Geometric discontinuities identification in hydrodynamic bearings

Abstract

During the operation of rotating machines, especially during starts and stops, hydrodynamic bearings can be progressively worn down. In order to prevent an irreversible failure condition of the entire rotating system, it is necessary to precisely detect wear, without disconnect or disassemble the system. The wear can cause significant geometric changes in the bearing wall, changing the nominal radial clearance. Therefore, the discontinuities can influence the dynamic characteristics of the bearing. In this context, the main objective of this paper is to present a numerical model that represents both the hydrodynamic bearing and the geometric discontinuities to be identified. The parameters of depth, angular span and angular position, according to the wear model, are adjusted by the comparison of the numerical and experimental unbalance response of the system considering the rising of the backward component due to the bearing anisotropy increasing.