State Key Laboratory of Hydropower Equipment

Harbin, China

State Key Laboratory of Hydropower Equipment

Harbin, China
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Jia Y.,Harbin Institute of Technology | Jia Y.,Harbin Electrical Power Equipment Co. | Wei X.,State Key Laboratory of Hydropower Equipment
Paiguan Jixie Gongcheng Xuebao/Journal of Drainage and Irrigation Machinery Engineering | Year: 2015

In order to design and validate the auxiliary impeller required by the cycle power of the oil-lubricated external circulation cooling system on the reactor coolant pump's bi-directional thrust bea-ring, the CFD method is applied to present a numerical analysis for the pressure feature and flow rate within the oil impeller. The objective is to demonstrate the vector distribution of the relative velocity on the center surface of the flow path, and to verify the possibility of creating any flush angle from the inlet flow of the vane, the pros and cons of the vane shape design and how well it functionally matches the vane. The numerical analysis intuitively reflects the flow parameters and patterns generated by the designed shape of the vane, indicates the fact that the velocity at the vane's inlet mainly affects the tangent angle; thus, effectively lowers the damaging impact on any system devices located adjacent to the rear outlet of the vane. Through simulation of the oil-lubricating circulation, numerical analysis are comparatively analyzed with the testing results, for all 5 complete working processes, deviations are uniformly less than 5% and precisely satisfied lubricating oil's flow, head, zero-impact on flows and other operating requirements. This paper concludes the practical application of a simplified numerical analysis and reasoning could replace the repetitive testing employed in the traditional design process for axial auxiliary impellers. It has been successfully applied in the design of reactor coolant pump. ©, 2015, Editorial Department of Journal of Drainage and Irrigation Machinery Engineering. All right reserved.

Yin J.-L.,Shanghai JiaoTong University | Wang D.-Z.,Shanghai JiaoTong University | Wei X.-Z.,State Key Laboratory of Hydropower Equipment | Wang L.-Q.,Zhejiang University
Journal of Fluids Engineering, Transactions of the ASME | Year: 2013

For pump turbines, an S-shaped curve can lead to failures in synchronization. To improve the hydraulic design, the component that is responsible for the formation of the S-shaped curve was identified by a hydraulic loss analysis using previous computational fluid dynamics (CFD) results, which indicates that the formation of the S-shaped curve can be ascribed to the runner. To improve the hydraulic design of the runner, a simple numerical approach for direct problem analysis was proposed, based on the bladeloading distributions of runners with and without an S-shaped curve, and directly analyzed. It was implied from the differences in the blade-loading distributions that, when the meridional passage was broadened, the formation of the S-shaped curve was suppressed. To validate this, two runners with different meridional sections were designed by means of the inverse design method. Through model tests, it was verified that the S-shaped curve was eliminated completely and the performance curve of the modified hydraulic model satisfied the requirements for safe operation in a pumped storage plant. Copyright © 2013 by ASME.

Yin J.,Shanghai JiaoTong University | Wang D.,Shanghai JiaoTong University | Walters D.K.,Mississippi State University | Wei X.,State Key Laboratory of Hydropower Equipment
Science China: Physics, Mechanics and Astronomy | Year: 2014

Instability of pump turbine with S-shaped curve is characterized by large fluctuations of rotational speed during the transient processes. For investigating this phenomenon, a numerical model based on the dynamic sliding mesh method (DSSM) is presented and used to numerically solve the 3D transient flow which is characterized by the variable rotation speed of runner. The method is validated by comparison with measured data for a load rejection process in a prototype pump turbine. The results show that the calculated rotation speed agrees well with the experimental data. Based on the validated model, simulations were performed for the runaway process using an artificially assumed operating condition under which the unstable rotation speed is expected to appear. The results confirm that the instability of runner rotational speed can be effectively captured with the proposed method. Presented results include the time history profiles of unit flow rate and unit rotating speed. The internal flow characteristics in a typical unstable period are discussed in detail and the mechanism of the unstable hydraulic phenomenon is explained. Overall, the results suggest that the method presented here can be a viable alternative to predict the dynamic characteristics of pump turbines during transient processes. © 2014 Science China Press and Springer-Verlag Berlin Heidelberg.

Pang L.-J.,State Key Laboratory of Hydropower Equipment | Zhong S.,State Key Laboratory of Hydropower Equipment | Bu L.-F.,Harbin Electrical Machinery Company Ltd | Hu J.-W.,Harbin Electrical Machinery Company Ltd
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2012

The vibration source of abnormal noise produced when water turbine unit 1# is running was investigated through vibration and noise tests of two Francis turbines in a certain hydraulic power station. The natural frequency of the penstock was tested at the butterfly valve floor by hammering method. It is found that when the load reaches above approximately 92 percent, certain hydraulic exciting frequency will couple with the natural frequency of the penstock and cause resonance phenomenon, which is the main cause of abnormal noise. Furthermore, the scheme of modifying the outlet edge of butterfly valve and adding guide plate to the man door of the spiral case was proposed. By improving the through-flow environment, the hydraulic exciting frequency was increased greatly and the energy of vortex was reduced. The method has very good effect on mitigating vibration. The research indicates that the expedite through-flow environment is of significance on avoiding resonance of structure caused by hydraulic excitation or vortex vibration.

Wu B.,Jilin University | Sun W.,Jilin University | Li Z.,Jilin University | Li Z.,State Key Laboratory of Hydropower Equipment
Journal of Sound and Vibration | Year: 2011

This rapid communication is concerned with the circular whirling and stability of a model rotor in a synchronous generator under no load, subjected to unbalanced magnetic pull and mass eccentric force. The analysis is focused on the synchronous whirling of the rotor. Based on the existing analytical expression for unbalanced magnetic pull with any pole-pair number, the nonautonomous system of differential equations of motion with parametrically exciting force is transformed to an autonomous one by introducing a rotating coordinate frame. The circular whirlings of the model rotor are thus converted into equilibrium solutions to the autonomous system, which can be obtained by solving a system of polynomial equations with two unknowns only. Furthermore, stability of these equilibrium solutions is determined by applying the linearized stability criterion. An example is used to illustrate the proposed analytical method. © 2011 Elsevier Ltd. All rights reserved.

Yin J.-L.,Zhejiang University | Liu J.-T.,Zhejiang University | Wang L.-Q.,Zhejiang University | Wei X.-Z.,State Key Laboratory of Hydropower Equipment
Kung Cheng Je Wu Li Hsueh Pao/Journal of Engineering Thermophysics | Year: 2011

In order to investigate the pressure fluctuation characteristics in the guide vanes and stay vanes of pump turbine under off-design conditions, unsteady renolds averaged Navier-Stokes simulation(URANS) detached eddy simulation(DES) were carried out. The results showed that the DES method can be used to capture the pressure fluctuation characteristics. And then, the pressure signals under the operating condition Q/QD=0.15 were analyzed in the time domain and frequency domain respectively. The results suggested that low frequency pressure fluctuations(f/9fn=11.27%) are remarkable and the pressure signal in the stay vanes is not affected by the runner while that in guide vanes is influenced obviously.

Li J.,State Key Laboratory of Hydropower Equipment | Liangyu X.,State Key Laboratory of Hydropower Equipment | Han X.,State Key Laboratory of Hydropower Equipment
Insight: Non-Destructive Testing and Condition Monitoring | Year: 2016

Variations in the surface magnetic field induced by the geomagnetic field in the presence of applied load can potentially be used to evaluate the stress state of ferromagnetic materials. In the present work, the focus is on the effect of applied load on the bulk and local surface magnetic fields. Measurements of the normal component Hp(y) of the surface magnetic field were performed during tensile tests. The results show that remarkable changes in the surface magnetic field occur well before yield. Based on the magneto-mechanical effect and the magneto-plastic model, the effects of applied load on the surface magnetic field in the elastic and plastic regimes are discussed.

Zhou W.-J.,Zhejiang University | Wei X.-S.,Zhejiang University | Wei X.-Z.,State Key Laboratory of Hydropower Equipment | Wang L.-Q.,Zhejiang University
Journal of Zhejiang University: Science A | Year: 2014

Based on the finite element method (FEM) and the Lagrange equation, a novel nonlinear model of a double disc rotor-seal system, including the coupled effects of the gravity force of the discs, Muszynska's nonlinear seal fluid dynamic force, and the mass eccentricity of the discs, is proposed. The fourth order Runge-Kutta method is applied to solve the motion equations of the system and numerically determine the vibration response of the center of the discs. The dynamic behavior of the system is analyzed using bifurcation diagrams, time-history diagrams, axis orbit diagrams, Poincaré maps, and amplitude spectrums. With the rotor speed increasing, the system presents rich forms including periodic, multi-periodic, quasi-periodic, and chaotic motion. We also discuss the effects of the distance between the two discs, the mass of the discs, seal clearance, seal length, and seal drop pressure on the dynamic behavior of the system. The numerical results demonstrate that a symmetrical disc structure, small disc mass, proper seal clearance, long seal length and high seal drop pressure can enhance the stability of a double disc rotor-seal system. The results provide a theoretical foundation for the design of multi-stage sealing systems. © 2014 Zhejiang University and Springer-Verlag Berlin Heidelberg.

Li R.,State Key Laboratory of Hydropower Equipment
Shuili Fadian Xuebao/Journal of Hydroelectric Engineering | Year: 2015

This paper describes the end-surface cavitation of a Francis runner, analyzes the cause for this type of cavitation, and suggests some precautions. A brief discussion on the similarity between prototype and model turbines is given. © Copyright.

Guo L.,Zhejiang University | Liu J.,China Aerospace Science and Technology Corporation | Wang L.,Zhejiang University | Qin D.,State Key Laboratory of Hydropower Equipment | Wei X.,State Key Laboratory of Hydropower Equipment
Science China Technological Sciences | Year: 2014

Pressure fluctuation at the vaneless space and vanes passages is one of the most important problems for the stable operation of a pump turbine. The fluctuation appears in any operating condition. Much research has been done on the pressure fluctuation of hydraulic machinery. However, the details of pressure fluctuation propagation of the pump turbine at the pump mode have not been revealed. The modern pump turbine with high water head requires the runner to be "flat", which would induce pressure fluctuation more easily than the low head pump turbine. In this article, a high head pump turbine model is used as the research object. As the pressure fluctuation at off-design point is more serious than at the design point, the low head condition is chosen as the research condition. Pressure fluctuation at the vaneless space and vanes passages is predicted by the computational fluid dynamics method based on k-ω shear stress transport model. The experiment conducted on the test rig of the Harbin Institute of Large Electrical Machinery is used to verify the simulation method. It proves that the numerical method is a feasible way to research the fluctuation under this operating condition. The pressure fluctuation along the passage direction is analyzed at time and frequency domains. It is affected mainly by the interaction between the runner and vanes. In the circumferential direction, the influence of the special stay vane on the pressure fluctuation is got. The amplitude in the high-pressure side passage of that vane is lower than that in the other side. The study provides a basic understanding of the pressure fluctuation of a pump turbine and could be used as a reference to improve the operation stability of it. © 2014 Science China Press and Springer-Verlag Berlin Heidelberg.

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