Abstract: The detached eddy simulation (DES) model was employed to study the fluid flow behavior in an unbaffled tank stirred by a Rushton impeller. The result of turbulent flow obtained by standard k-e model was used as an initial solution for faster convergence of DES computation. By comparison with the literature results of large eddy simulation (LES) and PIV data, it was found that DES model could capture the instantaneous turbulent flow characteristics. The mean velocity profiles obtained by DES model showed good agreement with the LES and experimental results. There was only a tiny discrepancy (within 7%) between the mean tangential velocity obtained by DES and PIV. The maximum discrepancy between the DES predicted mean radial velocity and PIV result was not more than 12%. The results show that DES model has high potential in predicting the turbulent flow in stirred tanks, it can provide velocity profiles almost as accurately as the LES model does. Meanwhile, the computation cost of the DES model is only about 1/3 of the DES model.

Key words: Rushton impeller, stirred tank, turbulent flow, detached eddy simulation

摘要： 采用分离涡模型对无挡板涡轮桨搅拌槽内的湍流流动进行了研究，重点分析了流场结构和速度分布，以检验该模型模拟搅拌槽内流体流动的有效性和正确性. 为了加快收敛，先采用标准k-e模型进行稳态流场计算，并以此结果为初始值进行分离涡模拟. 与现有文献大涡模拟及实验结果对比表明，分离涡模型能捕捉槽内流体的瞬时流动特征，获得的时均速度分布与大涡模拟及实验结果吻合较好，其中对切向速度分布的预测误差不超过7%，对径向速度分布的预测精度则低一些，局部误差接近12%. 分离涡模型适用于无挡板涡轮桨搅拌槽内湍流流动的模拟，能获得与大涡模拟相近的结果，且计算量更小(约为大涡模拟的1/3).

关键词: 涡轮桨, 搅拌槽, 湍流, 分离涡模拟