Modeling of Tilting-Pad Journal Bearings with Transfer Functions

Tilting-pad journal bearings are widely used to promote stability in modern rotating machinery. However, the dynamics associated with pad motion alters this stabilizing capacity depending on the operating speed of the machine and the bearing geometric parameters, particularly the bearing preload. In...

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Main Authors: J. A. Vázquez, L. E. Barrett
Format: Article
Language:English
Published: Wiley 2001-01-01
Series:International Journal of Rotating Machinery
Subjects:
Online Access:http://dx.doi.org/10.1155/S1023621X0100001X
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author J. A. Vázquez
L. E. Barrett
author_facet J. A. Vázquez
L. E. Barrett
author_sort J. A. Vázquez
collection DOAJ
description Tilting-pad journal bearings are widely used to promote stability in modern rotating machinery. However, the dynamics associated with pad motion alters this stabilizing capacity depending on the operating speed of the machine and the bearing geometric parameters, particularly the bearing preload. In modeling the dynamics of the entire rotor-bearing system, the rotor is augmented with a model of the bearings. This model may explicitly include the pad degrees of freedom or may implicitly include them by using dynamic matrix reduction methods. The dynamic reduction models may be represented as a set of polynomials in the eigenvalues of the system used to determine stability. All tilting-pad bearings can then be represented by a fixed size matrix with polynomial elements interacting with the rotor. This paper presents a procedure to calculate the coefficients of polynomials for implicit bearing models. The order of the polynomials changes to reflect the number of pads in the bearings. This results in a very compact and computationally efficient method for fully including the dynamics of tilting-pad bearings or other multiple degrees of freedom components that interact with rotors. The fixed size of the dynamic reduction matrices permits the method to be easily incorporated into rotor dynamic stability codes. A recursive algorithm is developed and presented for calculating the coefficients of the polynomials. The method is applied to stability calculations for a model of a typical industrial compressor.
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spelling doaj-art-814caab5d9ad4cb0ad5ab76cb43bb78b2025-08-20T03:35:06ZengWileyInternational Journal of Rotating Machinery1023-621X2001-01-017111010.1155/S1023621X0100001XModeling of Tilting-Pad Journal Bearings with Transfer FunctionsJ. A. Vázquez0L. E. Barrett1Department of Mechanical and Aerospace Engineering, School of Engineering and Applied Science, University of Virginia, Charlottesville 22903, VA, USADepartment of Mechanical and Aerospace Engineering, School of Engineering and Applied Science, University of Virginia, Charlottesville 22903, VA, USATilting-pad journal bearings are widely used to promote stability in modern rotating machinery. However, the dynamics associated with pad motion alters this stabilizing capacity depending on the operating speed of the machine and the bearing geometric parameters, particularly the bearing preload. In modeling the dynamics of the entire rotor-bearing system, the rotor is augmented with a model of the bearings. This model may explicitly include the pad degrees of freedom or may implicitly include them by using dynamic matrix reduction methods. The dynamic reduction models may be represented as a set of polynomials in the eigenvalues of the system used to determine stability. All tilting-pad bearings can then be represented by a fixed size matrix with polynomial elements interacting with the rotor. This paper presents a procedure to calculate the coefficients of polynomials for implicit bearing models. The order of the polynomials changes to reflect the number of pads in the bearings. This results in a very compact and computationally efficient method for fully including the dynamics of tilting-pad bearings or other multiple degrees of freedom components that interact with rotors. The fixed size of the dynamic reduction matrices permits the method to be easily incorporated into rotor dynamic stability codes. A recursive algorithm is developed and presented for calculating the coefficients of the polynomials. The method is applied to stability calculations for a model of a typical industrial compressor.http://dx.doi.org/10.1155/S1023621X0100001XRotating machine dynamicsTilting-pad bearingsDynamic reductionStability calculationsTransfer functions.
spellingShingle J. A. Vázquez
L. E. Barrett
Modeling of Tilting-Pad Journal Bearings with Transfer Functions
International Journal of Rotating Machinery
Rotating machine dynamics
Tilting-pad bearings
Dynamic reduction
Stability calculations
Transfer functions.
title Modeling of Tilting-Pad Journal Bearings with Transfer Functions
title_full Modeling of Tilting-Pad Journal Bearings with Transfer Functions
title_fullStr Modeling of Tilting-Pad Journal Bearings with Transfer Functions
title_full_unstemmed Modeling of Tilting-Pad Journal Bearings with Transfer Functions
title_short Modeling of Tilting-Pad Journal Bearings with Transfer Functions
title_sort modeling of tilting pad journal bearings with transfer functions
topic Rotating machine dynamics
Tilting-pad bearings
Dynamic reduction
Stability calculations
Transfer functions.
url http://dx.doi.org/10.1155/S1023621X0100001X
work_keys_str_mv AT javazquez modelingoftiltingpadjournalbearingswithtransferfunctions
AT lebarrett modelingoftiltingpadjournalbearingswithtransferfunctions