Influence of guide vane profile on the flow energy dissipation in a reversible pump-turbine at pump mode

Abstract

Pumped storage hydro (PSH) is a mature and widely used energy storage technique. The hydraulic dissipation of PSH will lead to the decline of power station efficiency. Therefore, it is important to find the reasons flow energy dissipation (FED). The adjustment of the flow channel will cause the change of flow energy dissipation. Guide vane is an important component of pump turbine, which has an influence on the problems of FED. In this paper, the FED in pump turbine with two guide vane profiles are analyzed. The combination of experimental method and numerical simulation method is adopted. Through experiments, the influence of two guide vane profiles on performance is clarified, and the method to judge the severity of Q-H instability is proposed. The FED under different working conditions were analyzed by entropy production. When the flow rate is at design point, the wake and local small flow separation causes FED. When the flow rate is large, FED is caused by the strong wake and flow separation in the runner. When the flow is small, the complex flow pattern in guide vane and back-flow cause high FED. The guide vane profiles have a great influence on FED. The match of blade leading edge and flow direction and flow control ability of guide vane affect the flow state caused the variation of FED.