三维整体式喷动-流化床结构优化与流动数值模拟  

Numerical simulation and structure optimization on fluid flow behavior of three-dimensional integral multi-jet spout-fluidized bed

作　　者：杨春玲 白谨豪 吴峰[1] 马晓迅[1,2] 杨剑 YANG Chun-ling;BAI Jin-hao;WU Feng;MA Xiao-xun;YANG Jian(School of Chemical Engineering,Northwest University,Chemical Engineering Research Center of the Ministry of Education for Advanced Use Technology of Shan bei Energy,Xi'an 710069,China;Shan xi Research Center of Engineering Technology for Clean Coal Conversion,Xi'an 710069,China;School of Energy and Power Engineering,Xi'an Jiao tong University,Xi'an 710049,China)

机构地区：[1]西北大学化工学院,陕北能源先进化工利用技术教育部工程研究中心,陕西西安710069 [2]陕西省洁净煤转化工程技术中心,陕西西安710069 [3]西安交通大学能源与动力工程学院,陕西西安710049

出　　处：《高校化学工程学报》2019年第6期1415-1423,共9页Journal of Chemical Engineering of Chinese Universities

基　　金：国家自然科学基金(21878245);中国博士后科学基金第8批特别资助项目(2015T81048);陕西省自然科学基金(2019JM-039)

摘　　要：为了对环隙区内的颗粒堆积层产生局部流化作用,提出了一种在喷动床锥体处开一定数量侧喷嘴的整体式多喷嘴喷动-流化床结构,并采用双流体模型(TFM)对三维整体式多喷嘴喷动-流化床内的气固两相流动行为进行了数值模拟。通过计算流体力学(CFD)模拟获得了喷动床内颗粒体积分数、颗粒速度及流场均匀度分布情况,并将模拟结果与传统喷动床进行了对比,同时对锥体处开孔直径等关键参数进行了优化分析。结果表明:与常规喷动床相比,三维整体式多喷嘴喷动-流化床结构能有效增强喷动床环隙区与喷射区颗粒的径向混合,特别是流化了喷动床环隙区底部颗粒的流动死区。颗粒流场均匀度(CV)值随着床层高度的增加而上升,表明多喷嘴对颗粒流场的均匀化效应主要体现在喷动床柱锥区,当Ai/Az=0.67时,侧喷嘴对喷动-流化床内整体的颗粒流化作用达到最佳。In order to obtain local fluidization at particle accumulation layer in the annulus region of spouted beds, circular orifice side-jets were opened on the cone side of the spouted bed, which were regularly distributed in three-dimensional space. A three dimensional multi-jet spout-fluidized bed structure was numerically simulated using two-fluid model(TFM) incorporating the kinetic theory of granular flow. The distribution of particle volume fraction, particle velocity and uniformity of flow field in spouted bed was obtained by CFD, and the simulation results were compared with a conventional spouted bed. Key parameters such as the diameter of side-jets was optimized and analyzed. The results show that compared with simulation results in conventional spouted beds, the integral multi-jet spout-fluidized bed structure can effectively enhance radial mixing of particles in annulus and spout zones of spouted beds, especially fluidize particles in the flow dead zone at the bottom of annulus. The value of particle flow field uniformity increases with the increase of bed height, which indicates that the uniformity effect of Multi-Jets on particle flow field is mainly reflected in the conical zone of spouted beds. The best effect of side-jets on particle fluidization in spout-fluidized beds is obtained at Ai/Az=0.67.

关 键 词：流化床 多喷嘴喷动 气固两相流动 三维 流场均匀度 数值模拟 

分 类 号：TQ021.3[化学工程]