Investigation of a Francis turbine during speed variation: Inception of cavitationShow others and affiliations
2021 (English)In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 166, p. 147-162Article in journal (Refereed) Published
Abstract [en]
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 fully capacity 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 Model 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.
Place, publisher, year, edition, pages
Elsevier, 2021. Vol. 166, p. 147-162
Keywords [en]
Cavitation, cfd, energy, hydropower, turbine, variable-speed
National Category
Fluid Mechanics
Research subject
Fluid Mechanics
Identifiers
URN: urn:nbn:se:ltu:diva-81829DOI: 10.1016/j.renene.2020.11.108ISI: 000608455000014Scopus ID: 2-s2.0-85097042852OAI: oai:DiVA.org:ltu-81829DiVA, id: diva2:1506326
Funder
EU, Horizon 2020, 764011
Note
Validerad;2021;Nivå 2;2021-01-01 (johcin)
2020-12-032020-12-032025-02-09Bibliographically approved