组合式双螺杆挤出机中三维等温流动的数值研究

采用有限元软件POLYFLOW,对聚合物熔体在ZSK60组合式啮合同向双螺杆挤出机3种不同构型的组合螺杆中的三维等温流动进行了数值模拟. 分析并比较了组合螺杆的熔体输送特性、速度场和剪切速率场分布规律. 根据拟稳态假设以及双螺杆转动过程的周期性,计算了双螺杆转动180°的流场,在此基础上,采用粒子示踪分析(PTA)方法,对组合螺杆中物料的流动形态和动态混合过程进行了可视化模拟. 模拟结果与前人的实验研究结论一致. 采用数值模拟可以对聚合物熔体在组合螺杆中的复杂流动形态作更为深入的剖析.

Numerical Investigation of 3D Isothermal Flows in Modular Twin-Screw Extruders

Three-dimensional isothermal flows of polymer melt in the screw assemblies of a modular(intermeshing) co-rotating twin-screw extruder ZSK60 are simulated using the finite element package POLYFLOW.Melt pumping characteristics,velocity and shear rate distribution profiles of the screw assemblies are analyzed and discussed.According to the quasi-steady assumption and the rotational(periodicity) of twin screws,flow fields corresponding to the 180°screw rotations are calculated.On this basis,flow patterns and dynamic mixing processes in the screw assemblies are visualized using particle tracking technique(PTA).Numerical results agree with previous experiments.This work presented some methodological suggestions for the numerical simulation of flow in modular twin-screw extruders.It also indicates that,compared with experimental methods,numerical simulation could provide deeper insight into the complex flow patterns of polymer melt in screw assemblies.