Bionic Control of the S-shaped Instability Region of a Pump-turbine

doi:10.3901/JME.2025.12.336

Abstract

Abstract: As a critical equipment of pumped storage power station, pump-turbine’s stable operation is of great importance. However, pump-turbine has an S-shaped instability region in its characteristic curve. For the pump-turbine’s start-up, shutdown and condition transformation, it usually passes through the S-shape instability region. Bionic guide vanes inspired by the humpback whale flipper are designed to improve the pump-turbine’s stability in S-shape region. The control mechanism of bionic guide vanes on internal flow and pressure pulsation are analyzed. The analysis results show that when the pump-turbine operates in the S-shaped region, vortices appear near the suction side of guide vanes by shearing action between upstream flow and high-speed water ring in the vaneless region. There exists a special low-speed zone inside the water ring, which reduces the pump-turbine’s stability. By using the bionic guide vanes, the vortices are reduced and significantly weakened, the low-speed zone is reduced, so the S-shaped instability region in the pump-turbine’s characteristic curve is narrowed down and low-frequency pressure pulsation is decreased by 31.2%. The leading edge protuberances change flow pattern inside the boundary layer of guide vane, which reduce the amplitudes of low-frequency pressure pulsation by 51.2% and the risk of sympathetic vibration in the pump-turbine’s S-shape region.

Key words: pump turbine, S-shaped characteristics, bionic guide vane, pressure pulsation

CLC Number:

TV734

LU Jie, SHI Junde, ZHOU Daqing, QIAN Zhongdong. Bionic Control of the S-shaped Instability Region of a Pump-turbine[J]. Journal of Mechanical Engineering, 2025, 61(12): 336-343.

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