) were selected to validate the model under various superficial gas velocities. The PSD was decomposed into several types of solids, each governed by its own set of hydrodynamic equations. The solution algorithm was able to find the heterogeneous index for each solid, which was dependent on both slip velocity and solid concentration. Experiments were subsequently conducted under identical conditions to compare the experimental data with the simulated data. The average relative error between the simulation data and the experimental data about the mean particle size distribution was less than 5%. These results indicated that the proposed model outperformed other drag models in accurately predicting particle segregation behavior.