Study on the internal flow and pressure pulsation of high specific speed centrifugal pump under different degrees of cavitation

With the development of hydraulic machinery toward high-speed operation, high-specific-speed centrifugal pumps are widely employed across various sectors. Cavitation can reduce the performance of pumps, disrupt internal flow regimes, and increase flow losses. Therefore, analyzing the interaction between cavitation and flow rate on pressure pulsation, as well as exploring the change characteristics and mechanisms of internal flow dynamics, is critical for developing low-vibration hydraulic model design methods for high-specific-speed centrifugal pumps. Under both rated and non-rated flow conditions at three cavitation residual points (initial cavitation, critical cavitation, and deep cavitation), the cavitation characteristics of a high-speed centrifugal pump were studied using experimental and numerical simulation methods. An experimental platform for centrifugal pump cavitation was built to verify the feasibility and accuracy of the computational approach. The pressure and velocity distribution characteristics, along with the mapping relationship between vorticity and cavitation bubbles in the flow field, were investigated through numerical calculations. Relationships and distribution laws between cavitation and the flow field were established. Additionally, the vibration characteristics of pressure pulsations at the pump inlet, blade surfaces, and volute walls were analyzed. The variations in pressure pulsation characteristics were examined, and the primary flow-induced excitation characteristics in the model pump were summarized. From 0.8Q0 to 1.2Q0, average pressure increases gradually. The primary frequency corresponding to the blade frequency.