scholarly journals Research on Unsteady Characteristics of Pump Turbine in Pumping Mode

2021 ◽  
Vol 627 ◽  
pp. 012028
Author(s):  
Yong Liu ◽  
Hongjuan Ran ◽  
Dezhong Wang
Keyword(s):  
Pump Turbine ◽  
Pumping Mode ◽  
Unsteady Characteristics

scholarly journals Numerical Study of Pump-Turbine Instabilities Under Pumping Mode Off-Design Conditions

2015 ◽  
Author(s):  
Uroš Ješe ◽  
Regiane Fortes-Patella ◽  
Matevž Dular
Keyword(s):  
Power Plants ◽  
Numerical Study ◽  
Guide Vane ◽  
Characteristic Curve ◽  
Rotating Stall ◽  
Electrical Network ◽  
Pump Turbine ◽  
Wide Range ◽  
Pumping Mode ◽  
And Performance

Pumped storage power plants, using reversible pump-turbines, are a great solution to maintain the stability of an electrical network. The continuous operating area of reversible pump-turbines machines is usually delimited by cavitation or a hydraulic instability called hump phenomena at part load. If the machine operates under these off-design conditions, it might be exposed to vibrations and performance losses. The paper focuses on the numerical analysis of the pumping mode regime and pays special attention to the prediction of the hump shaped characteristic curve and associated rotating stall. The investigations were made on a high head pump-turbine design (nq=27) at model scale for four different guide vane opening angles and a wide range of flow rates. Numerical simulations were performed and analyzed in LEGI and were compared to the global experimental data, provided by Alstom Hydro.

Suppression of hump characteristic for a pump-turbine using leading-edge protuberance

2019 ◽  
Vol 234 (2) ◽  
pp. 187-194 ◽  
Author(s):  
Guo Zhiwei ◽  
Wang Chihang ◽  
Qian Zhongdong ◽  
Luo Xianwu ◽  
Xia Weipeng
Keyword(s):  
Experimental Data ◽  
Three Dimensional ◽  
Leading Edge ◽  
Wave Guide ◽  
Good Qualitative Agreement ◽  
Three Dimensional Flow ◽  
Pump Turbine ◽  
Guide Vanes ◽  
Pumping Mode ◽  
Dynamics Method

The application of wave guide vanes with bio-inspired leading-edge protuberances to the hump characteristic of a pump-turbine is examined in this study. Numerical simulation with a shear-stress transport turbulence model is used to calculate the three-dimensional flow in a pump-turbine in pumping mode. Three tubercle amplitudes of 0.02c, 0.04c, and 0.08c (c is chord length), and three spanwise wavenumbers (2/s, 4/s and 8/s, s is the length of span) for guide vanes are especially considered. The results obtained show that the simulated performances of original guide vanes are found to be in good qualitative agreement with experimental data, supporting the validation of the computational fluid dynamics method. For different wave guide vanes with leading-edge protuberances, it is shown that the hump characteristic of the pump-turbine in pumping mode is effectively improved. This is due to improved flow fields below the tongue in view of entropy production and vector field. The energy loss can be clearly compared through the entropy distribution for different locations of the guide vanes, and it is improved for the wave guide vanes with bio-inspired leading-edge protuberances. For current pump-turbine, the optimal amplitude and wavenumber are found to be around 0.04c and 4/s.

Large Eddy Simulation of the Rotating Stall in a Pump-Turbine Operated in Pumping Mode at a Part-Load Condition

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Olivier Pacot ◽  
Chisachi Kato ◽  
Yang Guo ◽  
Yoshinobu Yamade ◽  
François Avellan
Keyword(s):  
Reynolds Number ◽  
Large Eddy Simulation ◽  
Rotating Stall ◽  
Scale Model ◽  
Pump Turbine ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Pumping Mode ◽  
Stall Cells ◽  
Reduced Scale

The investigation of the rotating stall phenomenon appearing in the HYDRODYNA pump-turbine reduced scale model is carried out by performing a large-scale large eddy simulation (LES) computation using a mesh featuring approximately 85 × 106 elements. The internal flow is computed for the pump-turbine operated at 76% of the best efficiency point (BEP) in pumping mode, for which previous experimental research evidenced four rotating stall cells. To achieve an adequate resolution near the wall, the Reynolds number is decreased by a factor of 25 than that of the experiment, by assuming that the flow of our interest is not strongly affected by the Reynolds number. The computations are performed on the supercomputer PRIMEHPC FX10 of the University of Tokyo using the overset finite-element open source code FrontFlow/blue with the dynamic Smagorinsky turbulence model. It is shown that the rotating stall phenomenon is accurately simulated using the LES approach. The results show an excellent agreement with available experimental data from the reduced scale model tested at the EPFL Laboratory for hydraulic machines. The number of stall cells as well as the propagation speed agree well with the experiment. Detailed investigations on the computed flow fields have clarified the propagation mechanism of the stall cells.

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