Experimental and computational investigation on hydrodynamics in high-density liquid-solid circulating fluidized bed
Hydrodynamic behavior in a high-density liquid-solid circulating fluidized bed (HDLSCFB), 80 mm in ID and 8000 mm in height was investigated experimentally and computationally.The experiment found that both the radial particle hold-up and velocity distribution in the riser was parabola-shaped, while the axial average particle hold-up and velocity distribution was wave-shaped, indicating that the glass beads particles in the riser experienced a second acceleration process before reaching a fully developed flow at the top section of the riser.This was believed to be closely related to the high particle hold-up in the riser,high Ul and Gs as well as the application of tubular distributor at the bottom of the riser.The experimental results also showed that the profile of the particle residence time distribution of LSCFB had a sharp narrow symmetrical peak with no tail, suggesting a rather uniform residence time distribution of solids, a small extent of solids dispersion and a plug flow-like structure.CFD simulation results agreed well with those obtained by experiment, indicating that the computational model was suitable for simulation and prediction.Based on the computational model, the influence of particle density and diameter on the hydrodynamics was also predicted.