Investigation on pressure fluctuation in a Francis turbine with improvement measures

27th IAHR Symposium on Hydraulic Machinery and Systems

Feng, J.J.^1 ; Li, W.F.^1 ; Wu, H.^1 ; Lu, J.L.^1 ; Liao, W.L.^1 ; Luo, X.Q.^1

Institute of Water Resources and Hydro-Electric Engineering, Xi'An University of Technology, Xi'an

710048, China^1

关键词: Flow deflector;    Improvement measure;    Output power;    Part load conditions;    Power out put;    Pressure fluctuation;    Runner cones;    Vortex rope;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/22/3/032006/pdf
DOI  :  10.1088/1755-1315/22/3/032006

来源: IOP

【 摘 要 】

For a prototype turbine operating under part load conditions, the turbine output power is fluctuating strongly. The test for the prototype turbine at site shows that the main reason is the resonance between the draft tube vortex frequency and the generator natural frequency. In order to reduce the fluctuation of power output, different measures are investigated with using CFD methods. To keep the turbine unchanged, four kinds of draft tubes are examined, including the original draft, the draft tube with extending runner cone, the draft tube with damping gates and the draft tube with flow deflectors. The results are analyzed and compared in order to examine the effects on pressure fluctuation and formation of vortex rope of draft tube. It is found that adding flow deflector is the most effective to change the frequency of the draft tube vortex rope and reduce the amplitude of pressure fluctuation.