CK式搅拌槽流场数值模拟分析

Numerical Simulation Analysis on Flow Field of CK Stirred Tank

采用Mixture模型、多重参考系(Multiple reference frame,MRF)对CK式搅拌槽内流场进行数值模拟,分析其内部流场特性。结果表明,CK式搅拌槽内部流场主要由一个主循环流与两个小循环流构成,搅拌槽内流体呈"W"形进行上下循环运动;其内部压力槽顶部与底部的压力最大然后逐渐向搅拌中心减小,这种压力分布有利于促进搅拌混合;提高搅拌转速,可加速搅拌槽内介质混合过程,缩短混合时间;该结构搅拌槽的临界悬浮转速为130.51 r/min,当转速达到190 r/min时桨叶运转100转时搅拌槽内固相基本达到均匀悬浮,表明该结构搅拌槽具有较高效率的搅拌效果。

The mixture model and the multiple reference frame(MRF)were used to simulate the flow field in a CK stirred tank to analyze the internal flow field characteristics.The results showed that the flow field of CK stirred tank was mainly composed of one main circulation flow and two small circulation flows.The fluid in stirred tank undergone upward and downward circulation followed the"W"cycle trajectory.The pressure on the top and bottom of the tank was the highest and then gradually decreased towards to the stirring center,and the pressure distribution can facilitate mixing.A short mixing time was obtained with increasing stirring speed.The critical suspension speed of the stirred tank was 130.51 r/min.When the stirring speed reached 190 r/min,the solid phase in stirred tank could be uniformly suspended after the blade ran 100 r,which indicated that the stirred tank had a high stirring efficiency.