Measurement of the bending vibration frequencies of a rotating turbo wheel using an optical fibre reflective sensor

An optical fiber reflective sensor was used to analyze the vibrations of a rotating turbo wheel up to 20,400 rpm. The measured signal required correction because of the natural unevenness of the turbo wheel and because of the variable deflection. Because the turbo wheel was rotating, the signal became distorted and so we used a special method to extract the frequencies of the vibrations from the power spectra. The analysis showed increased intensity of the first three natural frequencies with an increased speed of rotation. The experimental results match very well with those obtained by numerical computation. (Author)