基于注塑成型过程的液晶高分子Hele-Shaw流动模拟分析

Numerical analysis of the liquid crystalline backflow-driven effect under a continuous square wave electric field

针对注射模腔内液晶高分子Hele-Shaw流动进行模拟分析。模腔为规则的方形,温度为恒温300℃,以小分子液晶TIF理论为基础,建立内部流动分析方程组;采用这种方法预测整个注塑过程中任意时间点流动前沿的位置,随时掌握腔内压力、速度场的变化情况。通过模拟分析得知:在入射口处压力、速度场分布变化最大,向内部逐渐减小,且分布均匀,无畸变点;向矢场的变化则与模腔高度有关,靠近腔壁处分子向矢按照流动方向均匀排列,而中心层相对复杂,由X-Y平面内流动剪切速率决定;注射时间与初始压力、模腔高度的平方成反比。本文的结果为进一步分析注塑过程中非恒温下液晶高分子流动提供了参考。

In order to broaden the application range of LCP(Liquid Crystal Polymer), the simulation of the LCP Hele-Shaw flow in the square cavity is conducted. The temperature of the cavity is kept at constant 300℃. In the simulation the Leslie-Ericksen and TIF(Transversely Isotropic Fluid) theories are used. With this simulation results, we can predict the position of the flow front at any time during the whole injection process and know well the change of the pressure field and the velocity field. The change of the pressure and the velocity fields are very slow, there is no distortion point in the whole flow field. In the layer near the wall, the directors are arranged evenly according to the direction of the flow and in the center layer it is placed via the shear rate in the X-Y plane. The injection time is inversely proportional to the initial injection pressure and the square of the cavity height. The results of this paper lay the foundation for the analysis of the non-constant temperature LCP flow.