摘要
采用PTT本构方程和Arrhenius黏度对温度依赖方程,运用有限元方法,对低密聚乙烯(LDPE)/高密聚乙烯(HDPE)熔体的共挤过程进行了三维非等温粘弹数值模拟,对比分析了两熔体在传统和气辅共挤过程中的速度场、剪切速率分布和层间界面形貌。研究表明,气辅共挤成型在口模出口处不存在二次流动,且在挤出方向流速均匀,剪切速率分布均匀且数值比传统共挤小得多,说明气辅共挤能有效消除传统共挤过程中的挤出胀大和界面偏移现象。
A three-dimensional non-isothermal viscoelastic numerical model was established with PTT constitutive equation by the finite element method. The temperature-dependent transport properties were expressed by the Arrhenius equation. The coextrusion processes of LDPE and HDPE were simulated and the velocity field, shear rate distribution and the interface pattern were compared and analyzed. The research results show that the die swell and the interface deflection phenomenon in traditional coextrusion process can be eliminated in gas-assisted coextrusion process. For the gas-assisted coextrusion process, there isn＇t the secondary flow at the die exit and the flow rate is uniform along the direction of coextrusion, the shear rate distribution is uniform and the value is much smaller than one of conventional coextrusion process.
出处
《高分子材料科学与工程》
EI
CAS
CSCD
北大核心
2013年第3期169-172,共4页
Polymer Materials Science & Engineering
基金
国家自然科学基金资助项目(51163011)
高等学校博士学科点专项科研基金(20093601110001)
赣鄱英才555工程领军人物培养计划项目资助
关键词
气辅共挤
非等温
粘弹流动
挤出胀大
数值模拟
gas-assisted coextrusion
nonisothermal
viscoelastic flow
die swell
numerical simulation
