中空纖維黏合機制及其模具設計之探討

The study of gluing mechanism and die design for hollow fiber

申博元(Bo-Yuan Shen)

指導教授 ： 蘇淵源

國立臺北科技大學/工程學院/化學工程所/碩士(2005年)

https://doi.org/10.6841/NTUT.2005.00156

摘要

本研究使用有限元素法搭配optimesh-3D remeshing及EVSS/SU之數值技巧解決模擬中空纖維紡絲時所遭遇之自由表面及微分型Phan-Thien-Tanner (PTT)材料本質方程式(constitutive equation)之非線性問題。
首先，我們針對不同幾何形狀(4C型、C型)模具、相異特性材料(Nylon6、PP)、及操作條件等對中空纖維出模口後黏合機制的影響作深入探討，並就模擬所得之黏合長度與實驗結果作比較，找出決定黏合機制之主因及最大臨界裂縫寬度，藉此做為製作中空纖維之依據。此外，再利用應力分析來建立擠出物三維模口膨脹與黏合機制之關聯性。從其結果中我們發現就牛頓流體而言，黏度及慣性效應對黏合長度並無明顯之影響。然而對於高分子而言，控制黏合長度之主要材料特性有拉伸效應、彈性效應及高分子黏彈特性表徵等，因此本研究即針對材料參數對黏合機制之影響作深入探討，以便做為預測中空纖維黏合機制之參考。
最後利用逆向模口設計技巧，由預定之中空纖維形狀與尺寸反推模口之幾何形狀大小，以瞭解材料性質與操作條件對模具設計之影響。從其結果中我們發現影響設計紡嘴之截面積最主要因素為黏度，黏度越小，所需紡嘴面積越大，因此黏度效應為設計紡嘴之參考基準。

關鍵字

中空纖維 ； 有限元素法 ； 模口膨脹 ； 模口設計

並列摘要

This research utilized the numerical approach of finite element method with optimesh-3D remeshing and EVSS/SU techniques to solve the non-linearity problem encountered in both free surface and Phan-Thien-Tanner (PTT) material-based differential constitutive equation while simulating hollow fiber extrusion.
First, we investigated the effect of different geometric-shaped dies (4C type and C type), materials (Nylon6 and PP) and operational conditions on the gluing mechanism of hollow fiber extrudate. And the fissure lengths from simulation data are compared with those of the experimental results to determine gluing mechanism for manufacturing guide. With tensor analysis we established a the co-relation between three-dimensional die swell and the gluing mechanism of extrudate. It appears that viscosity and inertia had little influence on the fissure length for Newtonian fluid. However, for polymeric material, it is known elongation and relax time properties exhibit a great effect on the fissure length, so we have made a in-depth analysis of material property effect on the gluing mechanism.
Finally we used inverse die design, based on the desired shape and size of hollow fiber, to infer the appropriate geometric shape and size of the die. Thus we can understand the effect of material property and different operational conditions on the design of die. From the results, we have found out that the major factor affecting the section area of die is viscosity. The lower viscosity, the larger die needed. Viscosity could be the basic variable for specific die design.

並列關鍵字

Hollow Fiber ； FEM ； Contraction Flow ； Die Design ； Die swell

參考文獻

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