A numerical study of auto-ignition in turbulent lifted flames issuing into a vitiated co-flow

Gordon, Robert L.; Masri, Assaad R.; Pope, Stephen B.; Goldin, Graham M.

doi:10.1080/13647830600903472

Cited by 111 publications

(109 citation statements)

References 20 publications

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“…However, in the RANS-transported PDF of [22] or in the LES-CMC of [33], the budget analysis leads to the conclusion that autoignition is the main stabilisation mechanism for all coflow temperatures considered. Figure 18 shows two qualitatively different flames obtained with our model at low or high coflow temperature (as shown in the figure, the same trend is observed when usingω c orẎ c ).…”

Section: Influence Of σmentioning

confidence: 99%

“…In order to deal with realistic conditions while involving a small number of chemical species, we consider a steady lifted H 2 /N 2 turbulent jet flame in a coflow of hot products at atmospheric pressure (the vitiated co-flow burner developed by Dibble and co-workers), first measured at Berkeley university by Cabra et al [16,17] and later at Sydney university at different operating conditions [18,19]. This flame has mainly been modelled in a RANS framework using transported PDF methods with different mixing models [16,[20][21][22][23][24][25][26][27][28]. A first CMC calculation of this flame was reported in [29].…”

Section: Introductionmentioning

confidence: 99%

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RANS modelling of a lifted H2/N2 flame using an unsteady flamelet progress variable approach with presumed PDF

Naud

Novella

Pastor

et al. 2015

Combustion and Flame

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Elsevier Naud, B.; Novella Rosa, R.; Pastor Enguídanos, JM.; Winklinger, JF. (2015). RANS modelling of a lifted H2/N2 flame using an unsteady flamelet progress variable approach with presumed PDF. Combustion and Flame. 162 (4) AbstractAn unsteady flamelet / progress variable (UFPV) approach is used to model a lifted H 2 /N 2 flame in a RANS framework together with presumed PDF. We solve the unsteady flamelets both in physical space and in mixture fraction space. We show that in the former case, the scalar dissipation rate profile strongly varies in time (while it is assumed to be fixed in time in the latter). However, this does not result in significant qualitative differences in the corresponding flamelet libraries. The progress variable is carefully defined, including both the main combustion product (H 2 O) and a key radical species in ignition process (HO 2 ). The presumed-PDF model is proposed in terms of the non-normalised progress variable, without assuming its statistical independence with mixture fraction. We introduce a modelled transport equation for the mean progress variable which is consistent with the basic underlying UFPV assumption, derived from the Lagrangian flamelet model. The influence of different model parameters on the results for the mean temperature and mean species mass fractions and their fluctuations is discussed. Good results are obtained for the conditions of the considered lifted flame where detailed experimental data is available. However, at low coflow temperature the modelled flame lift-off height is shorter than expected.

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Section: Influence Of σmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

RANS modelling of a lifted H2/N2 flame using an unsteady flamelet progress variable approach with presumed PDF

Naud

Novella

Pastor

et al. 2015

Combustion and Flame

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“…In Fig. 2, the simulation results are compared with the data measured independently by Cabra et al [8], Gordon et al [10] and Wu et al [42]. The Gordon et al results (a) and (b) refer to measurements taken in two separate experiments.…”

Section: Berkeley Casementioning

confidence: 85%

“…The Berkeley burner [8,10] consists of a fuel jet nozzle and a surrounding perforated disk. The jet nozzle inner diameter is 4.57mm (d) and the wall thickness is 0.89mm.…”

Section: Berkeley Casementioning

confidence: 99%

“…We illustrate below that all these regimes are encountered with our LES-CMC approach. The Berkeley and Sydney flame [8,10] shows a continuous sheet, with only the base having a fragmented nature -see the images in [14,15]. The Cambridge burner for some conditions shows a lifted or attached flame, but in others it shows a fragmented flame ('spots') everywhere.…”

Section: Introductionmentioning

confidence: 99%

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LES-CMC Simulations of Different Auto-ignition Regimes of Hydrogen in a Hot Turbulent Air Co-flow

Stanković

Mastorakos

Merci

2013

Flow Turbulence Combust

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In: Flow, Turbulence and CombustionTo refer to or to cite this work, please use the citation to the published version:I. Stankovic, E. Mastorakos and B. Merci (2013). LES-CMC simulations of different autoignition regimes of hydrogen in a hot turbulent air co-flow. Flow, Turbulence and Combustion. 90:583-604. DOI: 10.1007/s10494-013-9443-2 Noname manuscript No. (will be inserted by the editor) LES-CMC simulations of different auto-ignition regimes of hydrogen in a hot turbulent air co-flowReceived: date / Accepted: date Abstract Large-Eddy Simulation (LES) results in combination with first-order Conditional Moment Closure (CMC) are presented for a hydrogen jet, diluted with nitrogen, issued into a turbulent co-flowing hot air stream. The fuel mixes with the co-flow air, ignites and forms a lifted-like flame. Global trends in the experimental observations are in general well reproduced: the auto-ignition length decreases with increase in co-flow temperature and increases with increase in co-flow velocity. In the experiments, the co-flow temperature was varied, so that different auto-ignition regimes, including low Damköhler number situations, were obtained (no ignition, random spots, flashback and lifted flame). All regimes are recovered in the simulations. Auto-ignition is found to be the stabilizing mechanism. The impact of different detailed chemistry mechanisms on the auto-ignition predictions is discussed. With increasing air temperature, the differences between the mechanisms considered diminish. The evolution of temperature, H 2 O, H, HO 2 and OH from inert to burning conditions is discussed in mixture fraction space.

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Probability Density Function Modeling of Turbulent Spray Combustion

Humza

Gutheil

2014

Experiments and Numerical Simulations of Turbulent Combustion of Diluted Sprays

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A numerical study of auto-ignition in turbulent lifted flames issuing into a vitiated co-flow

Cited by 111 publications

References 20 publications

RANS modelling of a lifted H2/N2 flame using an unsteady flamelet progress variable approach with presumed PDF

RANS modelling of a lifted H2/N2 flame using an unsteady flamelet progress variable approach with presumed PDF

LES-CMC Simulations of Different Auto-ignition Regimes of Hydrogen in a Hot Turbulent Air Co-flow

Probability Density Function Modeling of Turbulent Spray Combustion

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