Effect of possible rotor deformation on the probability of face contact for a liquid film bearing.pdfVIP

Tribology International 109 (2017) 297–310 Contents lists available at ScienceDirect Tribology International journal homepage: /locate/triboint E?ect of possible rotor deformation on the probability of face contact for a liquid ?lm bearing N.Y. Baileya,b, S. Hibberdb, H. Powerc,? a Department of Mechanical Engineering, University of Bath, Bath, BA2 7AY, UK b Mathematical Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK c Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK MARK ARTICLE INFO Keywords: Reynolds equation Method of derived distribution Probability density function Face contact ABSTRACT The possibility of face contact is examined for a coaxial rotor-stator bearing in dynamic motion constrained by a highly rotating very thin liquid ?lm. A modi?ed Reynolds equation for pressurised ?ow is coupled to the bearing structure leading to determination of the bearing gap from solving a nonlinear second-order non-autonomous ordinary di?erential equation. Periodic solutions are found via a mapping solver. Rotor deformation is parametrised by a coning angle and considered a random variable. The method of derived distributions is used to quantify variation in coning angle and examine the probability of rotor-stator contact. Additionally, e?ects of possible destabilising random aspects on the axial rotor oscillations are investigated. Exact solutions for probability of contact are obtained for various bearing con?gurations. 1. Introduction Liquid ?lm bearings typically comprise a coaxial axisymmetric rotor and stator pair with a thin liquid ?lm used to maintain a clearance between the faces when the bearing experiences external loading. The local ?lm pressure may be enhanced through normal motion of the plates and ?ow dynamics associated with the bearings rotational motion. Commonly industrial applications of this type of bearing are required to operate with increasing rotor speed; correspondingly inertia