中文摘要：

本文采用数值计算方法分析了挤出机不同螺杆塑化系统的流动与传热特性,并且提出了一种新型螺杆元件——扭转元件。结果表明,相对于普通螺纹元件,配置有扭转元件的螺杆具有更好的温度均匀性和传热性能。扭转元件中非牛顿黏弹性流体的强化传热的机理可以用场协同理论进行解释,即扭转元件的温度梯度场与速度场的协同性更好,努塞尔数更高,对流换热性能更好。

英文摘要：

3-D numerical simulations are performed for heat transfer and fluid flow characteristics of the extruder plasticizing unit fitted with various screws.New screw element with twisted groove,called torsion element,is proposed for the first time.The simulation results reveal that screws with torsion elements have better temperature uniformity and heat transfer performance than the conventional ones without torsion element.The mechanism of heat transfer enhancement by the torsion element is also analyzed from the viewpoint of field synergy principle.Decreasing the mean intersection angle between the temperature gradient and the velocity vector increases the Nusselt number;hence the higher coefficient of local heat transfer,and consequently leads to the improvement of heat transfer performance in overall.