微型锥形双螺杆挤出机混合性能的数值模拟  

Numerical Simulation of Mixing Performance in the Miniature Conical Twin Screw Extruder

作　　者：徐俊杰[1] 张先明[1] 陈文兴[1] 冯连芳[2] 

机构地区：[1]浙江理工大学先进纺织材料与制备技术教育部重点实验室,浙江杭州310018 [2]浙江大学化学工程国家重点实验室化学工程与生物工程学系,浙江杭州310027

出　　处：《高分子材料科学与工程》2015年第3期128-132,共5页Polymer Materials Science & Engineering

基　　金：国家自然科学基金资助项目(51103135);浙江省自然科学基金资助项目(Y4100534)

摘　　要：微型锥形双螺杆挤出机(MCTSE)越来越多地应用于新型聚合物纳米复合材料的制备,但对其共混过程的理论研究相对较少。文中首先数值模拟MCTSE挤出聚丙烯(PP)熔体的过程,考察了加工参数和螺杆构型对MCTSE输送能力和沿着轴向平均压力分布的影响。研究表明,螺杆转速和螺距的增加均有利于提高熔体输送能力,沿着螺杆挤出方向,平均压力是先增加后减小。由求解得到速度场的时间积分获得粒子从入口到出口的运动轨迹,统计结果表明,MCTSE的螺杆结构有利于改变剪切或拉伸流动形态,螺杆转速更有利于调控停留时间分布(RTD)。文中采用的数值模拟方法可以点对点分析MCTSE内高聚物熔体沿着轴向流动的分散、分布和轴向混合特征。Miniature conical twin screw extruders(MCTSE) were increasingly applied for preparation of polymer nanocomposites,but limited attention has been paid to theoretical analysis of mixing performance in the MCTSE.In this article,a study was firstly done on the numerical simulation of polypropylene(PP) melt flow in the MCTSE.The effects of screw speed and screw configuration on the conveying capacity of MCTSE and mean pressure distribution along the axial distance were theoretically analyzed.The results show that increasing screw speed or screw pitch can improve the conveying capacity of polymer melt.Along the screw axial direction,the mean pressure increases initially and decreases afterwards.Then a number of particles were randomly distributed in an inlet vertical plane and their trajectories between the inlet and outlet were calculated from the velocity profiles.The statistic results show that the screw configurations of MCTSE are liable to adjust the flow pattern such as shear or extensional flow.Meanwhile,screw speed can change residence time distribution(RTD) obviously.This provides a numerical tool to assess point-by-point information on the dispersing,distributive and axial mixing of polymer melt along the axial distance in the MCTSE.

关 键 词：微型锥形双螺杆挤出机 混合指数 停留时间分布 

分 类 号：TQ320.52[化学工程—合成树脂塑料工业]