Numerical and experimental study of integral multi-jet structure impact on gas-solid flow in a 3D spout-fluidized bed

Abstract

Abstract In this study, the impact of multi-jet structure on the gas-solid flow in a three-dimensional integral multi-jet spout-fluidized bed was investigated using both numerical and experimental methods. Particle Image Velocimetry (PIV) was applied to analyze the difference made by integral multi-jet to the movement of particles in a 152-mm-diametered spouted bed. The Eulerian-Eulerian approach was adopted. Compared with the conventional spouted bed, the addition of the side jet facilitates particles to generate a substantial amount of secondary eddies and the movement of particles can be effectively enhanced in the cross section of the multi-jet spout-fluidized bed. When the number of side jets approached N = 18, the particle concentration in the annulus region was shown to to be extremely low. Considering the pressure drop of the spouted bed, the comprehensive optimum number of side jet of spouted bed was set to N = 24. Besides, there existed an optimum side jet diameter D = 4 mm, at which the side jet exerted the optimal fluidizing effect on the gas-solid two-phase flow in the multi-jet spout-fluidized bed. The distribution structure of the side jets with lower density, upper sparseness and symmetry contributed to the local fluidization of the inlet gas in the dead zone, and Case D demonstrated the full fluidizing effect on the particles in the multi-jet spout-fluidized bed.