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General Information
    • ISSN: 1793-8198
    • Frequency: Quarterly
    • DOI: 10.18178/IJMMM
    • Editor-in-Chief: Prof. K. M. Gupta, Prof. Ian McAndrew
    • Executive Editor: Ms. Cherry L. Chen
    • Abstracting/Indexing: EI (INSPEC, IET), Chemical Abstracts Services (CAS), Engineering & Technology Digital Library,  ProQuest, Crossref, Ulrich's Periodicals Directory, DOAJ, and Electronic Journals Library .
    • E-mail ijmmm@ejournal.net
Editor-in-chief
Prof. Ian McAndrew
Embry Riddle Aeronautical University, UK.
It is my honor to be the editor-in-chief of IJMMM. I will do my best to help develop this journal better.

IJMMM 2016 Vol.4(3): 156-161 ISSN: 1793-8198
DOI: 10.7763/IJMMM.2016.V4.246

Stability Analysis of Herringbone-Grooved Aerodynamic Journal Bearings for Ultra High-Speed Rotations

Norifumi Miyanaga and Jun Tomioka
Abstract—Herringbone-grooved aerodynamic journal bearings are suitable to support a rotating shaft with an ultra high-speed rotation. The aim of this work is to investigate the effect of herringbone-groove geometries on stability characteristics of the bearings, considering the centrifugal growth of the shaft. For this purpose, a parametric study of groove geometry is presented. The pressure in a lubricant air film is governed by the compressive lubrication equation based on the Narrow Groove Theory. The dynamic coefficients of the bearing system are calculated using the linear perturbation method. The threshold speed of whirl instability was determined by applying the Routh-Hurwitz criterion to the characteristic equation of the bearing system, and then the stability chart were drawn. The validity of this analysis was proved by the comparison of the stability chart with the journal behaviors obtained from the nonlinear transient analysis. The results obtained from the perturbation analysis and the nonlinear transient analysis was in good agreement. These analysis shows that the effect of the centrifugal growth of the shaft on the threshold speed of whirl instability was significant in high rotational speed. By considering the effect, the proper herringbone-groove geometries for ultra high-speed operations were obtained in this paper.

Index Terms—Herringbone bearings, aerodynamic bearings, ultra high-speed rotations, stability analysis.

Norifumi Miyanaga is with Kanto-Gakuin University, 1-50-1 Mutsuura-Higashi, Kanazawa-Ku, Yokohama, Japan (e-mail: miyanaga@kanto-gakuin.ac.jp).
Jun Tomioka is with Waseda University, 3-4-1 Okubo, Shinjuku-Ku, Tokyo, Japan (e-mail: tomioka@waseda.jp).

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Cite: Norifumi Miyanaga and Jun Tomioka, "Stability Analysis of Herringbone-Grooved Aerodynamic Journal Bearings for Ultra High-Speed Rotations," International Journal of Materials, Mechanics and Manufacturing vol. 4, no. 3, pp. 156-161, 2016.

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