needle disc mill;  particle orbital model;  gas-solid two-phase flow;  Numerical simulation

In order to accurately understand the crushing process of the needle-disc mill, the gas phase (RNG) k-ε two-way path model is used, and the particle phase is based on random particle orbital model. The numerical study of gas-solid two-phase flow of needle disc mill was carried out, and the particle orbit model was accurately defined by considering the three influencing factors of particle force, turbulent diffusion and particle size distribution. The simulation results show that under the high-speed impact of the rotor pin rod, a reflux will be formed near the stator area, which is conducive to the re-crushing of particles. The small stator and rotor circumferential clearance and radial clearance are also conducive to the multiple crushing of particles; The angle between the rotor blade and the radial direction is reduced, which is conducive to discharging. This study is helpful for the analysis of the performance of the needle disc mill and the optimization of structure and process parameters.