Evaluation of System Damping Using Run Down Time for Rotors Mounted on Fluid Film Bearings – A New Technique~?

摘要

Vibration measurements and their analyses in determining the performance of a rotor bearing system is a very old technique with latest modifications. One such tool is to study the behavior of a rotating member when the power supply is cutoff. This is popularly known as run down behavior. It is a transient process occurring during shut down of rotors, provide lot of information about their dynamic behavior. Also, rundown time is a direct measure of damping in the rotating system. The rate of energy dissipation and rundown time are inversely proportional. The exponential decay of vibrational energy can also be related to rundown behavior. This approach is made use off here to derive system damping for rotors mounted on bearings with different geometries. The experimentally recorded run down plots are used for the purpose. Also, this new technique is applied to certain case examples reported in the literature.