物性参数对三层共挤出机头流道流场的影响

Influence of Materials Physical Parameters on Flow Field in Three-Layer Coextrusion Die Flow Channel

以PP/RPP/PP三层共挤出板材为例,采用有限元方法对非牛顿流体在共挤出流道内的等温流动过程进行了三维数值模拟。重点分析了三层复合共挤出板材机头流道中每层物料黏度比和松弛时间比对出口界面位置偏移的影响。数值模拟分析结果表明:随着物料黏度比的增大,出口界面越来越稳定。熔体层间物料黏度差异越小,界面位置越接近理想界面。随着物料松弛时间比的增大,出口界面越来越稳定;熔体层间物料松弛时间差异越小,界面位置越接近理想界面位置。

The three-dimensional numerical simulation of Non-Newtonian fluid isothermal flow process in coextrusion flow channel was studied by FEM in a case study of PP/RPP/PP three-layer composite coextrusion sheet. The influence that viscosity ratio and relaxation time ratio of each layer material had on exit interface position deviation was analyzed intensively in the flow channel of three-layer composite coextrusion sheet die. The results showed that the exit interface became more and more stable. The interface position were approaching to the ideal interface when the viscosity difference of adjacent layers became smaller. With the increase of material relaxation time rate, the exit interface position more and more stable. The interface position were approached to the ideal interface when the relaxation time difference of adjacent layers became smaller.