The effects of composition on burning velocity and nitric oxide formation in laminar premixed flames of CH4 + H2 + O2 + N2

Coppens, Fhv; Ruyck, de J; Konnov, Alexander A.

doi:10.1016/j.combustflame.2007.02.004

Cited by 171 publications

(105 citation statements)

References 30 publications

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“…The set of rate constants and thermochemical data of our mechanism comes from combustion chemistry. More specifically, it consists of a C/H/O reaction base developed for industrial applications (Fournet et al 1999;Bounaceur et al 2010) which has been validated for species containing up to 2 carbon atoms and a nitrogen base constructed to deal with NO x compounds and other nitrogen-containing species (Coppens et al 2007;Konnov 2009). The mechanism has been validated against numerous combustion experiments over a wide range of temperature (300-2500 K) and pressure (0.01-100 bar), and it has been found suitable to model the atmospheric chemistry of hot Jupiters (Venot et al 2012).…”

Section: The Chemical Modelmentioning

confidence: 99%

The impact of atmospheric circulation on the chemistry of the hot Jupiter HD 209458b

Agúndez

Venot

Iro

et al. 2012

A&A

142

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We investigate the effects of atmospheric circulation on the chemistry of the hot Jupiter HD 209458b. We use a simplified dynamical model and a robust chemical network, as opposed to previous studies which have used a three dimensional circulation model coupled to a simple chemical kinetics scheme. The temperature structure and distribution of the main atmospheric constituents are calculated in the limit of an atmosphere that rotates as a solid body with an equatorial rotation rate of 1 km s −1 . Such motion mimics a uniform zonal wind which resembles the equatorial superrotation structure found by three dimensional circulation models. The uneven heating of this tidally locked planet causes, even in the presence of such a strong zonal wind, large temperature contrasts between the dayside and nightside, of up to 800 K. This would result in important longitudinal variations of some molecular abundances if the atmosphere were at chemical equilibrium. The zonal wind, however, acts as a powerful disequilibrium process. We identify the existence of a pressure level of transition between two regimes, which may be located between 100 and 0.1 mbar depending on the molecule. Below this transition layer, chemical equilibrium holds, while above it, the zonal wind tends to homogenize the chemical composition of the atmosphere, bringing molecular abundances in the limb and nightside regions close to chemical equilibrium values characteristic of the dayside, i.e. producing an horizontal quenching effect in the abundances. Reasoning based on timescales arguments indicates that horizontal and vertical mixing are likely to compete in HD 209458b's atmosphere, producing a complex distribution where molecular abundances are quenched horizontally to dayside values and vertically to chemical equilibrium values characteristic of deep layers. Either assuming pure horizontal mixing or pure vertical mixing, we find substantial variations in the molecular abundances at the evening and morning limbs, up to one order of magnitude for CH 4 , which may have consequences for the interpretation of transmission spectra that sample the planet's terminator of hot Jupiters.

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Section: The Chemical Modelmentioning

confidence: 99%

The impact of atmospheric circulation on the chemistry of the hot Jupiter HD 209458b

Agúndez

Venot

Iro

et al. 2012

A&A

142

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“…In Figure 4b, measured laminar burning velocities are presented as a function of the hydrogen content for an equivalence ratio of 1.1 and these results are compared to those of the literature (23)(24)(25)(26)(27). Our measurements are in good agreement with these data, at least with those which have been recently obtained (24)(25)(26)(27). The agreement is very good from 0 to 68% of H 2 with the results of the only study in which such a large H 2 content has been used (26).…”

Section: Laminar Flame Velocity Of Hydrogen-enriched Methane Mixturesmentioning

confidence: 99%

“…Thus, we have used the following correlation proposed by Coppens et al (25) for the mixtures of methane with another gas:…”

Section: Correlation For Mixturesmentioning

confidence: 99%

Measurements of Laminar Flame Velocity for Components of Natural Gas

et al. 2011

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This paper presents new experimental measurements of the laminar flame velocity of components of natural gas, methane, ethane, propane, and n-butane as well as of binary and tertiary mixtures of these compounds proposed as surrogates for natural gas. These measurements have been performed by the heat flux method using a newly built flat flame adiabatic burner at atmospheric pressure. The composition of the investigated air/hydrocarbon mixtures covers a wide range of equivalence ratios, from 0.6 to 2.1, for which it is possible to sufficiently stabilize the flame. Other measurements involving the enrichment of methane by hydrogen (up to 68%) and the enrichment of air by oxygen (oxycombustion techniques) were also performed. Both empirical correlations and a detailed chemical mechanism have been proposed, the predictions being satisfactorily compared with the newly obtained experimental data under a wide range of conditions.

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“…It has been shown that hydrogen enrichment can improve flame stability and thus reduce NO x f o r m a t i o ni np r e m i x e dfl a m e s [1][2][3][4][5], as well as increase burning velocity [6][7][8]. For diffusion combustion, hydrogen enrichment can suppress the formation of soot particles [9,10] and shorten ignition delay [11,12].…”

Section: Introductionmentioning

confidence: 99%

A numerical study on the effect of hydrogen/reformate gas addition on flame temperature and NO formation in strained methane/air diffusion flames

Guo¹,

Neill²

2009

Combustion and Flame

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A numerical study on the effect of hydrogen/reformate gas addition on flame temperature and NO formation in strained methane/air diffusion flames Guo, Hongsheng; Neill, W. Stuart This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. This paper investigates the effects of hydrogen/reformate gas addition on flame temperature and NO formation in strained methane/air diffusion flames by numerical simulation. The results reveal that flame temperature changes due to the combined effects of adiabatic temperature, fuel Lewis number and radiation heat loss, when hydrogen/reformate gas is added to the fuel of a methane/air diffusion flame. The effect of Lewis number causes the flame temperature to increase much faster than the corresponding adiabatic equilibrium temperature when hydrogen is added, and results in a qualitatively different variation from the adiabatic equilibrium temperature as reformate gas is added. At some conditions, the addition of hydrogen results in a super-adiabatic flame temperature. The addition of hydrogen/reformate gas causes NO formation to change because of the variations in flame temperature, structure and NO formation mechanism, and the effect becomes more significant with increasing strain rate. The addition of a small amount of hydrogen or reformate gas has little effect on NO formation at low strain rates, and results in an increase in NO formation at moderate or high strain rates. However, the addition of a large amount of hydrogen increases NO formation at all strain rates, except near pure hydrogen condition. Conversely, the addition of a large amount of reformate gas results in a reduction in NO formation.Crown

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The effects of composition on burning velocity and nitric oxide formation in laminar premixed flames of CH4 + H2 + O2 + N2

Cited by 171 publications

References 30 publications

The impact of atmospheric circulation on the chemistry of the hot Jupiter HD 209458b

The impact of atmospheric circulation on the chemistry of the hot Jupiter HD 209458b

Measurements of Laminar Flame Velocity for Components of Natural Gas

A numerical study on the effect of hydrogen/reformate gas addition on flame temperature and NO formation in strained methane/air diffusion flames

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