不同入口结构下行床内气固流动及混合行为的CFD-DEM模拟  

CFD-DEM simulation of flow and mixing behavior in downers with different entrance structures

作　　者：赵永志[1] 程易[1] 丁宇龙[1] 金涌[1] 

机构地区：[1]清华大学化学工程系,绿色反应工程与工艺北京市重点实验室,北京100084

出　　处：《化工学报》2007年第6期1396-1403,共8页CIESC Journal

基　　金：国家自然科学基金项目(20306012);全国博士学位论文作者专项资金项目(200245);中国博士后基金项目(2005038061)。~~

摘　　要：采用计算流体力学和离散单元模型(CFD-DEM)耦合一种简单的气固催化反应模型,对具有不同入口结构的二维下行床内的气粒流动和混合行为进行全床数值模拟。模拟得到了不同入口结构下行床内的多尺度气固运动状态、全床的颗粒含率、速度及反应生成物浓度分布,以及气体和颗粒在下行床内的停留时间分布,发现入口结构对反应器内的流动、混合和气固接触效率起着关键性的作用,入口气体和颗粒的不均匀分布将导致下行床内气体停留时间的宽分布以及气固接触效果的恶劣。The gas-solid flow and mixing behavior in two dimensional downers with different entrance structures were simulated by using a CFD-DEM method. A gas-solid catalytic reaction model was incorporated in the governing equations to investigate the contact efficiency between phases. The simulations showed the dynamic and time-averaged flow structures characterized by the distributions of solids fraction, particle velocity and the reaction product in the whole downer as well as the residence time distributions （RTDs） of gas and solids, which were all heavily influenced by the design of the entrance structure. Non-ideal initial contact between gas and solids would cause wide RTDs of gas and worsen the reactor performance.

关 键 词：下行床 入口结构 气固接触 计算流体力学 离散单元法 

分 类 号：TQ018[化学工程]