Pressure fluctuations in the vaneless space of High-head pump-turbines—A review

TLDR: In high-head pump-turbines, observations in the engineering field show that the most detrimental hydraulic instabilities are pressure fluctuations in the vaneless space, which can cause vibrations and fatigue failures in hydraulic components as mentioned in this paper.

Abstract: In high-head pump-turbines, observations in the engineering field show that the most detrimental hydraulic instabilities are pressure fluctuations in the vaneless space. For example, these pressure fluctuations can cause vibrations and fatigue failures in hydraulic components. It has been recognized that pressure fluctuations in vaneless space are induced primarily by the interactions between runner blades and guide vanes, i.e., rotor–stator interactions (RSI). The present paper presents and discusses studies in this field, which are carried out by various investigators. Studies include mechanism research on RSI, experimental and numerical investigations on RSI characteristics, discussions on the relationship between vibrations and pressure fluctuations, studies on the geometric and operating parameters of the unit that influence the pressure fluctuations in vaneless space, and precautions and countermeasures to reduce these pressure fluctuations.