螺带螺杆搅拌釜中高黏流体的CFD模拟计算

CFD Prediction of Stirred Tank with Double Helical Ribbon and Helical Screw Ribbon Impellers

高黏聚合体系的搅拌混合应用广泛,是聚合物合成工业中的关键,但采用实验方法难以得到其流场。应用ANSYS CFX软件模拟计算高黏聚苯乙烯溶液体系在不同螺带螺杆组合搅拌釜中的流场特征,分别采用不同的计算流场模型进行求解,其中搅拌釜气-液两相界面采用与实际情况较为接近的自由液面,旋转区域采用滑移网格法处理,液相采用不同黏度的高分子黏性流体,计算比较了不同搅拌桨组合下的流场特征,论证了双螺带螺杆搅拌桨在高黏流体混合中的优越性,同时得到不同黏度和不同转速下搅拌釜内的液面形状、速度场和搅拌功率,为实际生产及工业优化提供了理论参考。

The flow field characteristic of high viscosity polystyrene solution in stirred tank with different helical ribbon and helical screw ribbon assemble impellers were calculated by commercial CFD code ANSYS CFX. Different models for flow field calculation were employed in the simulation. Among them, a free liquid surface model for the gas-liquid surface in the stirred tank, which is close to reality operation condition, was used. The sliding grids method was employed to deal with the rotating reference frame for impeller area. The liquid phases were the polymer solutions with different viscosities. The flow fields with various combination of impellers were compared. The outstanding performance of double helical ribbon and screw ribbon impellers in high viscosity liquid was confirmed. The shape of liquid surface, the velocity field and the power consumption of stirring were calculated, which are valueable for industrial operation and optimization.