摘要：采用离散单元法 (DEM) 对机械式高速混合机内部4种不同粒径亚克力球形颗粒组成的颗粒群的运动混合过程进行数值模拟, 分析颗粒混合特性。结果表明, 快速混合区域主要集中在混合机中下部, 混合机内部颗粒在搅拌桨作用下呈现连续螺旋上下运动状态, 中心形成漩涡, 高速飞刀有效地防止颗粒团聚;高速混合机的特殊结构以及大小颗粒各异的流动行为, 导致颗粒在静止过程中边缘出现少量小颗粒偏析现象;颗粒受力与速度随着高度的增加逐渐减小, 并且越高层颗粒受力与速度降低越慢, 颗粒尺寸越大颗粒受力与颗粒速度越大, 高速旋转的颗粒受到较大离心力作用, 使得颗粒法向力大于切向力, 颗粒尺寸越大, 法向力与切向力差距越大。

关键词：机械式高速混合机；离散单元法；多粒径颗粒；颗粒运动；颗粒受力

Abstract：The discrete element method (DEM) was employed to simulate the motion and mixing of internal particle group composed of four different diameters acrylic particles in a mechanical high speed mixer. Analysis of the characteristics of particle mixing shows that the rapid mixing zone is mainly distributed in the middle and lower part of the mixer. Under the action of the agitator blade, the internal particles under a continuous spiral up and down condition. Besides, it forms a whirlpool in the center of the vessel. The high speed chopper prevents the particles from gathering together effectively. The special structure of high speed mixer and the flow behavior of different sizes particles lead to the phenomenon of small particle segregation occurs at the edge of the stationary process. The force and velocity of the particles decrease gradually with the increase of the height, and the decrease of particle force and velocity slow down with the increased height. The greater the particle size is, the higher particle force and velocity are. High-speed rotating particles are subjected to greater centrifugal force and it makes the normal force higher than the tangential force. The greater disparity between normal force and tangential force with the increase of particle size.

Keywords： mechanical high speed mixer；discrete element method；polydisperse particles；particle motion；particle force