Discrete element simulation for mixing performances and power consumption in a twin-blade planetary mixer with non-cohesive particles

Abstract

The present study aims to characterize the mixing performances and power consumption of a twin-blade planetary mixer with non-cohesive particles through the discrete element method (DEM). A DEM model used for simulating the particle flow and mixing kinetics of the mixer was experimentally verified. The particle velocity and mixing mechanism are elaborated quantitatively, indicating that particle mixing is realized under the combined actions of radial, circumferential and vertical circulations, and some local collisions and mergers. Increasing the absolute speed N and the speed ratio i promotes the radial circulation, while the tangential and vertical circulations are strengthened with the increase of N and the decrease of i. The mixing time required for the homogeneous state decreases, and the power consumption increases as N increases and i decreases. Thus, increasing N and decreasing i can improve the mixing performance but require more energy to reach the homogeneous state. Also, the mixing performance shows a strong correlation with the swept volume of blades, which proves that the dominant mixing mechanism of the mixer is convection.