Dynamics of a small gap gas lubricated bearing with Navier slip boundary conditions

Bailey, N. Y.; Hibberd, Stephen; Power, H.

Abstract

A gas lubricated bearing model is derived which is appropriate for a very small bearing face separation by including velocity slip boundary conditions and centrifugal inertia effects. The bearing dynamics are examined when an external harmonic force is imposed on the bearing due to bearing begin situated within a larger complex dynamical system. A compressible Reynolds equation is formulated for the gas film which is coupled to the bearing structure through an axial force balance where the rotor and stator correspond to spring-mass-damper systems. Surface slip boundary conditions are derived on the bearing faces, characterised by the slip length parameter. The coupled bearing system is analysed using a stroboscopic map solver with the modified Reynolds equation and structural equations solved simultaneously. For a sufficiently large forcing amplitude a apping motion of the bearing faces is induced when the rotor and stator are in close proximity. The minimum bearing gap over the time period of the external forcing is examined for a range of bearing parameters.

Citation

Bailey, N. Y., Hibberd, S., & Power, H. (2017). Dynamics of a small gap gas lubricated bearing with Navier slip boundary conditions. Journal of Fluid Mechanics, 818, 68-99. https://doi.org/10.1017/jfm.2017.142

• Journal Article Type: Article
• Acceptance Date: Feb 8, 2017
• Online Publication Date: Mar 28, 2017
• Publication Date: 2017-05
• Deposit Date: Mar 6, 2017
• Publicly Available Date: Mar 28, 2017
• Journal: Journal of Fluid Mechanics
• Print ISSN: 0022-1120
• Electronic ISSN: 1469-7645
• Publisher: Cambridge University Press
• Peer Reviewed: Peer Reviewed
• Volume: 818
• Pages: 68-99
• DOI: https://doi.org/10.1017/jfm.2017.142
• Public URL: https://nottingham-repository.worktribe.com/output/852700
• Publisher URL: https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/dynamics-of-a-small-gap-gas-lubricated-bearing-with-navier-slip-boundary-conditions/5132AED92CA4F75D37D7096BA161E2BF
• Additional Information: License: © 2017 Cambridge University Press