同向双螺杆挤出机下落机头的流道设计

Runner design of drop head of co-rotating twin screw extruder

使用POLYFLOW软件,分别数值模拟了同向双螺杆挤出机机头流道内PP熔体的流动过程,数值计算了机头流道内熔体的压力场、速度场、剪切速率场和黏度场,采用例子示踪法统计分析了流道内PP熔体的流动过程。研究结果表明,由于原始机头流道设计不合理,机头出口处熔体分布不均匀,表现为中心孔速度大,两边孔速度小。改进后的机头较好地克服了这一问题,机头出口处熔体流动较均匀,能保证挤出制品的质量。

In this paper,the flow process of PP melt in the head runner of co-rotating twin-screw extruder was numerically simulated by using POLYFLOW software.The pressure field,velocity field,shear rate field and viscosity field of the melt in the head runner were numerically calculated.The flow process of PP melt in the runner was statistically analyzed by using the example tracing method.The results showed that due to the unreasonable design of the original head runner,the melt distribution at the exit of the head is not uniform,which shows that the velocity of the central hole is large and that of the two sides is small.The improved head overcomes this problem.The melt flow at the exit of the head is more uniform,which can ensure the quality of the extruded products.