流化床密相区流动特性的数值模拟  

Numerical Simulation of Flow Characteristics in the Dense-phase Zone of a Fluidized Bed

作　　者：徐祥[1] 向文国[1] 秦成虎[1] 

机构地区：[1]东南大学洁净煤发电及燃烧技术教育部重点实验室,江苏南京210018

出　　处：《热能动力工程》2004年第2期131-133,共3页Journal of Engineering for Thermal Energy and Power

基　　金：国家自然科学基金资助项目(虚拟流化床仿真研究50176010)

摘　　要：流化床内气固两相流动一直是实验研究和数值模拟的热点。基于Eulerian双流体模型,本文建立了流化床内的气固两相流动模型,采用FLUENT软件对流化床密相区两相流动特性、床内气泡的产生运动和爆裂等特性进行了数值模拟。模型中,将颗粒相看作是连续介质,建立与气相相同形式的数学模型;采用了离散介质动力理论,引入颗粒温度来描述固相粘性应力,并用气固曳力进行气固两相耦合。模拟得到了气泡产生、运动和爆裂的变化过程,与实验结果相一致。采用不同的曳力模型对流化床稠密两相流动进行了模拟,与Kuipers实验对比,结果表明采用Gidaspow曳力模型描述流化床稠密两相流动特性更准确。Based on an Eulerian two-fluid model, a model was set up for the gas-solid two-phase flow in a fluidized bed. By making use of FLUENT software a numerical simulation was conducted of the two-phase flow characteristics in the dense-phase zone of the fluidized bed, and the characteristic features of the generation, movement and explosion/cracking of in-bed gas bubbles. In the model a particle-phase is treated as continuous media. A mathematical model identical in form to the gas phase was established. By utilizing the dynamic theory of discrete media the concept of granular temperature was introduced to describe the viscous stress of a solid phase. Moreover, a gas-solid two-phase coupling was accomplished by the use of a gas-solid drag force. By way of simulations a transformation process was obtained of the generation, movement and explosion/cracking of gas bubbles, which has been found to be in full agreement with experimental results. By using different drag force models a simulation was performed of the fluidized bed dense two-phase flows. A comparison with Kuipers experimental results shows that the use of a Gidaspow drag force model can result in a more accurate description of the dense two- phase flows in the fluidized bed.

关 键 词：Eulerian模型 气固两相流 气泡 流化床 

分 类 号：O359[理学—流体力学]