Open Access

ARTICLE

Numerical Investigation of Cavitation-Induced Flow Dynamics and Pressure Fluctuations in a Pump-Turbine

Chao Liu¹, Jianwu He^2,*

1 School of Intelligent Manufacturing and Vehicle Engineering, Guang’an Vocational & Technical College, Guang’an, China
2 School of Civil and Architectural Engineering, Guizhou University of Engineering Science, Bijie, China

* Corresponding Author: Jianwu He. Email:

Fluid Dynamics & Materials Processing 2026, 22(9), 9 https://doi.org/10.32604/fdmp.2026.086616

Received 07 June 2026; Accepted 04 September 2026; Issue published 28 September 2026

Abstract

This study investigates the influence of the cavitation coefficient on the internal flow field and pressure fluctuation characteristics of a pump-turbine using numerical simulations validated against experimental measurements. The validated model is then used to analyze hydraulic performance and cavitation-induced flow behavior over a range of cavitation conditions. The results show that cavitation first develops on the suction side of the runner blades near the outlet and progressively reduces hydraulic efficiency as it intensifies. The flow field within the runner is primarily governed by rotor-stator interactions between the runner and guide vanes, resulting in pronounced fluctuations of the flow variables. As the cavitation coefficient decreases, the vapor volume fraction increases, the flow becomes increasingly unstable, and pressure fluctuations at the blade-passing frequency (BPF) in the vaneless region become more pronounced. Under severe cavitation conditions, secondary backflow develops along the outer side of the elbow, while the amplitude of low-frequency pressure fluctuations associated with vortical structures in the draft tube increases significantly, compromising the operational stability of the unit.

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Keywords

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