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Advances in Acoustics and Vibration
Volume 2016, Article ID 7368787, 17 pages
http://dx.doi.org/10.1155/2016/7368787
Research Article

Kaybob Revisited: What We Have Learned about Compressor Stability from Self-Excited Whirling

1RODYN Vibration Analysis, Inc., Charlottesville, VA, USA
2Rotor Dynamics Laboratory, Mechanical and Aerospace Engineering Department, University of Virginia, Charlottesville, VA, USA
3Rotating Machinery and Controls Laboratory, Mechanical and Aerospace Engineering Department, University of Virginia, Charlottesville, VA, USA

Received 11 July 2016; Accepted 14 November 2016

Academic Editor: Lars Hakansson

Copyright © 2016 Edgar J. Gunter and Brian K. Weaver. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The Kaybob compressor failure of 1971 was an excellent historic example of rotordynamic instability and the design factors that affect this phenomenon. In the case of Kaybob, the use of poorly designed bearings produced unstable whirling in both the low and high pressure compressors. This required over five months of vibration troubleshooting and redesign along with over 100 million modern U.S. dollars in total costs and lost revenue. In this paper, the history of the Kaybob compressor failure is discussed in detail including a discussion of the ineffective bearing designs that were considered. Modern bearing and rotordynamic analysis tools are then employed to study both designs that were considered along with new designs for the bearings that could have ultimately restored stability to the machine. These designs include four-pad, load-between-pad bearings and squeeze film dampers with a central groove. Simple relationships based on the physics of the system are also used to show how the bearings could be tuned to produce optimum bearing stiffness and damping of the rotor vibration, producing insights which can inform the designers as they perform more comprehensive analyses of these systems.