以PTT黏彈模式對共押出進料區塊進行三維有限元素模擬

Abstract

以PTT黏彈模式對共押出進料區塊進行三維有限元素模擬

學生：羅順鴻

指導教授：許千樹教授 吳建興副教授

國立交通大學應用化學研究所碩士班

摘 要 本文旨在使用Phan-Thien and Tanner黏彈模型進行雙層共押出進料區塊內流動之三維有限元素模擬，探討共押出製程中之界面包覆，並在進料區塊壁面邊界採取滑動邊界設定。由模擬結果可看出，相對於不滑動邊界，滑動邊界設定使壁面接觸線可在壁面上移動，能有效預測流體界面彎曲變化情形，且不會忽略壁面之影響。本文藉由改變PTT黏彈模型中之ξ參數探討因第二正向應力差對界面的影響，可明顯看出第二正向應力差對於界面包覆現象之影響極大。同時也藉由改變PTT黏彈模型中之ε參數探討因伸展黏度對界面的影響，雖然不及第二正向應力差對界面的影響，但仍不能忽視其作用。本文可觀察到第二正向應力差的差值會對界面的形狀造成影響。

Three-Dimensional Flow simulation of coextrusion Feedblock with PTT viscoelastic model

Student：SHUN-HONG LUO

Advisor：Professor Chain-Shu Hsu Professor Jiann-Shing Wu

Institute of Applied Chemistry National Chiao Tung University

Abstract In this study, the 3D finite element simulation of bicomponent coextrusion feedblock with Phan-Thien and Tanner viscoelastic model and slip boundary condition impose at the polymer/polymer/wall contact line were discussed. Results show that in contrast to no-slip boundary conditions, slip boundary conditions would allow displacement of the contact line along the wall and have a more precise predicition of interface distortion without discarding wall effects. The development of secondary flow due to the second normal stress difference is analyzed by varying the parameter ξ in the Phan-Thien and Tanner model,and it is obvious that the second normal stress difference have an great influence on the encapsulation phenomena. We also discuss the development of interface shape by changing the parameter ε which is concern in extensional viscosity ,although it has less influence compaing with the parameter ξ on development of interface shape . This study shows that the difference of N2 (DN2) has influence on the development of interface shape.