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：2
页码：1-8
DOI：10.1088/1755-1315/240/2/022066
出版社：IOP Publishing
摘要：Hydro turbines are often used at off-design point to adjust the power output. At off-design condition, a swirl flow occurs downstream of the turbine runner and a cavitation occurs at the vortex core due to the decrease of the pressure. The cavitation in the draft tube can cause a flow instability called draft tube surge. Because the draft tube surge causes the flow rate fluctuation, unsteady fluid forces occurs on the runner, and consequently, the revolution speed of the runner is affected. In the present study, an experimental investigation was carried out. Characteristics of the dynamic fluid forces due to the draft tube surge are examined at first. In addition, the influence of the fluctuation of the revolution speed of the runner on the cavitation surge were examined. The results showed that the cavitation surge caused the hydraulic torque fluctuation on the runner but the fluctuation of the cavity volume were affected by the runner revolution speed.
