Life assessment and extension for gas turbine blades

Pertti Auerkari, Jorma Salonen, Juhani Rantala, Sari Mäkinen, Ilkka Karvonen, Heikki Tanttari, Pekka Kangas, Jukka Taattola

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

    Abstract

    Gas turbine blades operate under severe loading conditions, and for satisfactory service must be designed to withstand multiple damage mechanisms. On the other hand, if the assumptions on the future service are sufficiently conservative or actual service conditions more benign than foreseen, there is potential for blade life extension. This generally does not justify fully omitting intermediate inspections, as intervening damage by e.g. overheating or foreign objects is not excluded, and restoring coatings or other repairs could be needed. Nevertheless, a significant extension to the time of final replacement can be possible. In this work, example cases are used to highlight the technical challenges and results of blade life extension. Such aspects include assessment of in-service stress and temperature histories, interpretation of condition assessment, and materials performance. The example cases refer to ex-service blade samples extracted at the time approximately corresponding to the nominal blade life as defined by the engine supplier. Both land based and aircraft turbines are considered, and in spite of the differences in design and service profiles, similarities can be pointed out. The results for the example cases generally suggest significant potential for life extension, for reasons related to the case-specific service histories.
    Original languageEnglish
    Title of host publicationBaltica VIII
    Subtitle of host publicationLife Management and Maintenance for Power Plants
    Place of PublicationEspoo
    PublisherVTT Technical Research Centre of Finland
    Pages117-127
    Volume2
    ISBN (Electronic)978-951-38-7594-7
    ISBN (Print)978-951-38-7593-2
    Publication statusPublished - 2010
    MoE publication typeB3 Non-refereed article in conference proceedings
    EventBALTICA VIII - International Conference on Life Management and Maintenance for Power Plants - Helsinki-Stockholm, Finland
    Duration: 18 May 201020 May 2010

    Publication series

    SeriesVTT Symposium
    Number265
    ISSN0357-9387

    Conference

    ConferenceBALTICA VIII - International Conference on Life Management and Maintenance for Power Plants
    CountryFinland
    CityHelsinki-Stockholm
    Period18/05/1020/05/10

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    Auerkari, P., Salonen, J., Rantala, J., Mäkinen, S., Karvonen, I., Tanttari, H., Kangas, P., & Taattola, J. (2010). Life assessment and extension for gas turbine blades. In Baltica VIII: Life Management and Maintenance for Power Plants (Vol. 2, pp. 117-127). VTT Technical Research Centre of Finland. VTT Symposium, No. 265