Встановлення впливу швидкості обертання на енергетичну ефективність процесів подрібнення ударом, роздавлюванням та стиранням в барабанному млині

This study investigates a grinding process in a tumbling mill loaded by impact, crushing, and abrasion. The impact, compression, and shear interactions of particles are taken into account, the intensity of which is determined by the zones of flight, shear layer, and solid flow of the fill in the cross-section of the rotating drum chamber. The task addressed is to determine the influence of rotation speed on the energy intensity of the grinding process for individual loading mechanisms. An experimental method for numerical modeling of productivity analogs for grinding mechanisms by the energies of the corresponding interactions was applied. The energy intensity of the process was estimated by the ratios of productivity analogs and the relative power of rotation drive. Energy efficiency was determined taking into account experimental data on physical productivity and drive power of the mill model. The effect of rotation speed on grinding was experimentally estimated at a chamber filling degree of 0.45. The phenomenon of an intensive decrease in the energy intensity of the grinding process with a decrease in rotation speed was established. The results made it possible to identify energy-efficient values of the relative rotation speed for the grinding processes: coarse – by impact at ψω = 0.75–0.9, medium – by crushing at ψω = 0.55–0.65, and fine – by abrasion at ψω = 0.3–0.4. The established effect is explained by the revealed activation of interactions: impact – at high-speed, compressive – at medium-speed, and shear – at low-speed rotation. The established patterns enable prediction of rational technological parameters for energy-saving processes of multi-stage grinding in tumbling mills.