Imperfect symmetry of real annular combustors: beating thermoacoustic modes and heteroclinic orbits
OPEN ACCESS
Loading...
Author / Producer
Date
2021-10-25
Publication Type
Journal Article
ETH Bibliography
yes
Citations
Altmetric
OPEN ACCESS
Data
Rights / License
Abstract
In jet engines and gas turbines, the annular shape of the combustion chamber allows the appearance of self-oscillating azimuthal thermoacoustic modes. We report experimental evidence of a new type of modal dynamics characterised by periodic switching of the spinning direction and develop a theoretical model that fully reproduces this phenomenon and explains the underlying mechanisms. It is shown that tiny asymmetries of the geometry, the mean temperature field, the thermoacoustic response of the flames or the acoustic impedance of the walls, present in any real systems, can induce these heteroclinic orbits. The model also explains experimental observations showing a statistically dominant spinning direction despite the absence of swirling flow, or pairs of preferred nodal line directions.
Permanent link
Publication status
published
External links
Editor
Book title
Journal / series
Volume
925
Pages / Article No.
Publisher
Cambridge University Press
Event
Edition / version
Methods
Software
Geographic location
Date collected
Date created
Subject
combustion; acoustics; nonlinear dynamical systems
Organisational unit
09471 - Noiray, Nicolas / Noiray, Nicolas
Notes
Funding
765998 - Annular Instabilities and Transient Phenomena in Gas Turbine Combustors (EC)