基于离散元法双螺杆挤出机磨损特性分析

Wear characteristics of twin-screw extruder based on discrete element method

双螺杆挤出机在生产过程中经常会出现螺杆磨损等问题,严重影响了螺杆的使用寿命和聚合物加工的品质。本文采用离散单元法(DEM),结合Archard磨损模型,对同向啮合双螺杆挤出机螺杆磨损进行数值模拟,分析螺杆转速和填充率等因素对双螺杆挤出机磨损特性的影响规律。结果表明,螺杆磨损主要发生在螺棱的顶部区域以及进料口处,在物料进入机筒入口处会发生严重的挤压磨损;随着螺杆转速和填充率的增加,螺杆的磨损程度不断增大;料槽后方输送段的螺杆主要产生横向切削磨损,切向累积能量是导致磨损的关键因素。

Twin-screw extruders often have problems such as screw wear in the production process,which seriously affects the service life of the screw and the quality of polymer processing.The screw wear of twin-screw extruder was simulated numerically by using a discrete element method and Archard wear model,and the effect of screw speed and filling rate on the wear characteristics of twin-screw extruder was analyzed.The results indicated that the screw wear mainly occurred in the top area of the screw edge and the inlet of the feed,and serious extrusion wear occurred at the entrance of the material entering the barrel.The wear degree of screw increased continuously with an increase in the screw speed and filling rate.The screw in the rear conveyor section of the feed trough mainly produces transverse cutting wear,and the tangential accumulated energy is the key factor which leads to wear.