Diagnostics of Turbine Blades, Based on Estimation of Frequency Response Function

• Main Authors: Kotkowski Jerzy, Rokicki Edward, Lindstedt Paweł, Spychała Jarosław, Perczyński Jerzy, Karbowiak Hieronim
• Format: Article
• Language: English
• Published: Sciendo 2021-06-01
• Series: Journal of KONBiN
• Subjects: modal analysis; blade vibration; frequency response; resonance; bode plot; vibration mode; operating deflection shape; q factor; vibration spectrum; transfer function; frequency response function
• Online Access: https://doi.org/10.2478/jok-2021-0022

The aim of the study is to propose a diagnostics method based on blade’s vibration model in frequency domain. Amplitude spectrum A(ω) and phase spectrum φ(ω) have been experimentally identified which define transfer function G(jω) = P(ω) + jQ(ω) and their real P(ω) and imaginary Q(ω) parts. Transfer function G(jω) and resulting frequency, amplitude, phase characteristics and real P(ω) and imaginary Q(ω) parts are parts of blade’s diagnostics model. Changes in those characteristics are directly related to changes in the technical condition of the blades. It has been noticed that small changes in the technical condition cause large changes in frequency characteristics, which proves their usefulness in the diagnosis process.