中文摘要：

以挤出圆管为研究对象，采用PTT、粘弹本构模型和通用的有限元POLYFLOW软件，对塑料熔体在不同挤出口模内的二维粘弹性等温流动进行了数值模拟。通过数值模拟得出了CPU时间、压力和离模膨胀比等结果。研究表明，过渡段的设计会对挤出压力产生明显的影响，但对离模膨胀比没有影响，用三次插值多项式表征的流线型口模具有较小的挤出压力。

英文摘要：

The numerical simulation used POLYFLOW software was implemented for the two dimensional isothermal PTT polymer melt flow within an extrusion die with circle. Especially, the CPU times and power distributions and die swell ratio were analyzed in details. The analysis shows that the transition zone of the die plays a significant role on power distributions, but has no influence on dies swell ratio. Polymer melts flow through streamlined extrusion die with third order polynomial equation has the least power.