双组分聚合物LDPE/PS共挤出过程的三维有限元分析

Three-dimensional Finite Element Analysis of LDPE/PS Coextrusion Processes

采用有限元方法对两种聚合物熔体(LDPE/PS)在共挤出流道内的流动进行了三维数值模拟,分析了两种熔体的入口体积流量比、熔体与模具壁面之间的滑移系数等物理量对于共挤出界面位置和形状的影响。结果表明:随着流量差异的增加,界面位置偏移量增大,同时出口截面上熔体界面曲线的曲率增大;提高流道表面质量可以使熔体速度场趋于均匀,并显著减小界面位置的偏移量。

The three--dimensional flow of non--Newtonian polymer melts （LPDE/PS） in coextrusion dies was analyzed based on finite element simulations. Such simulated results as the interfacial offset and shape and the velocity profile were obtained. It is found that the fluid flux ratio of LDPE to PS notably affects the shape and location of the interface between them, and that the interfacial offset increases with the increase of the fluid flux difference. The simulated results were compared with Gifford＇s results, and then were confirmed. The simulated results also show that the higher surface quality of the fluid path can make the velocity field more uniform and the interfacial offset less.