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International Journal of Rotating Machinery
Volume 2007, Article ID 90631, 8 pages
http://dx.doi.org/10.1155/2007/90631
Research Article

Analysis of Rotor-to-Stator Rub in a Large Steam Turbogenerator

Dipartimento di Meccanica, Politecnico di Milano, Milan 20156, Italy

Received 6 June 2006; Accepted 19 December 2006

Academic Editor: K. Kawaike

Copyright © 2007 Paolo Pennacchi and Andrea Vania. 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

Rotor-to-stator rub is a very common topic in rotor dynamics and several models have been proposed in the literature. Anyhow these models are often able to explain only the experimental dynamical behaviour of simple test rigs, which are deliberately reproducing a Jeffcott rotor. On the contrary case, histories related to real machines are seldom presented and analysed. The aim of this paper is to present an actual case history of a large turbogenerator unit that was subjected to partial arc rubs. The experimental results are shown and discussed along with the model-based diagnostic strategy employed to identify the fault severity and the location of the shaft cross-sections where the heaviest rubs occurred. Comparisons between experimental data and simulated vibrations caused by the identified fault are shown to validate the proposed methodology.