Alessandra Bigongiari
A Green's function approach to predict nonlinear thermoacoustic instabilities in combustors
Bigongiari, Alessandra; Heckl, Maria A.
Abstract
The prediction of thermoacoustic instabilities is fundamental for combustion systems such as domestic burners and industrial gas turbine engines. High-amplitude pressure oscillations cause thermal and mechanical stress to the equipment, leading to premature wear or even critical damage. In this paper we present a new approach to produce nonlinear (i.e. amplitude-dependent) stability maps of a combustion system as a function of various parameters. Our approach is based on the tailored Green’s function of the combustion system, which we calculate analytically. To this end, we assume that the combustor is one-dimensional, and we describe its boundary conditions through reflection coefficients. The heat release is modelled by a generalised law. This includes a direct-feedback term in addition to the usual time-lag term; moreover, its parameters (time lag, coupling coefficients) depend on the oscillation amplitude. The model provides new insight into the physical mechanism of the feedback between heat release rate and acoustic perturbations. It predicts the key nonlinear features of the thermoacoustic feedback, such as limit cycles, bistability and hysteresis. It also explains the frequency shift in the acoustic modes.
Citation
Bigongiari, A., & Heckl, M. A. (2016). A Green's function approach to predict nonlinear thermoacoustic instabilities in combustors. Journal of Fluid Mechanics, 970 - 996. https://doi.org/10.1017/jfm.2016.332
Journal Article Type | Article |
---|---|
Acceptance Date | May 10, 2016 |
Publication Date | Jun 15, 2016 |
Journal | Journal of Fluid Mechanics |
Print ISSN | 0022-1120 |
Publisher | Cambridge University Press |
Peer Reviewed | Peer Reviewed |
Pages | 970 - 996 |
DOI | https://doi.org/10.1017/jfm.2016.332 |
Keywords | acoustics; combustion; nonlinear instability |
Publisher URL | https://doi.org/10.1017/jfm.2016.332 |
Files
heckl_2016.pdf
(2.2 Mb)
PDF
Publisher Licence URL
https://creativecommons.org/licenses/by/4.0/
You might also like
Editorial for the special JSV issue in memory of Shôn Ffowcs Williams
(2023)
Journal Article
A unified framework for acoustic instabilities based on the tailored Green's function
(2022)
Journal Article
3-D thermoacoustic instability analysis based on Green's function approach
(2022)
Journal Article
Analytical approximations for heat release rate laws in the time- and frequency-domains
(2020)
Journal Article
Advances by the Marie Curie project TANGO in thermoacoustics
(2019)
Journal Article
Downloadable Citations
About Keele Repository
Administrator e-mail: research.openaccess@keele.ac.uk
This application uses the following open-source libraries:
SheetJS Community Edition
Apache License Version 2.0 (http://www.apache.org/licenses/)
PDF.js
Apache License Version 2.0 (http://www.apache.org/licenses/)
Font Awesome
SIL OFL 1.1 (http://scripts.sil.org/OFL)
MIT License (http://opensource.org/licenses/mit-license.html)
CC BY 3.0 ( http://creativecommons.org/licenses/by/3.0/)
Powered by Worktribe © 2024
Advanced Search