THE VIBRATION OF AN AEROENGINE ROTOR INCORPORATING 2 SQUEEZE-FILM DAMPERS

Virtually all previous research on the squeeze-flint damping of rotor assemblies has considered the use of only one damper. However, many ae ro-engine rotor assemblies have at feast two dampers and the interplay between them is an important factor in the overall vibration performa nce of the rotor. The purpose of this paper is to report results on a test facility which simulates the rotor of an aero-engine of the size used to power an executive jet. It draws general conclusions on the ap plication of two squeeze-film dampers (SFDs) to such a rotor, while in the process qualitatively validating a suggested theoretical model of the SFD. The test facility is a three bearing rigid rotor assembly in corporating two sprung bearing supports, each in series with a weakly sealed squeeze-film damper. A range of practical configurations with d ifferent SFD static misalignments is studied. Non-linear jump phenomen a and subharmonic resonances are demonstrated both experimentally and theoretically for a range of rotor unbalance. The paper is concerned w ith predicting and measuring rotor-centre responses and vibration orbi ts and drawing conclusions that are relevant to the designer. It forms a complement to a previous paper (1) in which spectrum analyses of vi bration signatures were made.