三层共挤吹膜机头流道流场的数值模拟  

Numerical Simulation of Three-Layer Coextrusion Blown Film

作　　者：焦志伟[1] 王立胜 张义成 张长坤 杨卫民[1] JIAO Zhiwei;WANG Lisheng;ZHANG Yicheng;ZHANG Changkun;YANG Weimin(College of Mechanical and Electrical Engineering,Beijing University of Chemical Technology,Beijing 100029,China;Shandong Hengrun Banghe Machinery Manufacturing Co.,Ltd.,Jinan,Shandong 271100,China)

机构地区：[1]北京化工大学,机电工程学院,北京100029 [2]山东恒润邦和机械制造有限公司,山东济南271100

出　　处：《塑料》2020年第5期116-120,共5页Plastics

摘　　要：多层共挤吹膜机头被广泛应用于复合薄膜加工领域,具有设备简单、成本低廉、产品质量优良等优点。以LDPE/HDPE/LDPE三层复合薄膜为例,将实际使用的一种三层共挤吹膜机头作为模具,利用软件Polyflow对熔体在机头流道内的等温流动过程进行求解,并分析了流道内的压力场、速度场、层与层之间的界面位置。研究结果表明,在层分配流道中熔体流动的方向,由沿螺旋槽的周向流动逐渐过渡为沿挤出方向的轴向流动;在各层分配流道汇入共挤出流道的位置处的速度场发生了改变,即出现了“次流动”;在口模出口端面位置处,熔体各层之间的界面发生了偏移,界面1和界面2均有向中间层熔体偏移的趋势。With the advantages of simple equipment,low cost and excellent product quality,the multi-layer co-extrusion blown film heads were widely applied in the field of the composite film processing. Taking the three-layer composite film of LDPE/HDPE/LDPE for an example,a three-layer co-extrusion blown film head used as the mold in practice,the isothermal flow process of the melt in the flow path of the head was solved by the special analysis software polyflow,the pressure field in the flow channel,the velocity field and the position of the layer-to-layer interface were analyzed at the sametime. The results show that the direction of melt flow in the layer distribution channel gradually changed from the circumferential flow along the spiral groove to the axial flow along the extrusion direction;the velocity at the position where the distribution channels of each layer join the co-extrusion channel has changed,which meaned that there was a"secondary flow";at the exit end face of the die,the interface between the layers of the melt were shifted,and both interface 1 and interface 2 have the tendency to shift toward the intermediate layer.

关 键 词：吹膜机头 流道流场 POLYFLOW 复合薄膜 界面位置 

分 类 号：TP391.7[自动化与计算机技术—计算机应用技术]