Author:
Chen Changmin,Jing Jianping,Cong Jiqing
Abstract
Purpose
The infinitesimal perturbation (IP) method is commonly used in calculating stiffness and damping of journal bearing in horizon rotor systems. The boundary condition (BC) for the perturbed pressure is assumed being zero at leading edge of film, although it is usually not zero because of nonzero pressure gradient. This assumption is sufficiently accurate for most purpose in horizon rotors. However, for journal bearing in vertical rotor-bearing systems, the BC with the assumption in IP method will bring in significant errors in calculating linear dynamic coefficients. This paper aims to propose a method to obtain the dynamic coefficients of journal bearing in vertical rotors.
Design/methodology/approach
The stiffness and damping are approached based on IP method and the modified BC of perturbed pressure. As it is difficult to predict perturbed pressure at leading edge at a fixed coordinate system using IP method, a dynamic coordinate system is introduced in this method, of which the origin on circumferential direction is defined as the leading edge of film.
Findings
The effectiveness and accuracy of proposed IP method in dynamic coordinate (IPMDC) system are verified by comparing the obtained results with analytical solutions. The comparison shows that the results from IPMDC present a good agreement with the analytic solutions.
Originality/value
The proposed method can be applied in obtaining linear dynamic coefficients of journal bearing in vertical rotors with high precisions. Instead of the usual nonlinear analysis of vertical rotors, this method provides a feasibility of predicting the instability threshold of vertical rotor-bearing systems via linear models.
Subject
Surfaces, Coatings and Films,General Energy,Mechanical Engineering
Reference19 articles.
1. Experimental analysis of tilting pad journal bearing influence in a vertical rotating system,1988
2. Nonlinear dynamic behaviour of vertical and horizontal rotors in compliant liner tilting pad journal bearings: some design considerations;Tribology International,2015
3. Whirl and whip instabilities in rotor-bearing system considering a nonlinear force model;Journal of Sound and Vibration,2008
4. Calculation of journal bearing dynamic characteristics including journal misalignment and bearing structural deformation©;Tribology Transactions,2004
5. Stability and transient motion of a vertical three-lobe bearing system;Journal of Engineering for Industry,2010
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