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Deyou L.,Harbin Institute of Technology | Hongjie W.,Harbin Institute of Technology | Gaoming X.,Harbin Institute of Technology | Ruzhi G.,Harbin Institute of Technology | And 3 more authors.
Renewable Energy | Year: 2015

Presently, hydropower is the world's largest source of renewable energy. Pump Storage Power Plant develops the rapidly because of its effective electricity storage and becomes the most part of hydropower. A pump turbine is the vital component of a Pump Storage Power Plant. To obtain efficient generation, safe and stable operation of a pump turbine is pretty important. However, the existence of the hump characteristics of a pump-turbine in pump mode usually leads to operating instability. Thus it is necessary to analyze regions of the hump characteristics. In this research experimental investigation and numerical simulation are employed in order to study the hump characteristics. Unsteady incompressible turbulent flow simulations for the full pump turbine model water domain are performed using the SST k-ω turbulence model. A refinement grid is generated, which allows the corresponding y-plus values of the runner blades, stay vanes and guide vanes less than 2 in average. Calculation results of torque in different discharges as well as head and efficiency in the small discharge regions are in solid agreement with the experimental data. The results show that there are three vortex groups which distribute in the tandem cascade passages when entering the hump region. They are equally located in the circumferential direction in the tandem cascade, and one vortex group is located in two passages of the special stay vane. The strength and range of the vortex group change with different discharges. It also shows certain instability during one runner revolution. This work can provide a basic understanding for the improvement of the stable operation of a pump turbine. © 2014 Elsevier Ltd.

Ji X.-Y.,Wuhan University | Ji X.-Y.,Harbin Institute of Large Electrical Machinery | Lai X.,Wuhan University
Shuidonglixue Yanjiu yu Jinzhan/Chinese Journal of Hydrodynamics Ser. A | Year: 2011

The question of startup is more and more in turbine mode of the pump-turbine at present. It is key technology to the pumped storage power station. The flow regimes of the pump-turbine were calculated by SST k-ω turbulence model to study the hydraulic behaviors on the 'S' area in turbine mode at various guild van openings and mass flows. Comparing the results of the calculation and the test, it is shown that the reasonable method is applied. The across flow is a great factor to the startup in turbine mode of the pump-turbine.

Liang Y.-P.,Harbin University of Science and Technology | Sun Y.,Harbin University of Science and Technology | Sun Y.-T.,Harbin Institute of Large Electrical Machinery
Dianji yu Kongzhi Xuebao/Electric Machines and Control | Year: 2011

The transposition technique of stator bar is one of the key techniques in 1000 MW hydro-generator design, and the suitable transposition method can reduce the circulating current losses of stator winding better, and improve the efficiency. Four common transposition methods for hydro-generator were analyzed in this paper, including 360° bar transposition, 0°/360°/0°bar transposition with void, deficient 360° void bar transposition and 0°/360°/0° extended bar transposition. The circulating current losses of stator bar for 1000 MW hydro-generator with four transposition methods were calculated and analyzed using leakage susceptible potential method. The calculation results indicate that the transposition methods have great influence on distribution of circulating current losses, and the losses are the smallest when using 0°/360°/0° prolonged transposition method for hydro-generator, accounting for 15.3% of 360° bar transposition circulating current losses, followed by deficient 360° void bar transposition, occupying 25.9% of 360° bar transposition circulating current losses.

Wang L.,Zhejiang University | Yin J.,Zhejiang University | Jiao L.,Zhejiang University | Wu D.,Zhejiang University | Qin D.,Harbin Institute of Large Electrical Machinery
Science China Technological Sciences | Year: 2011

The performance of a reversible pump turbine with S-shaped characteristics is of great importance to the transition processes such as start-up and load rejection. In order to predict the S-shaped curve accurately and develop a reliable tool for design improvement, a shear stress transport model (SST) with various numerical schemes for pressure term in the governing equation was investigated in a whole pump turbine including spiral casing, stay vanes, guide vanes, runner and draft tube. Through the computation, it was shown that different zones in the curve should employ different schemes to get the solution converged. Comparison of discharge-speed performance showed that good correspondence is got between experimental data and CFD results. Based on this, internal flow analysis was carried out at three typical operating points representing turbine mode, shut-off mode and reversible pump mode, respectively. According to the flow field concerned, the mechanism for the speed-no-load instability was explained, which provides good guidelines to take countermeasures in future design. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg.

Wang L.-Q.,Zhejiang University | Liu J.-T.,Zhejiang University | Zhang L.-F.,Harbin Institute of Large Electrical Machinery | Qin D.-Q.,Harbin Institute of Large Electrical Machinery | Jiao L.,Zhejiang University
Zhejiang Daxue Xuebao (Gongxue Ban)/Journal of Zhejiang University (Engineering Science) | Year: 2011

One power plant's pump-turbine was modeled in order to analyze the field characteristic with low flow conditions in pump mode of pump-turbine. The flow characteristic in pump mode was simulated by SIMPLEC algorithm and shear stress transmission (SST) k-ω mode. The flow of runner and vanes was analyzed when pump mode was at the condition of that guide vanes were in designed opening and low flow. The performance of pump-turbine was analyzed combined with experimental results. Results show that the head line is in the small amplitude fluctuations when the flow is 15%~53% of designed flow and vanes are in designed opening. The phenomenon like a jet between vanes is more obvious when lower flow. The number of vortex is gradually increasing with lower flow, and its scale becomes larger so that the field between stay vanes and guide vanes are filled with vortex. It is the vanes that make the head of pump-turbine fluctuate in small amplitude when the flow is low. Those results can be used to guide the pump-turbine's optimal design.

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