Numerical analysis of gas-solid flow in a novel spouted bed structure under the longitudinal vortex effects

The longitudinal vortex technology is adopted in the spouted bed so as to strengthen the particles radial mixing between spout and annulus zones. Three dimensional gas-solid two phase flow characteristics in a novel spouted bed structure under the longitudinal vortex effects was numerically investigated by two-fluid model (TFM) with kinetic theory for granular flow. Simulations and analyses have been conducted on three types of spouted beds: without disturbance units, with a pair of balls and with a pair of longitudinal vortex generators (LVGs). The simulation results show that: the fountain height decreases significantly when LVGs are installed in spouted bed, causing the secondary vortex flow. A pair of symmetrical distribution longitudinal vortex appear in the cross section of spouted bed under the action of LVGs, both for the gas phase and particle phase. The particle volume fraction near the central spout region, the radial velocity and granular temperature of particle phase in spouted bed can be promoted significantly by longitudinal vortex. Also, the value of turbulent kinetic energy of gas phase can be obviously enhanced by longitudinal vortex along the axial direction in spouted bed. As a result, the radial mixing of particles and gas phase between central spout and annulus in spouted bed can be significantly enhanced by the longitudinal vortex.