Discrete element simulation on mixing of granular materials in rotated container

Mixing of granular materials is a very important process for various industries, such as food, pharmaceutical, chemical, ceramic and construction industries. In this study, the discrete element simulation software PFC2D was used to simulate mixing process. A quantifiable calculation method was suggested to determine the time of homogenous mixing. In this method, the predefined particles distribution in simulated area is recorded along with the time to describe the mixing performance. Based on simulation data, the mixing time under different particle size, stiffness, density and drum rotational speed were calculated. The results show that particle stiffness and density have slight influence on the mixing process; with the increase of particle radius ratio, the mixing process is obviously accelerated; the middle size particles has a significant effect on the mixing speed. Increasing the rotational speed can accelerate the mixing process, but when rotational speed is high enough, the increased rotational speed has slight contribution to accelerate the mixing process.