• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2016, Vol. 52 ›› Issue (24): 170-178.doi: 10.3901/JME.2016.24.170

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Study of Hump Instability Phenomena in Pump Turbine at Large Partial Flow Conditions on Pump Mode

YANG Jun1,2,3, YUAN Shouqi4, PAVESI Giorgio5, LI Chun1,2, YE Zhou1,2   

  1. 1. School of Energy and Power Engineering， University of Shanghai for Science and Technology， Shanghai 200093
    , 2. Key Laboratory of Flow Control and Simulation， University of Shanghai for Science and Technology， Shanghai 200093
    , 3. Key Laboratory of Fluid and Power Machinery of Ministry of Education， Xihua University， Chengdu 610039
    , 4. National Research Center of Pumps， Jiangsu University， Zhenjiang 212013
    , 5. Department of Industrial Engineering， University of Padua， Padua， 35131 Italy
  • Online:2016-12-15 Published:2016-12-15

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Abstract:

For middle- and high- specific speed pump turbines, the hump instability appearing at large partial flow conditions seriously restricts its stable operation range. These phenomena relate closely to the inner unsteady flow in pump turbine. We investigate the characterization of pressure fluctuation and the mechanism of unsteady flow by an experimental and numerical study of the unsteady flow occurring among the adjustable blades. For pump working at either full or part load conditions, two kinds of periodic pressure pulsations in the diffuser vane have been observed and analyzed. A hump instability appears only when the actual flow rate of head curve is 0.45-0.75 times of the designed value, and our frequency analysis further shows that its appearance is closely related to the two above pressure fluctuations.

Key words: hump instability, large partial flow conditions, pump mode, unsteady flow pattern, pump turbine

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