Abstract: Gas-liquid turbulent flow in a side-entering stirred tank with φ1.5 m×1.2 m was simulated with computational fluid dynamics (CFD).Three interface boundary conditions (pressure-outlet,velocity-inlet and degassing boundary)and two drag force models(standard S-N model and Brucato-Tsuchiya model)were presented and respectively coupled with the Euler-Euler model and dispersed two-phase k-ε turbulence model by using user define function (UDF).The impeller power number,total gas holdup and gas phase distribution in the tank were calculated and compared with the measurements of the cold model experiments to investigate the effect of boundary condition of gas-liquid interface and drag force model on prediction accuracy.The results indicated that the predicted results calculated with the CFD model coupled with the Brucato-Tsuchiya model and adopting the velocity-inlet or degassing boundary condition,were in agreement with the experimental results,much better than the pressure-outlet boundary condition.

Key words: side-entering stirred tank, gas-liquid flow, computational flow dynamics, boundary condition, drag force model

摘要： 采用计算流体力学(CFD)技术对φ1.5 m×1.2 m侧进式气液搅拌釜内气液两相流场进行数值模拟,检验了3种气液分界面边界条件和两种相间曳力模型。通过UDF程序将上述模型分别与欧拉双流体模型和 dispersed k-ε 两相湍流模型进行耦合计算,得到搅拌功率准数、总体气含率和气相分布,并与冷模实验结果进行对比,得到能准确预测的CFD模型。研究结果表明,3种气液界面边界条件下采用标准S-N模型计算所得的功率准数和气体分布误差均较大,而Brucato-Tsuchiya模型的预测结果更接近实验结果;气液界面边界条件对总体气含率的预测影响较大,采用速度进口或脱气边界和Brucato-Tsuchiya模型耦合计算所得的结果误差比压力出口边界明显要小。

关键词: 侧进式搅拌釜, 气液两相流, 计算流体力学, 边界条件, 曳力模型