Experimental Investigation of Rotor Vibration Induced by Rotor-Stator Rubbing With Soft Coating

Abstract

Abstract Rotor-stator rubbing is common in aero-engines, and the resulting vibration characteristic is affected by the coating material and the structure of rotor and stator. Partial rubbing between a soft rubber coated casing and seal labyrinth teeth on a thin-shell rotating drum is investigated. The vibration response of the drum and the rear end of the rotor is analyzed from the perspective of time, frequency and hologram domains. The time waveform of the drum is significantly distorted by rubbing, resulting in strong fluctuations of the vibration amplitude. The rubbing is observed within a very short time, followed by recovery of stable vibration of the rotor. Rotor-stator coupling vibration is excited by this studied rubbing. The natural frequencies corresponding to the pith diameter vibration modes both of the drum and the casing can be observed in the vibration spectrums of the drum. The synchronous forward whirl is suppressed to some extend by rubbing, whereas the synchronous backward whirl is enhanced. The smaller the whirl amplitude ratio between the forward whirl and backward whirl, the more serious the rubbing. The vibration at the rotor rear end is hardly affected.