Investigation on the influence of jetting equipment on the characteristics of centrifugal pump

Abstract

To reduce radial noises from the motor of centrifugal pumps, this study designed a water cooling system called jettingequipment to replace traditional fan cooling systems in pump motors. By measuring radiated noises, head, efficiency, andcavitation performance, the research compared the differences among experimental results of the original pump unit,the one with a normal design jetting pipe and another one with a larger jetting pipe. Results show that the radiatedsound pressure level of the model pump was significantly reduced by 8.3 dB after integrating the jetting pipe. With a nor-mal jetting pipe, no significant changes were observed in the head, efficiency, and shaft power curves, and cavitation per-formance improved under small flow rate. However, the performance with the larger jetting pipe worsened, except thehump phenomenon of the model pump under a small flow rate was enhanced. Computational fluid dynamics methodwas used to calculate the internal flow of three model pumps in order to investigate the jetting flow effect. A compari-son among the flow fields at the inlet of the three types of pumps indicated that high-pressure water injection can effec-tively control inlet recirculation and improve velocity distribution in the inlet flow field with decreased recirculationvortex strength and recirculation onset critical flow rate.