不同压力下喷动流化床气固流动特性的数值模拟研究

Numerical simulation on flow characteristics of spout-fluid bed in different pressures

采用非稳态欧拉-欧拉多相流模型、双方程湍流模型,对喷动流化床内的颗粒混合特性进行数值模拟,考察了压力对喷动流化床流动特性的影响。数值模拟研究结果表明:随压力增大,床层内稳定喷动区域增大,压降波动减小,流化工况更稳定。压力的增大促进喷动气的扩散,但对流化气的扩散起到抑制作用。当压力增大到一定程度后,床层空隙率的变化变小,压力对气固两相混合影响的作用趋向减弱。

Numerical simulation on particle mixing characteristics of spout-fluid bed were based on un-steady eulerian multi-phase flow model and standard k - ε turbulence equation. The effect of pressure on flow characteristics of the spout-fluid bed was analyzed through numerical simulation methods. The results show that the stable spouted area in the bed increase with the increase of the working pressure. The fluctuation of pressure drop decreases with the increase of the working pressure. The conditions of flow become more stable with the increase of the working pressure. The increase of pressure promotes the diffusion of spouting gas, while inhibits the diffusion of convection gas. When the pressure increases to a certain extent, the changes of bed void volume become smaller, the pressure on the effects of gas-solid two-phase mixing tend to diminish.