基于两相模型的聚合物流动诱导结晶数值模拟

Numerical simulation of flow-induced crystallization of polymer based on two-phase model

基于两相流动诱导结晶模型,采用谱方法分别计算无定形相的构象张量分布函数和半晶相的取向张量分布函数,进而根据Avrami方程和晶核成核速率与第一法向应力差的关系计算成核速率和结晶度。预测剪切对体系结晶速度的影响,并模拟了活化晶核数目和晶体取向的演化。计算结果表明,剪切对聚合物的结晶动力学性能有显著的影响,但是剪切对聚合物结晶的加速作用不是无限制的,随着剪切强度的增加,对结晶加速作用会变得不再明显。

Based on the two-phase flow-induced crystallization model,according to the Avrami equation and the relationship between the nucleation rate and the first normal stress difference,spectral methods were used to calculate conformation tensor distribution function of amorphous phase and the orientation tensor distribution function of semi-crystalline phase,and then calculate the nucleation rate and crystallinity.The shear impact on crystallization rate of the system was predicted,and the evolution of the number of activation nucleation and crystal orientation was simulated.The results showed that the shearing actions had a significant impact on polymer crystallization kinetics,but the effect of shear on acceleration of polymer crystallization was limited,as the shear intensity increased,the effect on crystallization acceleration became no longer obvious.