狭缝初始高度对共挤出吹膜机头的影响  

Influence of Initial Slit Height on Flow Field in Co-Extrusion Blown Film

作　　者：马秀清[1] 翟文斌 程琨[1] MA Xiuqing;ZHAI Wenbin;CHENG Kun(College of Mechanical and Electrical Engineering,Beijing University of Chemical Technology,Beijing 100029 ,China)

机构地区：[1]北京化工大学机电工程学院

出　　处：《塑料》2019年第4期87-90,95,共5页Plastics

摘　　要：共挤出技术可使产品同时具有阻隔性、透明性、印刷性、热封性等特殊性能,并使其成本费用得到大幅度的降低,因而其应用价值得到了越来越广泛的关注。以LDPE/HDPE/LDPE三层共挤出薄膜为例,确定了三层共挤出吹膜机头的流道结构和狭缝流道结构,对三层共挤出吹膜机头的流道进行全六面体网格划分,采用有限元方法对流体在共挤出流道内的等温流动过程进行了求解,分析了狭缝初始高度对机头流道的压力场、速度场以及界面位置的影响。研究表明,随着狭缝初始高度的增大,第一、二和三层的层分配流道压力降减小,共挤出流道压力降变化较小,出口速度分布越来越不均匀;减小狭缝初始高度有利于各层出口速度分布的均匀性,降低界面波动,有利于第一、三层层厚分布的均匀性。Extrusion products with barrier property,transparency,printability,heat sealability and significantly decreased cost could be obtained by co-extrusion technology,therefore co-extrusion technology was being applied more and more broadly.The flow channel and slit channel geometry of three-layer co-extrusion blown film die was built and then meshed with allhexahedral elements whose isothermal flow field numerical simulation in the co-extrusion flow channel was solved by FEM for LDPE/HDPE/LDPE three-layer co-extrusion blown film. The influence of initial slit height on pressure field,velocity field and interface position of the head passage was studied,it showed that as the incipient slit height increased,the pressure dropped in the first,the second and the third layer distribution channel decreased. The pressure drop of the co-extrusion flow path changed little and the velocity distribution at the outlet became more and more uneven. Decreasing the value of incipient slit height could avail velocity distribution uniformity of each layer on outlet surface and thickness distribution uniformity of the first and the third layers and decrease the interface position fluctuation.

关 键 词：多层共挤吹塑薄膜 数值模拟 狭缝初始高度 压力场 速度场 界面位置 

分 类 号：TQ320.52[化学工程—合成树脂塑料工业]