聚合物熔体在不同挤出口模内流动的数值模拟研究

构建了3种构型的圆棒挤出口模，采用有限元分析软件POLYFLOW对聚合物熔体在挤出口模中的二维等温流动进行了数值模拟，分析了熔体在不同口模内的速度和压力分布。结果表明，直线形口模在入口处易产生局部环流，而喇叭形和流线形口模可有效消除局部二次流动。在相同条件下，喇叭形口模在出口处存在较大的挤出负压，为-172．9MPa，而流线形口模为-43．72MPa，两者相比，后者压力降低了75％。因此流线形口模在3种几何构型中结构最为合理。

Numerical Simulation of Polymer Flow in Different Extrusion Dies

Using program POLYFLOW, numerical simulation was implemented for the two dimensional isothermal polymer melt flow through the extrusion die with three types of stick. The distributions of velocity and pressure under various extrusion dies were worked out. Analysis and comparison show that for the shear die, the local circumfluence existed near its entrance, while for the bell-mouthed and the streamlined die, the local circumfluence disappeared. Subtractive pressure at the outlet of the bell- mouthed die was - 172.9 MPa, while it was - 43.72 MPa of the streamlined die. Contrast to the former, the extrusion pressure reduced 75 % of the streamlined die. And finally, the optimum structural design of the extrusion die was the streamlined die.