Numerical Study of the Oil Whip Phenomenon in Elastic Shafts Supported by Hydrodynamic Journal Bearings
DOI:
https://doi.org/10.70567/mc.v41i14.72Keywords:
Lubrication, Vibrations, Resonance, Journal BearingsAbstract
Oil whirl consists of an instability of the lubricating film of the hydrodynamic bearing due to a loss of its load capacity under low load conditions. This instability produces a sub-synchronous vibration at half the shaft rotation speed. When the rotation reaches twice the natural frequency, the vibration frequency remains constant and close to the value of the first resonance frequency. This last phenomenon is called oil whip and is detrimental to rotor life. In this work, the behavior of a one-dimensional elastic rotor is analyzed using the Finite Element Method. Literature cases with unbalanced discs and masses are analyzed to determine their effects on shaft instability. The results obtained from using linear and nonlinear dynamic models for the representation of the hydrodynamic bearings are also compared.
References
Birembaut Y. y Peigney J. Prediction of dynamic properties of rotor supported by hydrodynamic bearings using the finite element method. Computers & Structures, 12(4):483-496, 1980. ISSN 0045-7949. https://doi.org/10.1016/0045-7949(80)90124-8
de Castro H.F., Cavalca K.L., y Nordmann R. Whirl and whip instabilities in rotor-bearing system considering a nonlinear force model. Journal of Sound and Vibration, 317(1):273-293, 2008. ISSN 0022-460X. https://doi.org/10.1016/j.jsv.2008.02.047
Friswell M., Penny J., Garvey S., y Lees A. Dynamics of Rotating Machines. Cambridge University Press, 2010. ISBN 9780521850162. https://doi.org/10.1017/CBO9780511780509
Hamrock B. Fundamentals of fluid film lubrication. McGraw-Hill, 1994.
Khonsari M. y E.R. B. Applied tribology: bearing design and lubrication, 3rd edition. John Wiley & Sons Ltd, 2017. https://doi.org/10.1002/9781118700280
Ma H., Li H., Niu H., Song R., y Wen B. Numerical and experimental analysis of the first-and second-mode instability in a rotor-bearing system. Archive of Applied Mechanics, 84, 2014. https://doi.org/10.1007/s00419-013-0815-9
Muszynska A. Whirl and whip rotor/bearing stability problems. Journal of Sound and Vibration, 110(3):443-462, 1986. ISSN 0022-460X. https://doi.org/10.1016/S0022-460X(86)80146-8
Muszynska A. Stability of whirl and whip in rotor/bearing systems. Journal of Sound and Vibration, 127(1):49-64, 1988. ISSN 0022-460X. https://doi.org/10.1016/0022-460X(88)90349-5
Nelson H.D. y McVaugh J.M. The Dynamics of Rotor-Bearing Systems Using Finite Elements. Journal of Engineering for Industry, 98(2):593-600, 1976. https://doi.org/10.1115/1.3438942
Ocvirk F. Short-bearing approximation for full jounral bearings. Cornell University, 10, 1952.
Palavecino J., Cavalieri F., y Márquez Damián S. A second-order in time and space model to solve the coupled reynolds-rayleigh-plesset equations for the dynamics of cavitated hydrodynamic journal bearings. Tribology International, 192:109206, 2024. ISSN 0301-679X. https://doi.org/10.1016/j.triboint.2023.109206
Pinkus O. y B. S. Theory of hydrodinamic lubrication. Mc-Graw Hill, 1961.
Szeri A. Fluid film lubrication, 2nd edition. Cambridge University Press, 2011. https://doi.org/10.1017/CBO9780511782022
Öchsner A. y Merkel M. One-Dimensional Finite Elements. Springer, 2018. ISBN 978-3-319-75144-3. doi:10.1007/978-3-319-75145-0. https://doi.org/10.1007/978-3-319-75145-0
Downloads
Published
Issue
Section
License
Copyright (c) 2024 Argentine Association for Computational Mechanics
This work is licensed under a Creative Commons Attribution 4.0 International License.
This publication is open access diamond, with no cost to authors or readers.
Only those papers that have been accepted for publication and have been presented at the AMCA congress will be published.
