Solving the runner blade crack problem for a Francis hydro-turbine operating under condition-complexity

Di Zhu, Ran Tao, Ruofu Xiao and Litan Pan

Renewable Energy, 2020, vol. 149, issue C, 298-320

Abstract: Runner blade crack is a problem that affects the operation security of hydro-turbines. In this study, penetrating cracks were found by inspection on the runner blade of a Francis turbine near hub and shroud on trailing-edge. To solve this problem, prototype test was conducted to find the conditions under strong hydraulic instabilities. The turbine vibration region was classified based on the test and found mainly at small guide vane opening angles or low-head high-load conditions. In these regions, vibration was strong and the numerical-predicted flow regime was disordered. Analyzed by fluid-solid interaction method, stress concentrations were found on the blade-hub and blade-shroud connections on trailing-edge. By excluding the influence of resonance, the runner blade crack problem was found as the combination of concentrating static stress, hydraulic excited pulsating stress and residual stress. Triangle-blocks, which were helpful for eliminating the concentrating static stress, were welded on the blades after cutting-off the old crack sites. Polishing and buffing were conducted for reducing potential residual stress. After a long-time re-operation, the improved runner was found without runner blade cracks. Prototype re-testing showed no impacts on the efficiency. This study provided a good solution for the Francis turbine runner blade crack problem under condition-complexity.

Keywords: Francis turbine; Runner blade cracks; FSI simulation; Triangle-blocks welding; Operation-region division (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (8)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0960148119319299
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:renene:v:149:y:2020:i:c:p:298-320

DOI: 10.1016/j.renene.2019.12.057

Access Statistics for this article

Renewable Energy is currently edited by Soteris A. Kalogirou and Paul Christodoulides

More articles in Renewable Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().