Numerical studies of liquid-solid fluidized bed separator using CFD

The gas-liquid flow fields of Liquid Solid Fluidized Bed Separator ( LSFBS) were simulated using VOF (Volume of Faction) multiphase model with the RNG k-ε Model as a turbulence closure model. After the relatively stable two-phase flow fields were reached,the separation processes in the LSFBS of multi-solid particles with different sizes and densities were simulated using the Lagrangian Discrete Phase Model ( DPM). The simulation results match well with the experimental results. The root-mean-square error (RMSE) between the predicted separation results and the experimental values is 2. 47 while the relative error of predicted clean coal yield is 2. 38% . The distribution of LS- FBS’s velocity fields was discussed. The impacts on the separation performance of the upward currents’ flow rate as well as the pulsating upward currents’ cycles and waveforms were explored. The mathematical relationships between separation density and upward current rate,Ep value and upward current rate were set up. According to the simulation results,the separation performances of steady upward currents are better than those of pulsating upward currents. For pulsating upward currents,the optimal cycle is 1. 25 s while the best waveform is rectangular.