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Entropy production analysis for hump characteristics of a pump turbine model

  • Fluid and Power Machinery
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Abstract

The hump characteristic is one of the main problems for the stable operation of pump turbines in pump mode. However, traditional methods cannot reflect directly the energy dissipation in the hump region. In this paper, 3D simulations are carried out using the SST k-ω turbulence model in pump mode under different guide vane openings. The numerical results agree with the experimental data. The entropy production theory is introduced to determine the flow losses in the whole passage, based on the numerical simulation. The variation of entropy production under different guide vane openings is presented. The results show that entropy production appears to be a wave, with peaks under different guide vane openings, which correspond to wave troughs in the external characteristic curves. Entropy production mainly happens in the runner, guide vanes and stay vanes for a pump turbine in pump mode. Finally, entropy production rate distribution in the runner, guide vanes and stay vanes is analyzed for four points under the 18 mm guide vane opening in the hump region. The analysis indicates that the losses of the runner and guide vanes lead to hump characteristics. In addition, the losses mainly occur in the runner inlet near the band and on the suction surface of the blades. In the guide vanes and stay vanes, the losses come from pressure surface of the guide vanes and the wake effects of the vanes. A new insight-entropy production analysis is carried out in this paper in order to find the causes of hump characteristics in a pump turbine, and it could provide some basic theoretical guidance for the loss analysis of hydraulic machinery.

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Authors

Corresponding author

Correspondence to Hongjie Wang.

Additional information

Supported by National Key Technology R&G Program (Grant No. 2012BAF03B01-X), and Innovative Research Groups of National Natural Science Foundation of China (Grant No. 51121004)

LI Deyou, born in 1986, is currently a PhD candidate at School of Energy Science and Engineering, Harbin Institute of Technology, China. He received his bachelor and master degree from Harbin Institute of Technology, China, in 2010 and 2012, respectively. His research interests include numerical simulation and experimental investigation of hydraulic machinery, such as pump turbine, turbine and pump; modeling and simulation of hydraulic system control, and testing technology of hydraulic machinery.

GONG Ruzhi, born in 1977, is currently a lecturer at School of Energy Science and Engineering, Harbin Institute of Technology, China. He received his PhD degree on engineering thermal physics from Harbin Institute of Technology, China, in 2013.

WANG Hongjie, born in 1962, is currently the Vice President and a professor at School of Energy Science and Engineering, Harbin Institute of Technology, China.

XIANG Gaoming, born in 1992, is currently a master candidate at School of Energy Science and Engineering, Harbin Institute of Technology, China.

WEI Xianzhu, born in 1966, is currently the Vice Chief Designer and the Director of Hydraulic Turbine Research Department at Harbin Institute of Large Electrical Machinery, Harbin, China. And also, he is a part time professor at School of Energy Science and Engineering, Harbin Institute of Technology, China.

QIN Daqing, born in 1965, is currently the Vice Chief Engineer and the Vice president at Harbin Institute of Large Electrical Machinery, China. And also, he is a part time professor at School of Energy Science and Engineering, Harbin Institute of Technology, China.

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Li, D., Gong, R., Wang, H. et al. Entropy production analysis for hump characteristics of a pump turbine model. Chin. J. Mech. Eng. 29, 803–812 (2016). https://doi.org/10.3901/CJME.2016.0414.052

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  • DOI: https://doi.org/10.3901/CJME.2016.0414.052

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