A Comparative Study of the Scale Effect on the S-Shaped Characteristics of a Pump-Turbine Unit

Jun-Won Suh, Seung-Jun Kim, Hyeon-Mo Yang, Moo-Sung Kim, Won-Gu Joo, Jungwan Park, Jin-Hyuk Kim and Young-Seok Choi
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Jun-Won Suh: Clean Energy R&D Department, Korea Institute of Industrial Technology, Cheonan 31056, Korea
Seung-Jun Kim: Clean Energy R&D Department, Korea Institute of Industrial Technology, Cheonan 31056, Korea
Hyeon-Mo Yang: Clean Energy R&D Department, Korea Institute of Industrial Technology, Cheonan 31056, Korea
Moo-Sung Kim: Department of Mechanical Engineering, Yonsei University, Seoul 03722, Korea
Won-Gu Joo: Department of Mechanical Engineering, Yonsei University, Seoul 03722, Korea
Jungwan Park: Hydropower Design & Technology Group, Korea Hydro & Nuclear Power Co., Ltd., Daejeon 34101, Korea
Jin-Hyuk Kim: Clean Energy R&D Department, Korea Institute of Industrial Technology, Cheonan 31056, Korea
Young-Seok Choi: Clean Energy R&D Department, Korea Institute of Industrial Technology, Cheonan 31056, Korea

Energies, 2021, vol. 14, issue 3, 1-29

Abstract: S-shaped characteristics in turbine mode are prone to instabilities in associated transient processes. A single value of the speed factor corresponds to multiple values of the discharge factor, having the possibility of changing the operating point among the turbine, turbine brake, and reverse pump modes. Because of this characteristic, the S-shaped curves induce instability in transient processes. Understanding the hydraulic behavior of a turbine on the four-quadrant characteristic is important since it provides detailed performance information through the whole discharge range of the turbine. This study was numerically and experimentally investigated the scale effect on the S-shaped characteristics in the turbine transition region. The four-quadrant characteristic curves (full- and laboratory-scale) in the turbine mode were predicted by numerical simulations. To verify the predicted results, a laboratory-scale experiment was performed in the turbine, turbine brake, and reverse pump modes. Although the full-scale experiment was performed in the normal operating head range, the scale effect can be validated by comparing steady operating points between the two models. Based on the verified results, the internal flow and pressure pulsation characteristics were determined at the operating point in a specific transition region.

Keywords: pump turbine; S-shaped characteristics; transient phenomena; scale effect; numerical analysis; experiment (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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