Hydraulic loss analysis in a pump-turbine with special emphasis on local rigid vortex and shear

Since the pump as turbine is increasingly employed in energy storage, improving efficiency both and modes required for economic benefits. This study aims to analyze vortex flow characteristics control methods reduce hydraulic loss. In this paper, a delayed detached eddy simulation was applied low specific speed pump-turbine. Based on entropy production analysis vorticity binary decomposition local vortices, results show that shear leading cause of loss instead existence vortices. The average wake can be 1.6 times higher than jet regions mode, but there little difference distribution vortices mode. caused by rotor–stator interaction with tongue effect at blade passing frequency up threefold over without modes. Reducing ratio rigid via modification volute angle suppress an effective way decrease