Dynamic characteristics of a pump-turbine during hydraulic transients of a model pumped-storage system: 3D CFD simulation

27th IAHR Symposium on Hydraulic Machinery and Systems

Zhang, X.X.^1 ; Cheng, Y.G.^1 ; Xia, L.S.^1 ; Yang, J.D.^1

State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan

430072, China^1

关键词: 3-D (three-dimensional);    CFD (computational fluid dynamics);    Dynamic characteristics;    Dynamic performance;    Dynamic trajectories;    Hydraulic transients;    Method of characteristics;    Pressure dependent;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/22/3/032030/pdf
DOI  :  10.1088/1755-1315/22/3/032030

来源: IOP

【 摘 要 】

The runaway process in a model pumped-storage system was simulated for analyzing the dynamic characteristics of a pump-turbine. The simulation was adopted by coupling 1D (One Dimensional) pipeline MOC (Method of Characteristics) equations with a 3D (Three Dimensional) pump-turbine CFD (Computational Fluid Dynamics) model, in which the water hammer wave in the 3D zone was defined by giving a pressure dependent density. We found from the results that the dynamic performances of the pump-turbine do not coincide with the static operating points, especially in the S-shaped characteristics region, where the dynamic trajectories follow ring-shaped curves. Specifically, the transient operating points with the same Q11and M11in different moving directions of the dynamic trajectories give different n11. The main reason of this phenomenon is that the transient flow patterns inside the pump-turbine are influenced by the ones in the previous time step, which leads to different flow patterns between the points with the same Q11and M11in different moving directions of the dynamic trajectories.