Oil whip-induced wear in journal bearings

Abstract

This paper investigates the effect of oil whirl and oil whip in fluid film radial bearings due to possible metallic contact. The degree of metallic contact and thereby wear and tear between rotating shafts and bearing bushes is assessed by measuring electric currents through the oil film.

Investigation of rotor dynamics with fluid film instabilities II

“…For a better understanding of the fluid film behaviour in journal bearings and more accurate prediction of rotordynamic characteristics during instabilities a greater focus should be placed on a local observation of the fluid film using optical methods. A dyed oil and a transparent bearing bushing allow a simple visual inspection of the oil film condition (Fan et al, 2011;Robbersmyr at al., 2014). Lin et al (2015) introduced a micro particle imaging velocimetry for the visualization of a flow field in the journal bearing.…”

The visualization of shaft vibration using the algorithm of phase-amplitude data interpolation

“…Thus, the measurement of for example absolute vibrations, apart from general evaluation of the technical state of examined machines, also allows us to identify irregularities in action of their individual components, caused by for instance unbalanced rotors, damaged bearings, gear tooth damage or misaligned couplings. The analysis of different properties of vibration signals -measured as a displacement of the shaft relative to the stationary bearing housing -allows us to identify journal bearings instabilities [13][14][15][16], shafts deformations, cracks or misalignment, unbalance, a rotor-to-stator rubbing on seals and bearings and other disturbances as well.…”

“…Often, when a machine is operating under steady state conditions, the identification of only a form or level of vibrations is not enough for correct classification of its technical state. For most complex technical objects, such as turbogenerators, the identification of changes in their technical condition is possible as a result of the assessment of startup and shutdown characteristics (images), that is created in transient operating conditions [5,7,[13][14][15][16]. Then the comparison is made on the current image (created by the defined space of selected features) with the same image made earlier, when the state machine was recognized as correct.…”