Effect of Guide Vane Openings and Different Flow Rates on Characteristics in Pump Mode of Pump-turbine with Splitter Blades

Abstract

With the development of smart power grid, pumped storage has been developing on a large scale, and the pump-turbine with splitter blades is widely used. A combination of experimental and CFX numerical simulation was carried out to investigate the influence of guide vane openings on the flow characteristics in pump-turbine with splitter blades at different flow rates. The results show that change in the guide vane openings and flow rates have significant impacts on the internal flow characteristics in pump mode. The findings also revealed a poor flow stability in the condition of a small opening at a high flow rate and the condition of large opening at a low flow rate. Under the influence of pressure fluctuation, there exists local high-speed flow at the outlet of the draft tube and mid-span between the runner and the guide vane.