Study on Gas-Solid Two-Phase Flow in Spouted Beds

Spouted beds are widely used drying equipment in industry. The axial gas flow causes gas-solid two-phase flow with regularity. With the rapid development of hardware and calculation technique, numerical simulation has become an important method to study flow patterns.Euler-Euler two-fluid model is used in this paper, and standard k-εtwo gas-processing model of turbulent flow is applied. Several frictional stress models are introduced to accommodate the instantaneous contact of particles and the half-sustaining contact interaction in the dense zone. Simulations are also carried through on spouted-fluid bed and spouted bed with a draft tube as well.There are three flow zones in spouted bed according to simulation results: the spouted zone with low concentration and high axial velocity of particles; the annulus zone with dense particle flow in low speed and the fountain zone. The simulation result matches the experimental data. Flow parameters such as velocity and temperature of particles are also gained.In spouted-fluid bed, with fluid gas entered from the bottom of inverted cone, the contacts of gas and particle become violent in this area. The fluid gas effects well when enters from normal direction. The introduction of a draft tube causes more distinctness between the flow zones in spouted beds, brings equality to the distributions of particles in each zone. Gas-particle interaction happens mainly inside the drafted tube, and intense two-phase flow also appears around both ends of the tube.