Abstract
高分子在押出加工程序中,產品深受成形模幾何設計和加工條件的影響.複雜的成形模可經由其設計上的特性和潤滑近似原理的應用,因此往往可減化成一維或二維流動,但是欲正確獲取高分子流體在實際成形模頭內流動情形,及複雜模具幾何形狀對流場的影響,皆需由三維流動模擬分析,才能得到這些資訊.由於有限元素法有處裡不規則幾何形狀上的特性,因此本文使用三維有限元素法來模擬高分子在押出模頭內流動情形.在本文的研究討論共分三部份,第一部份使用三維有限元素法,探討高分子在入口效應之影響,進而討論忽略入口效應的一維及二維模擬其幾何限制及適用範圍,第二部份則針對實際工廠押出模具設計,進行三維模擬分析,檢視模具設計其出口厚度分佈及所需壓降.第三部份我們將探討在非恆溫模擬中,葛拉金有限元素法和sub-element,及SUPG三種方法在移流-擴散問題其處裡能力,及適用性.The flow of polymer melt in extrusion dies of complexgeometries,such as profile die,film die ...etc,cannot beeasily analyzed to account for complex rheology and complexgeometry. In most application, polymer melt flows in a shell-like layer. It allows us to utilize some approximations:hydrodynamic lubrication approximation and confined flowapproximation. Consequently we could simplify the threedimensional flow as either unidirectional or bi-directionalflow. It could be understood that the physical process based onsimplified geometry will take less computational time. Foraccurate modeling the polymer processing operation it isnecessary to represent these shapes accurately.A generalpurpose three-dimensional FEM program has been developed foranalysing the industrial flow process domainated by the non-linear viscous phenomena.This program is designed particularlyfor polymer and rubber processing. To see the magitude of theerror, the entrance effect is first considered in the squrechanel test by a three dimensional FEM simulation. Forreforcing this program capibility, the Galerkin,2×2 sub-element,and SUPG have been discussed in the non-isothermal highPeclect number flow. Finally, The most important subject inthis study is to see the uniformity of the extrusion die. Theresults through this program show excellent agreement withother study such as POLY-FLOW package, etc.