Applications of the discrete element method in heat transfer mechanisms of powders: Stirred milling

Abstract

Mechanical ball milling has been identified as one of the crucial steps in the preparation of component bulk materials. Due to the self-heating of certain materials, the temperature has a significant effect on their performance. Therefore, it is very important to understand the temperature distribution of the powder particles during mechanical ball milling. In this work, to reduce the adhesion between particles and the mill, a "7" type stirred ball mill model was designed using the Discrete Element Method (DEM), and the heat transfer mechanism of powder particles was studied in detail. The simulation results indicate that the powder temperature at the side of the cylinder wall is relatively high, and the powder temperature at the bottom blade of the agitator is relatively high relative to the upper part of the agitator. By comparing the simulation data with the experimental data, the simulated temperature plus powder particle damage energy agrees well with the experimental data. Moreover, the percentage of broken energy in the total energy of particles changes with time. The relationship between the proportion of broken energy and powder size is fitted, and it will become the basis of the powder broken simulation. The present results offer insights into the ball milling behaviors of the mixing procedure, which may also provide valuable information for material fabrication.