Pdf calculations of turbulent lifted flames of H<sub>2</sub>/N<sub>2</sub>fuel issuing into a vitiated co-flow

Masri, Assaad R.; Cao, Renfeng Richard; Pope, Stephen B.; Goldin, Graham M.

doi:10.1088/1364-7830/8/1/001

Cited by 114 publications

(83 citation statements)

References 38 publications

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“…Also in lifted flames, auto-ignition related chemistry strongly affects the flame lift-off height (e.g. [1]). Typically, this concerns chemistry at relatively low temperature, in the order of 1000K and less.…”

Section: Nomenclaturementioning

confidence: 99%

Analysis of auto-ignition of heated hydrogen–air mixtures with different detailed reaction mechanisms

Stanković

Merci

2011

Combustion Theory and Modelling

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Section: Nomenclaturementioning

confidence: 99%

Analysis of auto-ignition of heated hydrogen–air mixtures with different detailed reaction mechanisms

Stanković

Merci

2011

Combustion Theory and Modelling

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“…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%

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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“…The co-flow turbulence lengthscale was chosen to be 1.6mm, the size of the holes in the outer disk. The turbulence intensity is 5% [8,28]. The simulations are started from a developed inert flow field at time t 0 .…”

Section: Berkeley Casementioning

confidence: 99%

“…In [28,29], a RANS-based PDF method was applied and it was reported that the predicted ignition delay times were very sensitive to the chemical kinetic rates (for the case of [8]). In [21] we illustrate that the sensitivity for the test case at hand [9] is not the same as for case of [8], particularly due to differences in fuel composition, although the main trends are quite similar.…”

Section: Sensitivity To the Chemistry Mechanismmentioning

confidence: 99%

“…In the present paper, we compare only the mechanisms of [22][23][24] in 3D LES-CMC simulations. The sensitivity of RANS-PDF predictions of the auto-igniting jet in vitiated air [8] to the detailed hydrogen mechanism has already been reported [27][28][29]. The test case of [8] differs from [9] in composition of the fuel and co-flow, as well as in geometry and temperatures (e.g.…”

Section: Introductionmentioning

confidence: 96%

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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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Pdf calculations of turbulent lifted flames of H₂/N₂fuel issuing into a vitiated co-flow

Cited by 114 publications

References 38 publications

Analysis of auto-ignition of heated hydrogen–air mixtures with different detailed reaction mechanisms

Analysis of auto-ignition of heated hydrogen–air mixtures with different detailed reaction mechanisms

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

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Pdf calculations of turbulent lifted flames of H2/N2fuel issuing into a vitiated co-flow

Cited by 114 publications

References 38 publications

Analysis of auto-ignition of heated hydrogen–air mixtures with different detailed reaction mechanisms

Analysis of auto-ignition of heated hydrogen–air mixtures with different detailed reaction mechanisms

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

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Pdf calculations of turbulent lifted flames of H₂/N₂fuel issuing into a vitiated co-flow