Negative stiffness in gas turbine leaf seals

Jahn, Ingo H. J., Franceschini, Gervas, Owen, Andrew K. and Gillespie, David R. H. (2011). Negative stiffness in gas turbine leaf seals. In: Proceedings of ASME Turbo Expo 2011. ASME Turbo Expo (ASME TE, 2011), Vancouver, BC, Canada, (993-998). 6-10 June 2011. doi:10.1115/GT2011-46483

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Author Jahn, Ingo H. J.
Franceschini, Gervas
Owen, Andrew K.
Gillespie, David R. H.
Title of paper Negative stiffness in gas turbine leaf seals
Conference name ASME Turbo Expo (ASME TE, 2011)
Conference location Vancouver, BC, Canada
Conference dates 6-10 June 2011
Proceedings title Proceedings of ASME Turbo Expo 2011
Place of Publication New York, United States
Publisher ASME Digital Library
Publication Year 2011
Sub-type Fully published paper
DOI 10.1115/GT2011-46483
ISBN 9780791854655
Volume Volume 5: Heat Transfer, Parts A and B
Start page 993
End page 998
Total pages 6
Collection year 2012
Language eng
Abstract/Summary The stiffness of contacting shaft seals such as brush seals and leaf seals is a required characteristic to accurately predict their performance and life in the gas turbine engine. This paper describes the results of a test campaign in which a series of eccentric rotor excursions are applied at low rotational speed and engine representative pressure differences to characterise the behaviour of a prototype leaf seal. A phenomenon that may best be described as negative seal stiffness is reported. Here, the displacement of the seal rotor to an eccentric position causes a resultant force, which, rather than trying to return the rotor to a central position, acts to amplify its displacement. These data were used to develop an empirical model of the seal behaviour. It was possible to model the negative stiffness phenomenon and show that it is caused by a combination of two effects: the inherent mechanical stiffness of the leaf pack, and the aerodynamic stiffness of the seal. The latter is caused by the pressure distribution and changes in the flow field through the leaf pack as a result of the displacement of the rotor.
Q-Index Code E1
Q-Index Status Confirmed Code
Institutional Status Non-UQ
Additional Notes Presented during the Paper Session "Heat Transfer: Internal Air and Seals (with Turbomachinery). Compliant Seals." Published as ASME Paper GT2011-4Paper no. GT2011-464836483.

Document type: Conference Paper
Collections: School of Mechanical & Mining Engineering Publications
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Created: Fri, 20 Apr 2012, 14:47:04 EST by Ingo Jahn on behalf of School of Mechanical and Mining Engineering