Journal of Shanghai Jiaotong University ›› 2020, Vol. 54 ›› Issue (8): 805-812.doi: 10.16183/j.cnki.jsjtu.2019.081

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Influence of Parallel Impeller Inlet Trimming on Mixed Flow Pump as Turbine

YANG Sunsheng1,2(), SHAO Ke1, DAI Tao1   

  1. 1. National Research Center of Pump, Jiangsu University, Zhenjiang 212013, Jiangsu, China
    2. Zhenjiang Research Institute of Fluid Engineering Equipment Technology, Jiangsu University, Zhenjiang 212009, Jiangsu, China
  • Received:2019-03-26 Online:2020-08-28 Published:2020-08-18


To study the influence of impeller trimming on mixed flow pump as turbine, a turbine whose specific speed is 240 is designed. The impeller inlet has been trimmed in parallel for four times and its shroud and hub are retained. By using the method of CFD and test, the turbine performance is obtained and the internal flow of the mixed flow pump as turbine is analysed. The result shows that with the increase in the trimming ratio, the best efficiency point moves to the small flow region. In the small flow region, the shaft power rises and the head drops. In the large flow region, the shaft power drops and the head rises. The circulation flow between the impeller and the volute increases so that the highest efficiency of the turbine decreases. The theoretical formulas are used to predict the performance of the mixed flow pump as the best efficiency point of the turbine, and the efficiency and head are higher than those in the test results, with smaller errors. It can be found that the formulas of the impeller trimming of mixed flow pump are almost suitable for the impeller trimming of mixed flow pump as turbine.

Key words: impeller trimming, mixed flow pump as turbine, numerical simulation, theoretical formula

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