Large-Eddy Simulation of combustion instabilities in a variable-length combustor

Garby, Romain; Selle, Laurent; Poinsot, Thiérry

doi:10.1016/j.crme.2012.10.020

Cited by 97 publications

(60 citation statements)

References 33 publications

(37 reference statements)

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“…They note that the chemistry is not fast enough to anchor the flame at the injection point and the flame is instead anchored at the dump plane by the hot burnt gases in the recirculation region. 21 Guézennec et al showed that in an unstable 4.75 in case the triple flame forms at the backstep and is extinguished when it hits the wall, the time of this movement is linked to the first longitudinal mode. 22 Results in this work find that the mechanism at play in the unstable case is more complex and dynamic.…”

Section: B Baroclinic Torquementioning

confidence: 98%

“…The existence of a triple flame structure in the combustor was also suggested as a key element in the instability mechanism. 21 Guézennec et al provided results of an unstable 4.75 in configuration showing the movement of a triple point occurred at the same frequency as the the first longitudinal mode. 22 To date no simulations of stable operating conditions have been published in the literature.…”

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confidence: 93%

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Combustion Instability Mechanisms in a Pressure-coupled Gas-gas Coaxial Rocket Injector

Harvazinski

Huang

Sankaran

et al. 2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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An investigation of the instability mechanism present in a laboratory rocket combustor is performed using computational fluid dynamics (CFD) simulations. Three cases are considered which show different levels of instability experimentally. Computations reveal three main aspects to the instability mechanism, the timing of the pressure pulses, increased mixing due to the baroclinic torque, and the presence of unsteady tribrachial flame. The stable configuration shows that fuel is able to flow into the combustor continuously allowing continuous heat release. The unstable configuration shows that a disruption in the fuel flow into the combustor allows the heat release to move downstream and new fuel to accumulate in the combustor without immediately burning. Once the large amounts of fuel in the combustor burn there is rapid rise in pressure which coincides with the timing of the acoustic wave in the combustor. The two unstable cases show different levels of instability and different reignition mechanisms.

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Section: B Baroclinic Torquementioning

confidence: 98%

mentioning

confidence: 93%

Combustion Instability Mechanisms in a Pressure-coupled Gas-gas Coaxial Rocket Injector

Harvazinski

Huang

Sankaran

et al. 2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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“…As a consequence, the eigenmodes of the chamber can change and their stability too. Adiabatic and non-adiabatic con gurations exhibit different stability regions: this is easily observed in simulations where changing the wall heat transfer condition from adiabatic to isothermal is suf cient to trigger or damp modes [106,107] . This is a rather obvious effect due to changes in sound speeds and ame shapes which will not be discussed here.…”

Section: The Effects Of Wall Temperaturesmentioning

confidence: 99%

Prediction and control of combustion instabilities in real engines

Poinsot

2017

Proceedings of the Combustion Institute

551

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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“…Differences in frequency or amplitude may occur when the temperature field and the FTF in the simulation only partially match those in the experiment, but the simulation can usually be used for further investigation of the thermoacoustic mode. There are numerous studies of combustion instabilities that illustrate that LES with adiabatic walls can show a reasonable agreement with experiments: the study on a lean-premixed swirl combustor by Huang et al [8] , the LES-studies on the PRECCIN-STA configuration [9][10][11] , the massively parallel LES of a realistic helicopter combustion chamber by Wolf et al [12] , LESs of model rocket combustors (Garby et al [13] , Urbano et al [14] ) or the LESstudies of bluff-body stabilized flames by Li et al [15] and Ghani et al [16] .…”

Section: Introductionmentioning

confidence: 99%

“…• Type 1: Adiabatic walls: the majority of recent LESs simply consider the walls to be adiabatic [8][9][10][11][12][13][14][15][16][19][20][21][22] .…”

Section: Introductionmentioning

confidence: 99%

Coupling heat transfer and large eddy simulation for combustion instability prediction in a swirl burner

Kraus

Selle

Poinsot

2018

Combustion and Flame

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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. Large eddy simulations (LES) of combustion instabilities are often performed with simplified thermal wall boundary conditions, typically adiabatic walls. However, wall temperatures directly affect the gas temperatures and therefore the sound speed field. They also control the flame itself, its stabilization characteristics and its response to acoustic waves, changing the flame transfer functions (FTFs) of many combustion chambers. This paper presents an example of LES of turbulent flames fully coupled to a heat conduction solver providing the temperature in the combustor walls. LES results obtained with the fully coupled approach are compared to experimental data and to LES performed with adiabatic walls for a swirled turbulent methane/air burner installed at Engler-Bunte-Institute, Karlsruhe Institute of Technology and German Aerospace Center (DLR) in Stuttgart. Results show that the fully coupled approach provides reasonable wall temperature estimations and that heat conduction in the combustor walls strongly affects both the mean state and the unstable modes of the combustor. The unstable thermoacoustic mode observed experimentally at 750 Hz is captured accurately by the coupled simulation but not by the adiabatic one, suggesting that coupling LES with heat conduction solvers within combustor walls may be necessary in other configurations in order to capture flame dynamics.

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Large-Eddy Simulation of combustion instabilities in a variable-length combustor

Cited by 97 publications

References 33 publications

Combustion Instability Mechanisms in a Pressure-coupled Gas-gas Coaxial Rocket Injector

Combustion Instability Mechanisms in a Pressure-coupled Gas-gas Coaxial Rocket Injector

Prediction and control of combustion instabilities in real engines

Coupling heat transfer and large eddy simulation for combustion instability prediction in a swirl burner

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