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Zhu B.,Tsinghua University | Wang X.,Tsinghua University | Tan L.,Tsinghua University | Zhou D.,State Grid Corporation of China | And 2 more authors.
Renewable Energy | Year: 2015

Frequent changes between pump and turbine operations pose significant challenges in the design of pump-turbine runners with high efficiency and stability. In this study, a multiobjective optimization design system, including a 3D inverse design, computational fluid dynamics, design of experiment, response surface methodology, and multiobjective genetic algorithm, is introduced and applied to the design of a middle-high-head pump-turbine runner. The key parameters in the design, including the blade loading, the blade lean at the high-pressure side of the runner, and the meridional channel shape, were selected as the optimized parameters. Two runners, one with a large positive blade lean and another with a large negative blade lean, were selected for further numerical investigations and measurements. Model tests show that both runners have good power performances. The runner with a negative blade lean has better stability than the runner with a positive blade lean. © 2015 Elsevier Ltd.

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.

Zhou Y.,Harbin Institute of Technology | Chen S.,Harbin Institute of Technology | Li C.,Harbin Institute of Large Electrical Machinery
Advanced Materials Research | Year: 2012

Synergistic inhibition effect of sodium oleate and sodium vanadate on the corrosion of pure aluminum in NaCl solution has been investigated by open circuit potential, potentiodynamic polarization curve, and electrochemical impedance spectroscopy(EIS). Experiment results show that the pure aluminum has the lowest corrosion current density under the optimum technological conditions at room temperature, which can be expressed as follows: the 3.5wt.% NaCl solution contains two inhibitors of sodium oleate and sodium vanadium, and their mole concentration ratio is 1:2, solution pH value is 8.0∼8.5. In addition, these two inhibitors have played the major role of corrosion inhibition at different stage respectively, which can be attributed to the formation of continuous phase on the surface of pure aluminum. © (2012) Trans Tech Publications, Switzerland.

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.

Ge B.,Harbin University of Science and Technology | Li M.,Harbin University of Science and Technology | Sun Y.,Harbin Institute of Large Electrical Machinery | Li J.,Harbin Institute of Large Electrical Machinery | Hu L.,Harbin Institute of Large Electrical Machinery
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2013

Nowadays hydro-generators are usually equipped with the damper winding. The accuracy of the calculated the damper windings currents will affect the generator's performance directly. Especially when generator operates in asymmetric conditions, the currents induced by the negative magnetic field will influent the generator's performance greatly. Therefore, to calculate the currents of the damper windings accurately gets really necessary while studying the asymmetric performance of the generator. The field-circuit coupled method is applied in the paper to calculate the damper winding currents as the generator operates in asymmetric conditions. By building the mathematical model of the damper winding' send, the effect from the nonlinear magnetic field at the end of the rotor is considered in the paper. Meantime the damper winding currents are also calculated through the conventional process which deal the magnetic field at the end of the damper winding with analytical method. And then, the calculated results from the both methods mentioned above are compared with the results acquired from the test, in which the instantaneous value of the damper bars currents can be measured directly. The comparison shows that the method applied in the paper is more accurate when calculating the damper winding currents when the magnetic field at the end of the rotor saturates extremely. © 2013 Chinese Society for Electrical Engineering.

Sun Y.,Harbin Institute of Large Electrical Machinery | Luan Q.,Harbin Institute of Large Electrical Machinery
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2014

Working group subjects and academic papers for study committee of rotating electric machines of CIGRE'2014 are introduced. The scope involves technology progress of turbogenerators, hydrogenerators, wind-driven generators and large motors in the areas of CIGRE Study Committee Al: rotating electric machines (CIGRE SC A1). © 2014 State Grid Electric Power Research Institute Press.

Zhang G.,Harbin Institute of Large Electrical Machinery | Wei X.,Harbin Institute of Large Electrical Machinery
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2014

Sediment erosion of hydraulic turbine is the complicated engineering problem related to such factors as operating conditions of hydraulic turbine, solid-liquid two-phase flow characteristics and sediment properties. In this paper, the three dimensional full channel geometric model of prototype turbine is established to understand change in internal pressure of runner and sediment distribution in runner channel under different sediment flow conditions. The hydraulic turbine mainly consists of spiral case, vane, runner and draft tube. Every part generates its corresponding independent meshes, and then is connected with each other by internal interfaces. The total number of grid cell is 7 888 784 in computational domain. Considering solid-liquid interactions fully, based on Eulerian-Eulerian multiphase flow model, Reynolds-averaged Navier-Stokes and RNG k-ε turbulence equations are numerically solved to study internal flows of hydraulic turbine runner under different sediment flow conditions. Research results show that pressure distributions on runner blade surfaces are similar under clear and sandy water flow conditions, i. e., from blade inlet to outlet edges, pressure gradually decreases, and there is a uniform transition without obvious local distortion in pressure field, but the surface pressure is slightly higher in the case of sediment flow. It is further found that surface pressure increases linearly with sediment concentration, and first increases and then decreases with the increase of sediment particle size. Sediment concentration is low on the pressure surface of blade near inlet edge, gradually increases towards the edge and attains its maximum value on the edge. Solid-liquid two-phase flow speed is high and blade thickness is small near outlet edge, so erosion destruction is easy to occur there. Under the conditions of the same sediment particle size, change in sediment concentration has little effect on sediment distribution on blade surface. Also, under the conditions of the same sediment concentration, small sediment particles evenly distribute on runner surface with low concentration, and large ones are clustered in the regions of blade leading and outlet edges to cause local serious erosion of runner blades. Finally, velocity difference between solid and liquid phases is discussed to analyze reasons for change in sediment distribution on blade surface in this paper. The results show that as far as this study is concerned, with the increase in sediment concentration, velocity difference changes a little under the conditions of the same sediment particle size. In this case, the solid-liquid two-phase flow structure is maintained, and pressure distribution is basically the same on blade surface. On the other hand, with the increase of sediment particle size, velocity difference gradually increases under the conditions of the same sediment concentration. The ability of sediment particle to follow water movement becomes bad, which makes sediment particle easily deviate from water streamline under the conditions of large-size sediment flow. Flow separation occurs in the flow direction and the regions where flow velocity changes significantly, and sediment particles hit blade surface to cause serious erosion of blade surface material. This study can provide technical references for the sediment control design of turbine runner operating in sediment-laden rivers. ©, 2014, Chinese Society of Agricultural Engineering. All right reserved.

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.

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 | Liu Y.,Zhejiang University | Liu W.,Harbin Institute of Large Electrical Machinery | Qin D.,Harbin Institute of Large Electrical Machinery | Jiao L.,Zhejiang University
Paiguan Jixie Gongcheng Xuebao/Journal of Drainage and Irrigation Machinery Engineering | Year: 2013

To study the hydraulic instability of a pump-turbine at the pump mode under different working conditions, the three-dimensional, unsteady flow in the whole passage of the pump-turbine was conducted by using computational fluid dynamics software-Fluent under the optimal, low and high flow rate conditions. The pressure fluctuations were monitored respectively at the inlet of spiral casing, in the interface of runner and guide vanes, and in the space between head cover and runner, as well as in draft tube. The results show that a larger pressure fluctuation can be found in the interface of runner and guide vanes and in the space between the runner and head cover, while the pressure fluctuation is lower at the inlet of the spiral casing and in the draft tube. The pressure fluctuation is the smallest under the optimal condition; the larger the working condition deviates from the optimal one, the more considerable the fluctuation is. The dominant frequency of pressure fluctuation depends on the locations monitored. The dominant frequencies are integer multiples of the blade passing frequency and the runner rotational frequency in the interface of runner and guide vanes and in the space between runner and head cover, respectively. However, the dominant frequencies of the pressure fluctuation at the inlet of the spiral casing and in the draft tube are mainly related to low-frequency components.

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