Electromechanical coupling characteristics analysis of vertical stirred mill based on ECS-MBD-DEM

Abstract

This paper focuses on the start-up and steady-state operation stages of a vertical stirred mill, and the electromechanical coupling characteristics are thoroughly investigated based on the ECS-MBD-DEM coupling method. Firstly, according to the driving and working principles of the vertical stirred mill, the electrical control system (ECS) and multibody dynamics (MBD) model of the vertical stirred mill are separately established. Subsequently, a discrete element method (DEM) model is developed for the grinding media inside the mill. On this basis, the ECS-MBD-DEM coupling model of the vertical stirred mill is constructed, and its feasibility is validated through experiments. Then, the pitch, screw diameter, grinding media filling, and mill rotation speed of the helical agitator are considered as influential factors, with average value and coefficient of variation used as evaluation indicators for the level and fluctuation of changes. The load torque and current amplitude during the start-up and steady-state stages of the vertical stirred mill are analysed separately based on the ECS-MBD-DEM coupling method. The results indicate that the pitch, screw diameter, and grinding media filling have a significant effect on the average value of load torque. The screw diameter, grinding media filling, and mill rotation speed significantly influence the coefficient of variation of the load torque. The mill speed has a significant effect on the average value and coefficient of variation of the current amplitude. Finally, the cumulative volume velocity difference is proposed as an evaluation indicator for the grinding efficiency in the annular region, and the impact of influential factors on it is discussed, the results show that the grinding media filling and mill speed have a significant impact on the cumulative volume velocity difference.