An Operation History Of Fractional Frequency Whirl

Abstract

The problem of a whirling rotor in a high pressure centrifugal compressor and the steps to arrive at a solution are described. Orbit shapes and vibratory motion are illustrated. Vibratory frequency ratios compared to undamped lateral critical speeds and rotor geometry are included. A comparison of different bearing, seal and shaft geometries is presented in terms of the relative aid gained from each. Analytical approaches are briefly reviewed in terms of the support added to selection of component geometries. The significance of operational parameters of speed and pressure on the vibratory behavior are mentioned, and some experience factors generalized for whirl suppression.