聚合物熔体在异型材三维动态挤出口模内的停留时间分布  

Residence Time Distribution of Polymer Melt within Three-dimensional Dynamic Extrusion Dies of Profile

作　　者：吴晓[1] 柳和生[2] 

机构地区：[1]武汉科技学院机电工程系,湖北武汉430074 [2]南昌大学机电工程学院,江苏南昌330029

出　　处：《中国塑料》2004年第4期94-97,共4页China Plastics

基　　金：国家自然科学基金 ( 5 9763 0 0 2 );江西省自然科学基金( 0 15 0 0 13 )资助

摘　　要：利用ANSYS软件对受口模入口处周期性振动的压力驱动的聚合物熔体在“Y”形和“L”形异型材挤出口模内的停留时间分布进行了数值模拟。设熔体流动为三维等温广义牛顿幂律流动 ,在求得速度场后 ,应用路线示踪法跟踪流场中任一粒子的流动轨迹 ,进而求得熔体在口模中的停留时间分布。通过改变振动参数再重复计算 ,总结出振动参数对停留时间分布的影响规律。结果表明 :压力的振动能有效地缩短熔体在口模内的停留时间 ,振幅和频率越高则停留时间越短 ,而且在靠近口模流道壁面处停留时间的缩短最明显 ,表明振动的引入可以降低壁面附近的流动阻力 ,使截面上的流速更平稳 ,从而改善挤出制品的表观质量。The residence time profile of the polymer melt,which was driven by a periodically oscillating entrance pressure,in an extrusion die of “Y' or “L' shaped cross section was simulated using ANSYS software package.The melt flow was treated as the three dimensional isothermal generalized Newtonian power-law flow.After computation of the velocity field the residence time profile of melt within the die was computed by means of the path line tracking method under various sets of oscillation parameters.Thereafter,the effect of the oscillation parameters on the residence time profile was outlined as follows.The oscillation of entrance pressure can substantively decrease the residence time of the melt,and the higher the amplitude or the frequency,the shorter the residence time.The largest decrease of residence time occurred near the wall of the die channel.This means that the oscillation can reduce the flow resistance near the wall of the die channel,increase the uniformity of the velocity across the cross section of the die and thus improve the apparent quality of the extrusion products.

关 键 词：停留时间分布 挤出 口模 异型材 

分 类 号：TQ320.663[化学工程—合成树脂塑料工业]