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：10.1088/1755-1315/240/7/072035
出版社：IOP Publishing
摘要：Cavitation in water turbine can induce blade erosion, efficiency decrease and unit vibration, and in some extreme conditions the reverse water hammer caused by draft-tube cavity collapse may lead to the unit-lifting accident. The purpose of this work was to analyse the influences of cavitation on pressure pulsation characteristics of a prototype pump-turbine. We conducted 3D CFD simulations by giving different cavitation coefficients that induce different cavity volumes at the draft-tube inlet. In one of severe cavitation conditions, the propagation characteristics of cavitation pressures across the whole flow channel was studied, which was considered as the leading pulsating source. The correlation between pressure impulse and vapour fraction is successfully confirmed by observing the formation, development and collapse of the cavity in flow fields. The results indicate that the cavity, originating from the runner cone, evolves with various shapes, varying volumes and random periods, causing the wide spectrum band of frequencies of pressure pulsations. These results may lay the foundation for further studying extreme transient processes with cavity collapse.
