Analysis of bulb turbine hydrofoil cavitation

Podnar, Andrej (author), Hočevar, Marko (author), Novak, Lovrenc (author), Dular, Matevž (author)

The influence of a bulb runner blade hydrofoil shape on flow characteristics around the blade was studied. Experimental work was performed on a bulb turbine measuring station and a single hydrofoil in a cavitating tunnel. In the cavitation tunnel, flow visualization was performed on the hydrofoil's suction side. Cavitation structures were observed for several cavitation numbers. Cavitation was less intense on the modified hydrofoil than on the original hydrofoil, delaying the cavitation onset by several tenths in cavitation number. The results of the visualization in the cavitation tunnel show that modifying the existing hydrofoil design parameters played a key role in reducing the cavitation inception and development, as well as the size of the cavitation structures. A regression model was produced for cavitation cloud length. The results of the regression model show that cavitation length is dependent on Reynolds's number and the cavitation number. The coefficients of determination for both the existing and modified hydrofoils were reasonably high, with R$^2$ values above 0.95. The results of the cavitation length regression model also confirm that the modified hydrofoil exhibits improved the cavitation properties.

• Language: English
• Keywords: hydrofoil, bulb turbine, bulb turbine runner, cavitation, flow visualization, cavitation tunnel, regression model
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2021
• Number of pages: 18 str.
• Numbering: Vol. 11, iss. 6, art. 2639
• PID: 20.500.12556/RUL-125678
• UDC: 519.8:532.528(045)
• ISSN on article: 2076-3417
• DOI: 10.3390/app11062639
• COBISS.SI-ID: 56988419
• Publication date in RUL: 01.04.2021

Record is a part of a journal

• Title: Applied sciences
• Shortened title: Appl. sci.
• Publisher: MDPI
• ISSN: 2076-3417
• COBISS.SI-ID: 522979353

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 16.03.2021

Secondary language

• Language: Slovenian
• Keywords: hidrodinamski profil, cevna turbina s hruško, kavitacija, vizualizacija toka, kavitacijski model, regresijski model

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0401
• Name: Energetsko strojništvo