Numerical investigation of gas-solid flow behavior in a novel integral multi-jet spout-fluidized bed

A novel integral multi-jet spout-fluidized bed (IMJSFB) is designed so as to reduce the dead zone at the bottom of the annulus and omit auxiliary equipment for bypass fluidizing air. The gas-solid flow behavior in the IMJSFB was numerically simulated using an Eulerian-Eulerian two-fluid model. A number of slits (4) were formed on the cone side of the cylindrical spouted bed to form an auxiliary multi-jet structure, which can create spoiler effects on the boundary of the pyramidal. The distributions of particle velocity and concentration in the IMJSFB were obtained by numerical simulation. The CFD results show that, compared with the conventional spouted beds, the IMJSFB structure can effectively enhance the particle's velocity in the annulus of the spouted bed (especially in destroying flow dead zone at the annulus). The enhanced particle motion significantly decreases the volume fraction of the boundary layer on the cone. The particle concentration and velocity distribution along the radial direction become more uniform, and the decrease in value of the coefficient of variation (CV) of the particles' velocity is 22.9% in IMJSFB. The turbulent kinetic energy of the gas phase can be significantly enhanced and the strengthening effect on the turbulent kinetic energy of the gas remains good with the increase of the bed height.