Investigation of a Francis turbine during speed variation: Inception of cavitation

RENEWABLE ENERGY

卷:166

Article

Trivedi, Chirag¹  Iliev, Igor¹  Dahlhaug, Ole Gunnar¹  Markov, Zoran²  Engstrom, Fredrik^3,4  Lysaker, Henning⁵ 

[1] NTNU Norwegian Univ Sci & Technol, Waterpower Lab, N-7491 Trondheim, Norway

[2] Ss Cyril & Methodius Univ, Fac Mech Engn, Skopje 1000, North Macedonia

[3] Vattenfall AB, Aurorum 12, S-97177 Lulea, Sweden

[4] Lulea Univ Technol, Div Fluid & Expt Mech, S-97187 Lulea, Sweden

[5] Rainpower Norge AS, SP Andersens Veg 7, N-7031 Trondheim, Norway

关键词: Cavitation;    CFD;    Energy;    Hydropower;    Turbine;    Variable-speed;   

DOI  :  10.1016/j.renene.2020.11.108

来源: Elsevier

【 摘 要 】

Variable-speed operation of a hydro turbine is considered as an alternative option to meet fluctuating energy demand as it allows high-ramping rate. Cavitation can be a limiting factor to utilize the variable speed technology at full potential in a hydro power plant. This work investigates the cavitation characteristics and unsteady pressure fluctuations as turbine ramps up, to meet the energy demand. The investigated Francis turbine consists of 15 blades and 15 splitters, and the reference diameter is 0.349 m. Numerical model of complete turbine is prepared and hexahedral mesh is created. Rayleigh Plesset algorithm is activated for cavitation modelling. Available experimental data of model acceptance test are used to prescribe boundary conditions, and to validate the numerical results at distinct points. Transient behaviour of the cavitation is studied, and the results are quite interesting. At certain time instants, the cavitation effect is extremely predominant, and as a result of cavitation bubble bursts, the amplitudes of pressure fluctuations are significantly high. (C) 2020 The Author(s). Published by Elsevier Ltd.

【 授权许可】

Free