衣架式流延模头内熔体流动与模具变形的三维耦合数值模拟

利用Polyflow软件对一种衣架式流延模头内熔体的流动和模具变形进行了三维耦合数值模拟。结果表明:衣架式模头中熔体的流动可视为歧管内(沿歧管方向)和狭缝中(沿挤出方向)的压力流的组合;模头狭缝表面在模具厚度方向的变形沿挤出方向近似为线性增加,而沿模具宽度方向为非线性减小;模具变形后的熔体出口流率由狭缝的实际间隙和扇形区出口处的压力共同决定,单位宽度的出口流率沿模具宽度方向先增加后减小。

3-D Coupling Numerical Simulation on Melt Flow and Die Deformation in Coat-hanger Casting Die

Three-dimensional(3-D) coupling numerical simulation was carried out on the melt flow field and die deformation in a coat-hanger die by means of Polyflow software.The results show that flow state of the melt in coat-hanger die can be considered as the combination of pressure flow along die width direction in manifold and pressure flow along extrusion direction in slit.The die deformation of slit in the thickness direction shows approximately linear increase along extrusion direction,and decreases nonlinearly along die width direction;While considering die deformation,the actual slit width and preland outlet pressure along die width direction codetermine the melt exit flow rate uniformity,and exit flow rate increases first and then decreases along die width direction.