螺旋芯棒式吹膜模头熔体流动特性的数值模拟

对吹塑薄膜螺旋芯棒式模头内熔体的流动现象进行了三维数值模拟。结果表明，随着螺槽的逐渐消退，螺槽内熔体的速度由入口处的沿螺槽方向流动逐渐变为沿模头轴向流动，而环形间隙内熔体的速度在入口处存在较小的环形分量，随间隙厚度的增加逐渐变为沿轴向流动。沿挤出方向，螺槽中熔体的压力等值线由垂直于螺槽逐渐变为垂直于轴向，环形间隙中熔体的压力等值线由倾斜于轴向逐渐变为垂直于轴向。

Numerical Simulation on Melt Flow Characteristic in Spiral Mandrel Die for Blown Film

The melt flow phenomenon in spiral mandrel die has been studied with 3D numerical simulation. The results showed that the melt in spiral groove flows from mainly along spiral direction to mandrel axial direction as the spiral groove runout, meanwhile, the melt in annulus clearance flows mainly along mandrel axial direction, although there exists a small circumferential velocity in the initial area, it gradually disappears as increase of clearance thickness. Along extrusion direction, the isobar in groove becomes to perpendicular to mandrel axis from perpendicular to groove, while the isobar in annulus clearance becomes to perpendicular to mandrel axis from inclining to mandrel axis.