Stability and Hopf bifurcations in rotor-bearing-foundation systems of turbines and generators

The paper investigates the type of Hopf bifurcations existing in slender rotor systems of turbines and generators with respect to the design of bearings, foundations, and rotors. Two bearing profiles applied mostly in such rotor systems, the lemon bore and the partial arc bearing are considered in t...

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Bibliographic Details
Published in:Tribology international 2020-05, Vol.145, p.106154, Article 106154
Main Author: Chasalevris, Athanasios
Format: Article
Language:English
Subjects:
Bearing design
Bearings
Bifurcations
Design standards
Generators
Hopf bifurcation
Lemons
Limit cycles
Nonlinear analysis
Nonlinear stability
Rotors
Stability analysis
Turbines
Turbomachinery
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Summary:The paper investigates the type of Hopf bifurcations existing in slender rotor systems of turbines and generators with respect to the design of bearings, foundations, and rotors. Two bearing profiles applied mostly in such rotor systems, the lemon bore and the partial arc bearing are considered in the analysis with nonlinear impedance. Simplistic models of single degree of freedom per direction are considered for the bearing pedestals. Part of the paper investigates the bifurcation type in simple Jeffcott rotor mounted on nonlinear lemon bore and partial arc bearings with resilient pedestals, aiming to raise design concerns which influence the type of bifurcation. The results highlight the need for nonlinear stability assessment in the standard design of turbines and generators. •The high sensitivity of the Bifurcation type in rotor systems in bearing profile.•Nonlinear stability assessment of complete turbine-generator models.•Design rules for the prediction of bifurcation type in turbines and generators.•Sensitivity of the whirling frequency ratio at limit cycle to the design parameters.•Higher pedestal mass and damping provide supercritical bifurcations.
ISSN:0301-679X
1879-2464
DOI:10.1016/j.triboint.2019.106154