Flow Characteristics Analysis of Load Rejection Transition Process in Pumped Storage Unit Based on Cavitation Model

Li, Q.; Xin, L.; Yao, L.; Zhang, S.

doi:10.47176/jafm.17.9.2546

Flow Characteristics Analysis of Load Rejection Transition Process in Pumped Storage Unit Based on Cavitation Model

Document Type : Regular Article

Authors

¹ School of Energy and Power Engineering, Lanzhou University of Technology 1, Lanzhou, Gansu, 730050, China

² Key Laboratory of Fluid Machinery and Systems 2, Lanzhou, Gansu, 730050, China

³ Tianjin Key Laboratory of Hydroelectric Power Generating Equipment 3, Tianjin, 300000, China

10.47176/jafm.17.9.2546

Abstract

Concerning dual-carbon applications, establishing a new energy-dominated power system to achieve carbon peaking and carbon neutrality objectives is imperative. Pumped storage units excel in this context, owing to their unique advantages. During the load-shedding process of the pump turbine, the intricate flow patterns and cavitation phenomena substantially influence the flow field. This study introduces a cavitation model to perform numerical simulations of load rejection processes in pumped storage power plants, aiming to thoroughly investigate the impact of cavitation phenomena on the units. The results indicate that as the rotational speed increases, the dynamic and static interference within the no-blade region becomes notable, resulting in pressure pulsations within the guide vane region and exacerbating structural deformation and fatigue failures. Moreover, deviations from the designated operational point disrupt the symmetry of the flow field, leading to irregular changes in radial forces. Accounting for the mass disturbance and changes in wave velocity attributable to a cavitation phase transition, pressure fluctuation amplitude increases within the draft tube, consequently engendering complex flow phenomena. These findings offer indispensable guidance for the optimal design and safe operation of pump turbines within new power systems.

Keywords

Main Subjects

Turbomachinary

References

Chen, D., & Xie, H. (2001). Internal flow characteristics of low specific speed pump-turbine in "S" characteristic region. Journal of Hydraulic Engineering, 2001(2), 76-78+84. https://doi.org/10.3321/j.issn:0559-9350.2001.02.014

Fu, X., & Li, D. (2018). Dynamic instability of a pump-turbine in load rejection transient process. Science China Technological Sciences, 61(11), 1765-1775. https://doi.org/10.1007/s11431-017-9209-9

Goyal, R., & Gandhi, B. K. (2018). Review of hydrodynamics instabilities in Francis turbine during off-design and transient operations. Renewable Energy, 116: 697-709https://doi.org/10.1016/j.renene.2017.10.012

Hasmatuchi, V., Farhat, M., & Roth S. (2011). Experimental evidence of rotating stall in a pump-turbine at off design conditions in generating mode. Journal of Fluids Engineering, 133(5), 623-635. https://doi.org/10.1115/1.4004088

Kubota, T., & Kushimoto, S. (1978). Visual observation of internal flow through high-head pump-turbine. Fuji Electric Review, 26(4), 133-144. https://doi.org/10.13245/j.hust.201118

Le, Z., Xiao, Y., & Gui, Z. (2018). Analysis of pressure pulsation and internal flow characteristics in pump-turbine at extremely low guide vane opening in reverse pump mode. Journal of Hydraulic Engineering, 49(12), 1541-1549. https://doi.org/10.13243/j.cnki.slxb.20180794

Li, B. (2012). Characteristics study of pump-turbine in reverse pump mode. Technology Wind, 2012, (14), 155. https://doi.org/10.19392/j.cnki.1671-7341.2012.14.127

Li, Q., Chen, X., & Cai, T. (2021). Study on influence of asynchronous guide vane on unit characteristics under different arrangement modes. Acta Energiae Solaris Sinica, 42(8), 23-31. (In Chinese). https://doi.org/10.19912/j.0254-0096.tynxb.2019-0769

Li, Q., Zhang, Z., & Li, R. (2018). Pressure pulsation characteristics in the bladeless area of a pump-turbine with MGV device. Journal of Drainage and Irrigation Machinery Engineering, 2018(12). https://doi.org/10.3969/j.issn.1674 -8530.16.0318

Li, W., Li, Z., & Han, W. (2023). Time-mean equation and multi-field coupling numerical method for low-Reynolds-number turbulent flow in ferrofluid. Physics of Fluids, 35(12), 125145. https://doi.org/10.1063/5.0179961

Liu, J., Li, Z., & Wang, L. (2011). Numerical Simulation of the Transient Flow in a Radial Flow Pump during Stopping Period, Journal of Fluids Engineering, 133 (11). 111101-1-7. https://doi.org/10.1115/1.4005137

Luo, X. (2022). Study on the influence of "S" characteristics of pumped storage units on load rejection transition process [D, Huazhong University of Science and Technology]. https://doi.org/10.27157/d.cnki.ghzku.2022.004940

Mao, X., Chen, D., & Wang, Y. (2021). Investigation on optimization of self-adaptive closure law for load rejection to a reversible pump turbine based on CFD. Journal of Cleaner Production, 283 (0), 124739-124739. https://doi.org/10.1016/j.jclepro.2020.124739

Pejovic, S., Krsmanovic, L., & Jemcov, R. (1976). Unstable operation of high-head reversible pump-turbines. IAHR’s 8th Symposium, Leningrad, USSR, 1976. https://doi.org/10.3969/j.issn.2096-093X.1976.05.039

Peng, Y., Liu, C., & Gao, Y. (2021). Influence of characteristic curve and runner selection on transition process of pumped storage power station, Hydropower and Pumped Storage, 7(5), 70-75. (In Chinese). https://doi.org/10.3969/j.issn.2096-093X.2021.05.011

Qian, Z., Zheng, B., & Yang, J. (2008). Effects of different guide vanes on pressure pulsation in hydro turbines. Journal of Wuhan University, 41(6), 51-54. https://doi.org/10.3969/j.issn.1021-8952.2008.06.037

Wan, Z. (2023). Optimization of the closing law of francis turbine guide vanes and inverse prediction analysis of the transition process [D , Nanchang University]. https://doi.org/10.27232/d.cnki.gnchu.2023.003849

Xiao, Y., & Xiao, R. (2014). Transient simulation of a pump-turbine with misaligned guide vanes during turbine model start-up. Acta Mechanica Sinica, 30(5), 646-655. https://doi.org/10.1007/s10409-014-0061-6

Xu, L., Peng, Y., & Tang W. (2022). Pump turbine in zone state S characteristics and pressure fluctuation research. Water dynamics research and progress in A series, 2022 (02), 213-225. https://doi.org/10.16076/j.cnki.cjhd.2022.02.009

Zeng, W., Yang, J., & Hu, J. (2017) Pumped storage system model and experimental investigations on S-induced issues during transients. Mechanical Systems and Signal Processing, 90: 350-364. https://doi.org/10.1016/j.ymssp.2016.12.031

Zhai, L., Wang Z., & Li Z. (2016). TEHD analysis of a bidirectional thrust bearing in a pumped storage unit. Industrial Lubrication and Tribology, 68(3). 315-324. https://doi.org/10.1108/ilt-07-2015-0092

Zhang, Y., Zheng, X., & Li, J. (2019) Experimental study on the vibrational performance and its physical origins of a prototype reversible pump turbine in the pumped hydro energy storage power station. Renewable Energy, 130. pp. 667-676. https://doi.org/10.1016/j.renene.201

Zuo, Z., Fan, H., & Liu, S. (2015). S-shaped characteristics on the performance curves of pump-turbines in turbine mode - A review. Renewable & Sustainable Energy Reviews. 60(0), 836-851. https://doi.org/10.1016/j.rser. 2015.12.312.