期刊名称：IOP Conference Series: Earth and Environmental Science
印刷版ISSN：1755-1307
电子版ISSN：1755-1315
出版年度：2019
卷号：240
期号：7
页码：1-11
DOI：10.1088/1755-1315/240/7/072031
出版社：IOP Publishing
摘要：The hump characteristic in pump mode is one of unique instabilities in pump-turbines. Recently, it is found that the cavitation has a large influence on hump characteristic. Hence, in this paper, a specific speed (nq=36.1) pump-turbine model was investigated experimentally in pump mode under different guide vane openings to verify the influence of cavitation on hump characteristic. Firstly, performance characteristic experiments were carried out to obtain the hump characteristics under three cavitation coefficients. The influence of cavitation on hump characteristics was analysed. Then, observation of cavitation at the runner inlet was conducted using the high speed camera. The cavitation at the runner inlet was presented. Finally, pressure fluctuation experiments were performed to analyse the characteristic frequencies and their variation with the cavitation coefficient. Through the analysis of pressure fluctuations, the hump characteristic is related to the low frequency pressure fluctuations, Analysis reveals that the strength of cavitation at the runner inlet has an obvious influence on low frequency pressure fluctuations, which leads to the change of the hump characteristic.
