气固流化床内鼓泡行为的离散颗粒数值模拟  

Discrete Particle Simulation of Bubbling Behavior in a Gas-Solid Fluidized Bed

作　　者：吴春亮[1] 詹杰民[2] 

机构地区：[1]广东海洋大学工程学院,广东湛江524088 [2]中山大学应用力学与工程系,广东广州510275

出　　处：《过程工程学报》2007年第3期432-438,共7页The Chinese Journal of Process Engineering

摘　　要：采用离散颗粒数值模型探讨了气固流化床内多个气泡的运动规律.数值计算考虑了颗粒与气体的相互作用以及颗粒间的相互作用,颗粒与气体的相互作用采用Gidaspow阻力修正公式,颗粒间的相互作用则采用硬球碰撞模式描述.给出了一种在二维非结构网格下精确计算颗粒体积分数及两相全隐耦合求解颗粒速度的方法,同时,在硬球模型中对颗粒碰撞事件采用散列表的处理方法,大大提高了计算效率.数值计算结果表明,由于多个气泡的相互作用而导致气泡的横向运动显著,气泡运动轨迹与气泡形状依赖于流化床内静压力的分布,气泡总是选择压力小、压差梯度大的路径上升,这一现象与气液分离流中气泡的运动规律类似.The bubbling behavior in a two-dimensional fluidized bed is numerically studied using the discrete particle simulation model. Inter-particle interactions are taken into account, which are described by binary collisions in a hard-sphere model. The interactions between the particulate and continuous phases are modelled by the Gidaspow＇s drag formula. The particle momentum equations are solved simultaneously with the gas governing equations, and the void fraction is calculated in a particular way. The hash table is introduced to deal with collision events and shortens the computing time. The numerical results indicate that the bubble transverse movements are enhanced by the interaction among bubbles in the fluidized bed. The trajectories and shapes of bubbles are dependent on the static pressure distribution in the bed and bubbles move towards the area with lower pressure and a larger pressure drop. This phenomenon is similar to that in the gas-liquid separate flow.

关 键 词：气固流化床 离散颗粒模型 硬球模式 

分 类 号：TQ013.2[化学工程]