立式搅拌槽中挡板结构对搅拌能耗影响的数值模拟  

Numerical Simulation of Influence of Baffle Structure on Stirring Energy Consumption in Vertical Stirred Tank

作　　者：许卓[1] 赵恒文[1] 郑建坤[1] 

机构地区：[1]河海大学能源与电气学院,江苏南京211100

出　　处：《水电能源科学》2013年第5期162-165,197,共5页Water Resources and Power

摘　　要：以立式搅拌槽为基础,借助Fluent软件κ-ε湍流模型,研究了直叶涡轮和斜叶涡轮的搅拌机内部流动,分别对标准、倾斜、离底、底部十字等不同结构挡板在搅拌槽内以恒定转速200r/min旋转时的工作状态进行了数值模拟,获得了8种情况下的功率,并据此对比速度矢量图、湍流图、速度分布曲线分析功耗改变的原因。结果表明,倾斜挡板可有效减少功率消耗,且物料在挡板处不易形成死角,工业上可采用此挡板优化搅拌功耗。底部十字挡板的流场湍流强度最大,若圆柱回转区的半径为定值时,采用底部挡板可有效防止底部固体颗粒的堆积,优化搅拌效果。若在多相搅拌过程中通过改变挡板安装方式达到颗粒沉淀、较高粘度液体充分混合等目的,需采用直叶径向流叶轮,在功率输入一定的情况下可得到合适的流场。Based on the vertical stirred tank, the κ-ε turbulent model in Fluent software is used to study the internal flow of standard and inclined turbine mixer. The operating state of different baffle structure is simulated under constant rotational speed 200 r/min, which includes standard baffle, inclined baffle, off-bottom baffle and bottom-cross baffle. Stirring energy consumption is obtained for eight operating conditions. And then the cause of energy consumption change is analyzed by comparing velocity vectorgraph, turbulent graph and velocity distribution curve. The results show that the inclined baffle can effectively reduce the stirring consumption energy; the material does not form the dead angle in the baf- fle; the baffle can be used to optimize stirring consumption energy in industry; the turbulence intensity of flow field for bottom-cross baffle is significantly higher; the bottom baffle can effectively prevent solid grain deposit and optimize stirring effect if the radius of cylindrical rotation area is constant; it is necessary to use standard turbine and appropriate flow filed with fixed power for achieving grain deposit and mixing high viscosity liquid fully by change of the baffle installation style in multi-phase stirring process.

关 键 词：档板结构 搅拌能耗 功率 数值模拟 

分 类 号：TK730.2[交通运输工程—轮机工程] TH12[动力工程及工程热物理—流体机械及工程]