环形片材机头流道三维非等温流动的数值模拟

Numerical Simulation of Three Dimensional Non-isothermal Flow of Ring Die

利用前期流变实验所获得的PP/CO_2粘度数据,对纯PP本构方程的各项参数进行修正。通过有限元软件Polyflow分析了含有发泡剂时聚丙烯在环形片材机头流道中的流动特性。模拟结果表明:流道压力场随着口模间隙、流道外壁温度和注气量的增大以及进料量的减小呈规律性的降低;口模间隙对压力场影响最大,口模间隙过大(>4 mm),流道即会出现过早的预发泡;注气量、进料量和口模间隙的变化基本不影响流道温度场。

Using PP/CO2 material data gained from rheological experiments before, parameters about polypropylene in constitutive equation are amended. Through FEM software Polyflow, flow inside runner of ring runner is analyzed. Simulation results show that with outlet, die temperature and the mass fraction of CO2 increase, or with inflow decreases, pressure field will reduce regulary. Outlet is of the greatest importance to pressure field. If outlet is widder than dram, phase seperation will be happened. The change of the mass fraction of CO2 and inflow will basically not influence temperature field inside runner.