回料阀内气固两相流动特性的数值研究  

Numerical Study on Gas-Solid Flow Characteristics in Loop Seal

作　　者：王庆功[1] 杨海瑞[1] 吕俊复[1] 

机构地区：[1]清华大学热能工程系热科学与动力工程教育部重点实验室,北京100084

出　　处：《中国电力》2013年第7期1-5,共5页Electric Power

基　　金：国家科技支撑计划项目(2012BAA02B01)

摘　　要：为揭示回料阀内的负压差粘性滑移流动特性,基于浓相颗粒动力学理论,建立欧拉-欧拉模型对回料阀内的气固两相流动进行数值模拟研究,通过改变回料阀流化风和松动风风速、颗粒循环流率及回料腿出口背压等条件,详细分析了各工况下回料阀内的颗粒浓度分布、压力分布及气体反窜特征等,揭示了回料阀中的气固两相流动结构和变化特点。结果表明,回料阀中存在气体反窜现象;流化风和松动风风速越高,形成的气泡越多,气体反窜率越大;增加颗粒循环流率,颗粒携带气体现象更显著,气体反窜率减小;每增加返料腿出口背压1 000 Pa,料高增加约0.06 m,逆压差流动阻力增加,气体反窜率增加。Two-dimensional simulations of a pilot scale loop seal are mainly performed in this paper to reveal the viscous slip flow characteristics in negative pressure gradient. An Eulerian-Eulerian approach with constitutive relationships based on the kinetic theory of granular flow （KTGF） for dense gas-solid flows is used. By changing the fluidized-air/loose-air velocities, the particle circulation rate and the back pressure at the return leg, the flow characteristics including the distributions of particle concentration and pressure as well as the gas inverse flow phenomenon are carefully analyzed, thus the gas-solid flow structure and its variations are demonstrated. The results show that the gas inverse flow phenomenon does exist in loop seals. The higher velocity of fluidized-air or loose-air, the more bubble will come up with higher gas inverse flow rate. By increasing the particle circulation rate, particles will carry more air, resulting in the reduction of the gas inverse flow rate. By every 1000Pa increase of the back pressure, the packed height of the particles in the standpipe will rise by about 0.06m and the gas reverse flow rate will also increase as a result of more flow resistance in negative pressure gradient.

关 键 词：回料阀 流动特性 数值模拟 气体反窜 

分 类 号：TK229.66[动力工程及工程热物理—动力机械及工程]