The influence of oil-film turbulence on the parametric excitation instability of a symmetrical unbalanced rotor in short bearings is analysed for different values of Reynolds number. The method of calculating the journal orbit is described together with the method for predicting the synchronous orbit whose stability is to be evaluated.
In addition to examples of calculated and predicted orbits, stability maps are given for dimensionless unbalance values equal to 0.2, 0.3 and 0.4 and for the Reynolds numbers of 2500, 5000 and 10000.
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References
1.
LundJ. W.NielsenH. B.Instability threshold of an unbalanced, rigid rotor in short journal bearings. IMechE Conference on Vibrations in rotating machinery, Cambridge, 1980, pp. 91–95.
2.
HashimotoH.WadaS.An influence of inertia forces on stability of turbulent journal bearings. Bull. J. Soc. Mech. Engrs, 1982, 25(202), 653–662.
3.
CaponeG.RussoM.RussoR.Dynamic characteristics and stability of a journal bearing in a non laminar lubrication regime. Tribol. Int., 1987, 20(5), 255–260.
4.
HashimotoH.WadaS.ItoJ. I.An application of short bearing theory to dynamic characteristics problems of turbulent journal bearings. Trans. ASME, J. Tribol., 1987, 109(2), 307–314.
5.
CaponeG.RussoM.RussoR.Inertia and turbulence effects on dynamic characteristics and stability of rotor bearings systems. Trans. ASME, J. Tribol., 1991, 113(1), 58–64.
6.
DuboisG. B.OcvirckF. W.Analytical derivation and experimental evaluation of short-bearing approximation for full journal bearings. NACA report 1157, 1953.
7.
ConstantinescuV. N.Slidings bearings, 1985 (Allerton Press, New York).
8.
CaponeG.RussoM.RussoR.Un modello semplificato per l'analisi dei cuscinetti cilindrici in regime di lubrificazione non laminare. Tribologia e Lubrificazione, 1986, 2, 59–64.
9.
CaponeG.RussoM.Short bearing theory prediction of inertial turbulent journal orbits. Trans. ASME, J. Tribol., 1990, 112(4), 643–649.
10.
McLachlanN. W.Theory and application of Mathieu functions, 1964 (Dover Publications, New York).
11.
DianaG.CheliF.ManentiA.PetroneF.Non linear effects in lubricated bearings. Vibration and wear in high speed rotating machinery. NATO ASI Ser., Ser. E.: Appl. Sci., 1990, 174.
12.
LundJ. W.Self-excited stationary whirl orbits of a journal in a sleeve bearing. PhD thesis, Rensselaer Polytechnic Institute, New York, 1966.
