Mechanism of runner high-pressure side on stall characteristics at typical unsteady operating points in both modes of a pump turbine

Stall phenomenon, a classical physical phenomenon which is located in the vaneless region of pump–turbine and accompanied by complex vortex evolution process, strongly related to formation hump unsteady at pump mode S turbine mode. In present paper, detached eddy simulation model employed numerically investigate impact runner high-pressure side (HPS) on stall characteristics typical operating points, namely, valley point runaway It found that both investigated points are obviously changed: For point, only three fixed cells exist original plan, while four additional rotating appear rotate speed 0.02nr (nr, rotation speed) optimized plan (OPT). The distinctive coexistence reported for first time attributed controlled HPS; intensity frequency characteristic slightly increased OPT. Moreover, HPS can effectively decrease backflow shroud, resulting significant relative rate within complete flow period, 17.3% 4.8% point. Finally, local hydraulic loss (LHLR) method adopted it high LHLR OPT more concentrated circumferential direction radial vanless points. Based with proposed many might be eliminated some extent.