Numerical study of similarity in prototype and model pumped turbines

27th IAHR Symposium on Hydraulic Machinery and Systems

Li, Z.J.^1 ; Wang, Z.W.^1 ; Bi, H.L.^1

Institute of Fluid Machinery and Fluid Engineering, Department of Thermal Engineering, Tsinghua University, Beijing

100084, China^1

关键词: Characteristic frequencies;    Draft tubes;    Pressure fluctuation;    Rotor-stator interactions;    Vortex formation;    Vortex rope;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/22/3/032049/pdf
DOI  :  10.1088/1755-1315/22/3/032049

来源: IOP

【 摘 要 】

Similarity study of prototype and model pumped turbines are performed by numerical simulation and the partial discharge case is analysed in detail. It is found out that in the RSI (rotor-stator interaction) region where the flow is convectively accelerated with minor flow separation, a high level of similarity in flow patterns and pressure fluctuation appear with relative pressure fluctuation amplitude of model turbine slightly higher than that of prototype turbine. As for the condition in the runner where the flow is convectively accelerated with severe separation, similarity fades substantially due to different topology of flow separation and vortex formation brought by distinctive Reynolds numbers of the two turbines. In the draft tube where the flow is diffusively decelerated, similarity becomes debilitated owing to different vortex rope formation impacted by Reynolds number. It is noted that the pressure fluctuation amplitude and characteristic frequency of model turbine are larger than those of prototype turbine. The differences in pressure fluctuation characteristics are discussed theoretically through dimensionless Navier-Stokes equation. The above conclusions are all made based on simulation without regard to the penstock response and resonance.