Suppression effect of bionic guide vanes with different parameters on the hump characteristics of pump-turbines based on entropy production theory

Based on the principles of bionics, this study drew on the protuberances of the leading edge of a humped whale flipper, designed different bionic protuberances applied to stay-guide vanes, and conducted three-dimensional numerical simulation research on the pump-turbine pump mode with an opening of 28.5 mm. The Euler theory and hydraulic loss entropy production analysis method was used to compare and analyze the pump characteristics of different schemes. The results showed that the bionic protuberances could effectively destroy the coherent structure of turbulence in the flow field, thereby improving the internal flow regime of the runner channel and significantly reducing flow separation. The protuberances can reduce the flow angle of the runner outlet by 5%–10%, resulting in an increase in the Euler head by 3%, which significantly increases the hump margin. In addition, bionic protuberances can effectively improve the flow regime in the stay-guide vanes and runner and weaken the flow separation, thereby avoiding the generation of a high local entropy production region and reducing the hydraulic loss by 4%. Therefore, protuberances can effectively improve the hump characteristics.