Wall-temperature effects on flame response to acoustic oscillations

Mejía, Daniel; Selle, Laurent; Bazile, R.; Poinsot, Thiérry

doi:10.1016/j.proci.2014.07.015

Cited by 59 publications

(54 citation statements)

References 77 publications

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“…The second aspect of the ITA theory that may explain discrepancies is the computation of the FTF gain. Even though FTF measurements have been performed with upstream and downstream acoustic excitation, giving very consistent results and proving the velocity sensitive assumption [8], the FTF gain is sensitive to the location of the reference point used for velocity measurements [33,34]. Bringing the reference point closer to the dump plane would increase the FTF gain, thereby reducing the gap between theoretical predictions and DNS results.…”

Section: Stability Limitsmentioning

confidence: 93%

“…11. Although the study of non-linearities is not the purpose of this work, this frequency drop is likely to be due to an effective increase of the mean flame length as its feet are periodically pushed upstream by high amplitude acoustic waves passing through the rim [23,35]. This would result in an effective increase of the flame delayτ (the mean flow rate being fixed) and a subsequent drop of the instability frequencyf 1 ITA = 1/(2τ ).…”

Section: Stability Limitsmentioning

confidence: 99%

“…The DNS configuration corresponds to a laminar 2D dihedral flame previously studied in [23,24], on which a combustion chamber has been added for the study of intrinsic thermoacoustic modes (Fig. 1).…”

Section: Numerical Setupmentioning

confidence: 99%

“…First, the FTF was computed at very low confinement (S 2 /S 1 = 6) and compared to the experimental measurements performed by [23] on the same flame but in an unconfined configuration. For S 2 /S 1 = 6 (case REF-6.0 on no ITA mode is observed.…”

Section: Measurement Of the Ftf In An Intrinsically Unstable Systemmentioning

confidence: 99%

See 3 more Smart Citations

DNS of Intrinsic ThermoAcoustic modes in laminar premixed flames

Courtine

Selle

Poinsot

2015

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. , Emmert et al. 2015 suggest that thermoacoustic modes can appear in combustors with anechoic terminations, which have no acoustic eigenmodes. These modes, called here Intrinsic ThermoAcoustic (ITA), can be predicted with simple theoretical arguments, but have been ignored for a long time. They are reproduced in this paper using Direct Numerical Simulation (DNS) of a laminar premixed Bunsen type flame. DNS results and theory are compared showing very good agreement in terms of both frequency and mode structure. DNS confirms that the frequency of ITA modes does not depend on any acoustic characteristic of the burner. Based on a numerical evaluation of the Flame Transfer Function, stability limits of ITA modes predicted by theory are also recovered in the DNS with reasonable accuracy. Finally, DNS is used to analyze the mechanisms of ITA modes.

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Section: Stability Limitsmentioning

confidence: 93%

Section: Stability Limitsmentioning

confidence: 99%

Section: Numerical Setupmentioning

confidence: 99%

Section: Measurement Of the Ftf In An Intrinsically Unstable Systemmentioning

confidence: 99%

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DNS of Intrinsic ThermoAcoustic modes in laminar premixed flames

Courtine

Selle

Poinsot

2015

Combustion and Flame

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“…While cooling is obviously needed to preserve walls, its effects on the flames themselves has received less attention and is usually neglected in many CFD approaches. Flame/wall interaction, for example, is a field of combustion which has not been investigated yet with sufficient care [1][2][3][4][5][6] . In most cases, authors measure or compute the maximum wall heat fluxes induced by the flame but do not investigate the effects of the wall on the flame itself.…”

Section: Introductionmentioning

confidence: 99%

Joint experimental and numerical study of the influence of flame holder temperature on the stabilization of a laminar methane flame on a cylinder

Miguel-Brebion

Mejía

Xavier

et al. 2016

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. a b s t r a c tThe mechanisms controlling laminar flame anchoring on a cylindrical bluff-body are investigated using DNS and experiments. Two configurations are examined: water-cooled and uncooled steel cylinders. Comparisons between experimental measurements and DNS show good agreement for the flame root locations in the two configurations. In the cooled case, the flame holder is maintained at about 300 K and the flame is stabilized in the wake of the cylinder, in the recirculation zone formed by the products of combustion. In the uncooled case, the bluff-body reaches a steady temperature of about 700 K in both experiment and DNS and the flame is stabilized closer to it. The fully coupled DNS of the flame and the temperature field in the bluff-body also shows that capturing the correct radiative heat transfer from the bluff-body is a key ingredient to reproduce experimental results.

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Analysis of the sound sources of lean premixed methane–air flames

et al. 2021

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Two investigations on the sound generation mechanisms of lean methane–air flames are reviewed and linked. A two‐step approach is used for the analysis. First, the compressible conservation equations are solved in a large‐eddy simulation formulation to compute the acoustic source terms of the reacting fluid. Second, the acoustic source terms are used in computational aeroacoustics simulations to determine the acoustic field by solving the acoustic perturbation equations. To identify the contributions of the different source terms to the overall sound emission of the flames different source term formulations are considered in the computational aeroacoustics simulations. The results of various flames of increasing complexity are shown: harmonically excited laminar flames, a turbulent jet flame, and an unconfined and a confined swirl flame. The results show that in general the heat release source alone does not determine the acoustic emission of the flame. Only the acoustic emission of the unconfined swirl flame could be computed by the heat release source. To accurately predict the phase and the amplitude of the sound emission of the other flames the acceleration of density gradients occurring at the flame front must be included in the considered set of source terms.

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Wall-temperature effects on flame response to acoustic oscillations

Cited by 59 publications

References 77 publications

DNS of Intrinsic ThermoAcoustic modes in laminar premixed flames

DNS of Intrinsic ThermoAcoustic modes in laminar premixed flames

Joint experimental and numerical study of the influence of flame holder temperature on the stabilization of a laminar methane flame on a cylinder

Analysis of the sound sources of lean premixed methane–air flames

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