CFD-DEM Simulation of a Fluidized Bed of Particles with Inter-Particle Cohesive Force

Gas-solid fluidized beds with the cohesive particles are applied widely in industry, while agglomeration and poor fluidization could happen as a result of inter-particle cohesiveness. Different methods for incorporating cohesive force with CFD-DEM models are discussed.
In this paper, a hysteresis contact model is coupled with CFD-DEM model. The fluidization characteristics of the cohesive particles under different conditions in a 2D fluidized bed are simulated. Generally, it is found that with increasing inter-particle cohesiveness, the particles begin to be agglomerated and the bubbles become gas channels. By increasing the cohesiveness, particle velocity decreases generally and the internal recirculation of cohesive particles is restrained. The fluctuation of particle velocity decreases generally and the probability density of particle velocity around zero increases. When the cohesiveness is increased further, the internal recirculation of particles is restrained and the gas channels become stable. Also, the fluidization of cohesive particles under different conditions in a 2D fluidized bed with immersed tubes is simulated. The immersed tubes play the frameworks promoting the formation of gas channels.