Guide Vane Vibrations Caused by Wakes and Blower Noise—Part 2: Transferability From the Model to the Prototype

Abstract

Model tests were carried out on vibrations of guide vanes induced by wakes and noise. The results will be compared with the measurements on the prototype. It will be shown that the modeling law applies well for the wake-induced vibration. But for the noise-excited vibration, the model test with the loudspeaker noise gave too high a level of the dynamic stress compared with that in the prototype excited by the blower noise. This deviation can be attributed to the unsteady phase relationship of the noise generated by the turbomachinery. The acoustic resonances in the channels will be investigated both theoretically and experimentally. A damping of these resonances can be achieved by inserting cross plates into a part of the channel. The mechanical vibration of a turning blade can only be severely excited by the noise, as long as an acoustic resonance prevails in a neighboring channel near the corresponding frequency.