注射螺杆流道熔体非等温流场的数值研究

使用CFD软件Polyflow,数值模拟了注塑机塑化和注射过程中两种止逆螺杆流道内聚丙烯熔体的三维非等温流场,讨论了流道内熔体的温度场、剪切速率场、黏度场和黏性热场.研究结果表明,塑化时,35°锥角比60°锥角螺杆流道内的熔体在螺杆头区域的温度高;注射时,35°锥角较60°锥角螺杆流道内熔体在出口处的温度和黏度都均匀.表明35°锥角螺杆与机筒配合得较好,更利于注塑成型.数值计算对比了60°锥角螺杆流道内熔体的非等温和等温流场,在螺杆头某一截面上非等温时熔体的平均黏度值比等温时的减少24%.温度影响熔体流场中各物理量的变化.非等温流场更能反映实际情况.

Simulation of Nonisothermal Flow Field of Melt in Injecting Screw

The 3-D nonisothermal flow field of polypropylene melt in two non-return injection screws was simulated in plasticizing and injecting phase by using the CFD package Polyflow.The field of temperature,shear rate,viscosity and viscosity heating of melt in two phases were analyzed in this paper.Simulation results indicate that the temperature of melt in the zone of 35° cone screw head is higher than that of 60° cone in plasticizing phase.The temperature and viscosity of melt in 35° cone screw is more even at the exit in injecting phase.35° cone screw is better in injection,since the 35° cone screw matches the barrel better.Compared the nonisothermal flow field with the isothermal one in the zone of 60° cone,the average melt viscosity in some section decreased 24%.The temperature influences all melt physical parameters in the flow field.The nonisothermal flow field is close to the fact.