单个聚合物颗粒在剪切流场中熔融模型的建立

Establishment of Single Polymer Pellet Melting Process Model under Shear Flow

采用FLUENT的VOF界面追踪方法模拟了聚合物颗粒在简单剪切流场下的变形、熔融和流动行为。利用聚丙烯(PP)颗粒在高密度聚乙烯(HDPE)熔体中的动态可视化实验进行验证,初步探讨了简单剪切流场下聚合物颗粒的熔融机理。从理论上建立了单个聚合物粒子在剪切流场中的熔融模型,得到了熔融时间与剪切速率之间的关系,对后续聚合物成型加工研究具有指导意义。

Polypropylene （PP） pellet melting mechanism in PE melt under shear flow were investigated using visualization method and numerical simulations. The volume of fluid （VOF） method in FLUENT was used to track the dynamic interface. Erosion mechanism similar to that observed in the visualization experiment appeared in the simulations. From the simulation results, It was found that the shear stress and shear rate at the interface was much higher than these in the matrix phase, which could explain the erosion breakup mechanism. Meanwhile, a theoretical model about single polymer pellet melting process under shear flow wes established, obtained the relationship between the melting time and shear rate. It was instructive to the following polymer processing research.