DEM simulation of energy transitions in a hammer mill: Effect of impeller configurations, agitation speed, and fill level

Abstract In this study, a numerical approach is employed to investigate the flow and energy transitions characteristics of particles in a horizontal drum equipped with rotational flat blade. The results indicated that the dominant energy dissipation mechanisms were the internal friction between particles, the friction between particles and wall, and the damping loss of collision between particles. The mean tangential velocity and blade torque increased monotonously with the increase of fill level and blade speed. The dimensionless mean velocity in the tangential direction was dependent on the fill level and mill geometry instead of impeller agitation rate. In sequence, the characteristic parameters related to the geometric features and operational conditions were established to characterize the energy input in the agitator. The blade torque was characterized as a linear function of the characteristic parameter TS, which is determined by mill geometry and operational conditions.