Structure Optimization of a Two-Dimensional Mixer for Mixing Uniformity Improvement Using the DEM

A two-dimensional (2-D) mixer has been widely used in the engineering field. The discrete element method (DEM) is capable of simulating and tracking collisions among particles inside the mixer. In this paper, the mixing process of spherical particles inside a 2-D mixer known as EYH150L is simulated by the DEM. The Lacey Index provides a quantitative measure of the blending efficacy achieved by a 2-D mixer. The DEM analysis indicated that the level of blending effectiveness among the particles in proximity to the rotating blades is significantly superior to that in regions devoid of blades. The rotational velocities of particles in blade-free zones are about 40% of those near the rotating blades, which serves as a key factor accounting for the slower increase in mixing efficiency observed in these regions. To address this disparity and enhance overall mixing performance, a mirrored rotating blade was incorporated, positioned to the left of the baseline revolving cylinder, thereby optimizing the structural configuration of the 2-D mixer. The verification tests indicated that the modification increases the mixing efficiency of the mixer at its left side, and enhances the blending uniformity, ensuring the four particle types are mixed equitably.