螺杆几何参数对强剪切应力挤出机流场的影响

摘要

基于POLYFLOW软件模拟了聚乙烯熔体在等温状态下采用不同螺杆几何参数对挤出机挤出过程的影响，得到了在不同螺杆参数下挤出机流道的压力和剪切速率分布。结果表明，选取三角形的螺棱形状且在螺棱顶端加工2 mm宽的豁口端面能够提高对物料的剪切速率；此外，增加螺棱头数和螺棱升角均可提升剪切速率，从而实现挤出机剪切段的强剪切应力场。%Numerical simulation was used to study the effects of the screw geometric parameters on the extruding performance of extruder.POLYFLOW software was applied to stimulate the process of the isothermal flow fields of PE with different geometric parameters.The pressure fields and the shearing rate fields were obtained.The results show that choosing the triangular shape of screw thread with a fracture of two millimeter will make a stronger shearing rate.In addition,increasing thread number and lead angle will increase shearing rate.Thus,strong shear stress fields of extruder is realized.