Experimental Study on Gas–Solid Flow in the Spouted Bed under Longitudinal Vortex Effect

To strengthen the particles radial movement and mixing, the longitudinal vortex generator of a sphere was adopted in the spouted bed in this study. To find the influence of the longitudinal vortex and particle properties on axial and radial velocities of particles in a 152 mm-diametered spouted bed, particle image velocimetry (PIV) was employed. The experimental results show that the addition of the longitudinal vortex generator caused the vortex movement of high-speed gas and induced a considerable secondary fine vortex in the cross section of the spouted bed, and the existence of longitudinal vortex significantly improved the radial velocity of particles, compared with that of the conventional spouted bed. Due to the effect of longitudinal vortex on particles, the phenomenon of early dropping of particles was increasingly obvious with the rise in bed height, and the value of axial velocity of particle phase was negative. With the decrease in the particle diameter, the longitudinal vortex effect of gas-driven particle movement would be enhanced. The longitudinal vortex could enhance particle velocity under a wide range of particle diameters, and the enhancement factor η decreased with the rise in the particle diameter and gradually approaches to 1.