0
Research Papers: Gas Turbines: Structures and Dynamics

The Effect of Tilting Pad Journal Bearing Dynamic Models on the Linear Stability Analysis of an 8-Stage Compressor

[+] Author and Article Information
Timothy W. Dimond1

Rotating Machinery and Controls Laboratory, Department of Mechanical and Aerospace Engineering,  University of Virginia, Charlottesville, VA 22904-4746twd5c@virginia.edu

Amir A. Younan, Paul Allaire

Rotating Machinery and Controls Laboratory, Department of Mechanical and Aerospace Engineering,  University of Virginia, Charlottesville, VA 22904-4746

1

Corresponding author.

J. Eng. Gas Turbines Power 134(5), 052503 (Feb 23, 2012) (7 pages) doi:10.1115/1.4005208 History: Received September 12, 2010; Revised September 22, 2011; Published February 23, 2012; Online February 23, 2012

Rotordynamic instability, a self-excited vibration phenomenon, can lead to equipment failures, reduced production rates, and expensive redesign. Properly characterizing the stability response of flexible rotors on tilting pad bearings is therefore vital. Typically, this must be first considered during the design stage with computer modeling. Previous studies have demonstrated that non-synchronous bearing coefficients give a lower estimate of bearing stability than the eight synchronously reduced tiling pad bearing coefficients. However, a study of a reduced order non-synchronous stiffness-damping-mass (KCM) model and the effect on stability estimates has not been done previously for the same rotor model. In this paper, four load-between-pad tilting pad bearing designs, two four-pad and two five-pad, are considered. The stability margin for an eight-stage gas reinjection compressor is estimated for the four bearings, using a full KC representation, the KCM representation, and synchronously reduced bearing coefficients. The full KC representation gave the lowest estimate of stability margin, with up to 18% difference between full KC and KCM and up to 109% difference between full KC and synchronously reduced bearing coefficients. The results indicate that the KCM bearing representation does not necessarily result in the lowest estimate of rotordynamic stability margin, which is of significant interest to rotating machinery designers.

FIGURES IN THIS ARTICLE
<>
Copyright © 2012 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Eight stage gas reinjection compressor [26]

Grahic Jump Location
Figure 2

Eight stage compressor finite element model

Grahic Jump Location
Figure 3

Bearing Design 1 horizontal complex impedance - four pads, 50% pivot offset

Grahic Jump Location
Figure 4

Bearing Design 2 complex impedance - four pads, 55% pivot offset

Grahic Jump Location
Figure 5

Bearing Design 3 complex impedance - five pads, 50% pivot offset

Grahic Jump Location
Figure 6

Bearing Design 4 complex impedance - five pads, 55% pivot offset

Grahic Jump Location
Figure 7

Bearing Design 1 stability margin - four pads, 50% pivot offset

Grahic Jump Location
Figure 8

Bearing Design 2 stability margin - four pads, 55% pivot offset

Grahic Jump Location
Figure 9

Bearing Design 3 stability margin - five pads, 50% pivot offset

Grahic Jump Location
Figure 10

Bearing Design 4 stability margin - five pads, 55% pivot offset

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In