聚乳酸在啮合同向双螺杆挤出机机头过渡体的流场研究

摘要

Three-dimensional isothermal flow field of polylactic acid(PLA) of the nose transitional body of length to diameter ratio is 44∶1 experiment with a small meshing direction twin-screw extruder head by using the PALYFLOW software.The fields of velocity, pressure, shear rate and viscosity with different process parameters are analyzed and compared.Results showed that the flow field effect become better with the increase of the screw speed and the flow rate at the appropriate temperature,but compared with the increase of the screw speed, the increase of the melt flow was more beneficial to improve mixing and plasticizing effect of the extruder head's transition flow field, and the quality of PLA products.%采用PALYFLOW软件数值模拟聚乳酸(PLA)在长径比为44∶1的试验用小型啮合同向双螺杆挤出机机头过渡体的三维等温流场.在不同的工艺参数下,分析比较了过渡体内的速度场、压力场、剪切速率场和黏度场.结果表明:在适当温度下,增加螺杆转速与增加流量都可以提高流场效果,但与螺杆速度的增加相比,熔体流量的增加更有益于提高整个机头过渡体流场的混合与塑化效果,增加PLA成品的质量.