The goal of this thesis is to develop, validate, and apply reliability assessment methodologies to estimate the probability of fatigue cracking in hydroelectric runner blades. In the recent years, the growing influence of intermittent energy source, such as wind turbines, on hydroelectric facility operation force hydroelectricity producer to change their operation scenarios in order to account for this new variability. This new variability tends to augment the risk of failure which renders difficult maintenance planning and the achievement of the desired level of reliability. Hence, both the manufacturer and the operator of hydroelectric turbines need tools to evaluate the influence of these changes on the reliability of their structure.
The results presented in this thesis cover the following aspects: Loading characterization, damage modeling, and reliability assessment. After a rapid introduction, a literature review gives an overview of research made in each field. Next, in the first chapter, the loading of runner blades is studied. Loading generated by transient events such as turbine startups are modeled using stochastic models. Our results show that such models are particularly useful in case where limited data is available to estimate the variability of such events. In Chapter 2, we propose a limit state for the HCF onset on turbine runner blades. This limit state combined with probabilistic method render possible fatigue reliability and likelihood of crack detection estimate. Subsequently in Chapter 3, our reliability model is applied using the data gathered from one of Hydro-Québec’s power plant. Our objective was to evaluate the influence of loading assumptions. As a result, loading spectra are proposed with different level of simplification in order to determine the minimal number of parameters necessary to adequately estimate the reliability.
Finally, in the conclusion, we discuss the contributions to the reliability assessment of hydroelectric turbine runner blades of the work presented in this thesis. Furthermore, at the same time, we highlight new and emerging research opportunities uncovered during our research activities.
| Date | 3 Jul 2013 |
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| Original language | French |
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| Awarding Institution | - École de technologie supérieure
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| Supervisor | Antoine Tahan (Supervisor) & Philippe Bocher (Co-supervisor) |
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Gagnon, M. (Author),
Tahan (Supervisor) &
Bocher (Co-supervisor),
3 Jul 2013Student thesis: Doctoral thesis › Doctorate in Engineering: Engineering