DNS of Intrinsic ThermoAcoustic modes in laminar premixed flames

Courtine, Emilien; Selle, Laurent; Poinsot, Thiérry

doi:10.1016/j.combustflame.2015.07.002

Cited by 76 publications

(71 citation statements)

References 38 publications

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“…All mechanisms take place between the dump plane and the extreme position of the ame: downstream convection of the vortical wave created by mode conversion at the dump plane followed by a fast acoustic propagation leading to a new mode conversion. No acoustic reection from the chamber inlet or outlet is involved: this was also veri ed by Courtine [58] by performing the same simulation in a chamber where the lengths of inlet and combustion chamber were multiplied by two, leading to exactly the same mode.…”

Section: Intrinsic Acoustic Modesmentioning

confidence: 88%

“…Still, the ame oscillate. This point has been discussed in the literature and is still an open question [58,119,120] .…”

Section: Intrinsic Acoustic Modesmentioning

confidence: 99%

“…Most studies on ITA modes have been theoretical [119] or numerical [58] but up to now, experimental work has been limited to the PhD work of Hoeijmakers in Eindhoven. To construct a setup exhibiting an ITA mode, the dif culty is that inlet and outlet must both be as anechoic as possible to ensure that R 1 = R 2 = 0 .…”

Section: Intrinsic Acoustic Modesmentioning

confidence: 99%

“…A simple pedagogical model for combustion instabilities: a laminar ame stabilized at the dump plane separating the injection duct and the combustion chamber. The color eld is the velocity modulus [58] .…”

Section: A Model Problem Illustrating Key Features Of Combustion Instmentioning

confidence: 99%

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Prediction and control of combustion instabilities in real engines

Poinsot

2017

Proceedings of the Combustion Institute

562

216

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This is an author-deposited version published in: http://oatao.univ-toulouse.fr/ Eprints ID: 17713Open Archive Toulouse Archive Ouverte (OATAO) OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. To cite this version: AbstractThis paper presents recent progress in the eld of thermoacoustic combustion instabilities in propulsion engines such as rockets or gas turbines. Combustion instabilities have been studied for more than a century in simple laminar con gurations as well as in laboratory-scale turbulent ames. These instabilities are also encountered in real engines but new mechanisms appear in these systems because of obvious differences with academic burners: larger Reynolds numbers, higher pressures and power densities, multiple inlet systems, complex fuels. Other differences are more subtle: real engines often feature speci c unstable modes such as azimuthal instabilities in gas turbines or transverse modes in rocket chambers. Hydrodynamic instability modes can also differ as well as the combustion regimes, which can require very different simulation models. The integration of chambers in real engines implies that compressor and turbine impedances control instabilities directly so that the determination of the impedances of turbomachinery elements becomes a key issue. Gathering experimental data on combustion instabilities is dif cult in real engines and large Eddy simulation (LES) has become a major tool in this eld. Recent examples, however, show that LES is not suf cient and that theory, even in these complex systems, plays a major role to understand both experimental and LES results and to identify mitigation techniques.

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Section: Intrinsic Acoustic Modesmentioning

confidence: 88%

“…Still, the ame oscillate. This point has been discussed in the literature and is still an open question [58,119,120] .…”

Section: Intrinsic Acoustic Modesmentioning

confidence: 99%

Section: Intrinsic Acoustic Modesmentioning

confidence: 99%

Section: A Model Problem Illustrating Key Features Of Combustion Instmentioning

confidence: 99%

See 2 more Smart Citations

Prediction and control of combustion instabilities in real engines

Poinsot

2017

Proceedings of the Combustion Institute

562

216

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“…For example, recent studies show the existence of flame-intrinsic instabilities [9][10][11]. Their impact on and contribution to the development of unstable modes in combustors, especially in real engines with complex geometries, is difficult to assess.…”

Section: Introductionmentioning

confidence: 99%

Influence of Heat Transfer and Material Temperature on Combustion Instabilities in a Swirl Burner

Kraus

Selle

Poinsot

et al. 2016

Journal of Engineering for Gas Turbines and Power

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OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in : http://oatao.univ-toulouse.fr/ Eprints ID : 17948 The current work focuses on the large eddy simulation (LES) of combustion instability in a laboratory-scale swirl burner. Air and fuel are injected at ambient conditions. Heat conduction from the combustion chamber to the plenums results in a preheating of the air and fuel flows above ambient conditions. The paper compares two computations: In the first computation, the temperature of the injected reactants is 300 K (equivalent to the experiment) and the combustor walls are treated as adiabatic. The frequency of the unstable mode (% 635 Hz) deviates significantly from the measured frequency (% 750 Hz).In the second computation, the preheating effect observed in the experiment and the heat losses at the combustion chamber walls are taken into account. The frequency (% 725 Hz) of the unstable mode agrees well with the experiment. These results illustrate the importance of accounting for heat transfer/losses when applying LES for the prediction of combustion instabilities. Uncertainties caused by unsuitable modeling strategies when using computational fluid dynamics for the prediction of combustion instabilities can lead to an improper design of passive control methods (such as Helmholtz resonators) as these are often only effective in a limited frequency range.

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