International Journal of Fluid Machinery and Systems

Korean Society for Fluid machinery (한국유체기계학회)
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Uncertainty in Operational Modal Analysis of Hydraulic Turbine Components

  • Gagnon, Martin (Department of Mechanical Engineering, Ecole de technologie superieure) ;
  • Tahan, S.-Antoine (Department of Mechanical Engineering, Ecole de technologie superieure) ;
  • Coutu, Andre (Andritz-Hydro Ltd)
  • Accepted : 2009.05.27
  • Published : 2009.12.01
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Abstract

Operational modal analysis (OMA) allows modal parameters, such as natural frequencies and damping, to be estimated solely from data collected during operation. However, a main shortcoming of these methods resides in the evaluation of the accuracy of the results. This paper will explore the uncertainty and possible variations in the estimates of modal parameters for different operating conditions. Two algorithms based on the Least Square Complex Exponential (LSCE) method will be used to estimate the modal parameters. The uncertainties will be calculated using a Monte-Carlo approach with the hypothesis of constant modal parameters at a given operating condition. In collaboration with Andritz-Hydro Ltd, data collected on two different stay vanes from an Andritz-Hydro Ltd Francis turbine will be used. This paper will present an overview of the procedure and the results obtained.

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References

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