Thermal optimization and experimental research of high-speed universal pulverizer

Abstract

Because of high efficiency, energy conservation, simple operation, wide application range, and small size, the high-speed universal pulverizer has been well received by customers. However, its electrical motor can overheat when working, which hinders continuous operation of the pulverizer. In this study, a series of efforts were made to address this problem. Firstly, a detailed analysis of the working principle of the pulverizer was conducted and an optimization plan was proposed, consisting in punching ventilation holes on the surface of the original pulverizer. Simulations of the pulverizer flow field before and after optimization were performed. The hydrodynamic simulation results were used to conduct a steady state thermal analysis of the pulverizer, investigating the influence of the flow field on heat transfer. Additionally, experimental investigations were conducted on the pulverizer before and after optimization in order to measure and compare the parameters (motor working temperature, wind speed and temperature of the motor cooling system, vibration, noise, and pulverizing degree of the material) influencing the performance of the pulverizer. The numerical simulation results showed an increment in heat transfer caused by increment in air flow volume and velocity when air was injected into the pulverizer through bottom and side holes. Experimental results showed that the pulverizer with air injection through holes had the best performance when temperature, vibration, and refinement effect were considered as performance indicators.