CFD simulation of hydrodynamic characteristics in a multiple-spouted bed

In present work, the gas-solid two-phase flow in the multiple-spouted bed is simulated by the Eulerian-Eulerian approach, the Gidaspow drag model is chosen to describe the interface momentum exchange. The simulated results agree well with the experimental results from the literature. Then the detailed flow behavior in the multiple-spouted bed is investigated for 1.0. mm, 1.4. mm and 1.8. mm glass beads. The effect of the ratio of central/auxiliary and auxiliary/central gas flow on the hydrodynamic characteristics in the multiple-spouted bed is studied. The high velocity spouting gas dominates the flow pattern in the bed and restricts the development of the low velocity spouting gas. The distribution of voidage, the profile of particle velocity and the variation of particle volume concentration are obtained. The fountain height and spout diameter increases with increasing gas flow rate initially and then decreases. The increasing bed thickness has an obvious influence on the hydrodynamics in the bed. For Multi-spouting, the spout diameter increases with increasing bed height, however the bed becomes unstable when the bed thickness is increased to 200. mm. For Single-spouting, the fountain height decreases with increasing bed thickness, but the fountain width and the solid volume concentration in the fountain increases. The results of this study provide important information on the flow behavior within the multiple-spouted bed and may be helpful for better application of this type of spouted bed to the industrial process.