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Main Title: Weakly nonlinear analysis of thermoacoustic instabilities in annular combustors
Author(s): Ghirardo, G.
Juniper, M. P.
Moeck, Jonas P.
Type: Article
Language Code: en
Abstract: Rotationally symmetric annular combustors are of practical importance because they generically resemble combustion chambers in gas turbines, in which thermoacoustically driven oscillations are a major concern. We focus on azimuthal thermoacoustic oscillations and model the fluctuating heat release rate as being dependent only on the local pressure in the combustion chamber. We study the dynamics of the annular combustor with a finite number of compact flames equispaced around the annulus, and characterize the flames’ response with a describing function. We discuss the existence, amplitude and the stability of standing and spinning waves, as a function of: (i) the number of the burners; (ii) the acoustic damping in the chamber; (iii) the flame response. We present the implications for industrial applications and the future direction of investigations. We then present as an example the first theoretical study of thermoacoustic triggering in annular combustors, which shows that rotationally symmetric annular chambers that are thermoacoustically unstable do not experience only stable spinning solutions, but can also experience stable standing solutions. We finally test the theory on one experiment with good agreement.
Issue Date: 2016
Date Available: 27-Oct-2017
DDC Class: 530 Physik
Subject(s): acoustics
low-dimensional models
nonlinear dynamical systems
Journal Title: Journal of fluid mechanics
Publisher: Cambridge University Press
Publisher Place: Cambridge
Volume: 805
Publisher DOI: 10.1017/jfm.2016.494
Page Start: 52
Page End: 87
EISSN: 1469-7645
ISSN: 0022-1120
Notes: Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.
Appears in Collections:FG Experimentelle Strömungsmechanik » Publications

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