Abstract:The study of solid-liquid mixing characteristics is of great significance to the optimization of production efficiency, energy consumption and other indicators, and the vertical mixing kettle is more often used in actual production. In this paper, we use the CFD method and the DEM method to carry out numerical simulation research on the particle mixing characteristics of the vertical mixing kettle in terms of the particle density, particle size, mixing speed and the initial liquid level height, etc., and evaluate the particle mixing characteristics in terms of three dimensions, namely the velocity field, turbulent kinetic energy distribution and the degree of mixing of the particles. The mixing characteristics of particles were judged from three dimensions: velocity field, turbulence energy distribution and particle mixing degree. The results show that, among these factors, the particle density and stirring speed have the greatest influence on the mixing characteristics, especially when the particle density is 1200kg/m3, the relative standard deviation value reaches about 0.5, which indicates that the mixing degree is better; the larger the stirring speed is, the better the mixing performance is; the particle size has less influence on the mixing performance, but the smaller the particle size is, the more easy it is to be suspended, and the increase of the particle size decreases the mixing degree; the change of initial liquid surface height leads to the change of solid content rate, but it has no effect on the solid-liquid mixing performance.