Influence of clearance leakage flow on cavitation and pressure pulsation characteristics in a high-speed centrifugal pump

Cavitation is a critical factor affecting the operation stability of high-speed centrifugal pumps, which should be concentrated on during the pump design and operation. This study employs the numerical method to investigate the influence of different wear-ring structures on the flow field and cavitation-induced pressure pulsation characteristics of a high-speed centrifugal pump, and unsteady simulations were conducted for single and three rings under non-cavitation, critical cavitation, and 10% head-drop conditions. Results show that the three-ring configuration exhibits a larger cavitation zone within the impeller and more significant flow separation. In contrast, the single ring generates more uniform flow through the impeller passages. Regarding cavitation excitation characteristics, the three-ring structure induces higher amplitude at the blade-passing frequency 1.0fBPF for the pump under non-cavitating conditions. Under the critical cavitation and 10% head-drop conditions, the amplitudes at 0.5fBPF, 1.0fBPF, and their harmonic frequencies are significantly greater at the three-ring configuration compared to the single ring. It is concluded that increasing the number of wear rings enhances leakage control capability, and it aggravates the extent of cavitation within the impeller and intensifies cavitation-induced pressure pulsations. This study provides theoretical support for the optimal design of high-speed centrifugal pumps.