A Review of Morton Effect: From Theory to Industrial Practice

The Morton effect (ME) is known to cause spiral vibrations of rotors supported by fluid lubricant bearings when there is significant differential heating at rotor journals. The root cause of ME is accumulative asymmetric heating brought on by the viscous shearing effect of the bearing lubricant, mainly during synchronous vibrations. The thermal nature of the cause together with the symptoms of spiral vibrations make ME a thermal-induced instability. This article provides an in-depth review of the ME. It starts with a general introduction and assessment of the significance of ME, noting its widespread nature. Subsequently, key findings are introduced about general ME mechanisms, including the important relationship between journal orbits and the hot spot. The circumstances and typical symptoms of ME-induced instability are summarized and followed by a discussion of the critical issues to be tackled in both the theoretical analysis and the experimental techniques regarding ME phenomenon. Lastly, this article includes a discussion about the inconsistencies found in the literature regarding topics such as the excitation models for the thermal bow.