中文摘要：

采用参数渐变法和Thompson变换,对粘弹性高分子熔体在不同气体辅助挤出口模内的流动进行了数值模拟研究。考察了体积流量、松弛时间和滑移段长度对挤出物挤出胀大比的影响。研究表明,熔体在滑移段的停留时间与材料松弛时间之比与挤出胀大比之间存在指数衰减关系,其实质是熔体在滑移段处于形变衰减过程。理论分析与数值模拟具有高度的一致性,表明该方程可用于指导气辅口模设计。

英文摘要：

Based on the evolution and thompson transformation, a numerical simulation system describing the flowing visco-elastic polymer passing through different gas-assisted extrusion （GAE） dies was established. The effects of shear rate, relaxation time and slip length on extrudate swell ratio were investigated using simulation. The results show that the die swell ratio is exponentially decreasing in rdation to the ratio of the residence time in slip part to material＇s relaxation time, which essence is that molten polymer in slip part be in deformation attenuation process. Theoretical analysis and numerical simulation have a high degree of consistency, it is note that the equation can be used to guide the design of gas-assisted extrudate die..