NO<sub>x</sub>Formation in Counter-Flow Opposed-Jet Diffusion CH<sub>4</sub>/Air Flames

Bonturi, S.; Pourkashanian, Mohamed; Williams, Alan; Oskam, Gareth W.; Wilson, Channing W.

doi:10.1080/00102209608935595

Cited by 18 publications

(7 citation statements)

References 3 publications

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“…These zones coincide with areas of significant NO 2 contributions. Bonturi et al (1996) also concluded in their work that a peak in NO 2 was found on the rich side of stoichiometric, with its presence in a similar region in mixture-fraction space to a peak in HO 2 radicals.…”

Section: Resultsmentioning

confidence: 88%

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Experimental Investigation of Oxygen-Enriched Lifted and Attached Turbulent Diffusion Flames

Williams

Howard

Patterson

et al. 2004

Inter J Ener Clean Env

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The interactions between turbulent fluid flow and chemical kinetics are examined experimentally in attached and lifted turbulent oxygen-enriched gaseous non-premixed flames by firing a methane jet vertically into a co-flowing oxidant shroud. Stable species, including nitrogen oxides, were measured using physical-probing techniques. Hydroxyl radical concentrations were monitored using laser-induced fluorescence (LIF). The level of oxygen enrichment in the shroud air was varied from 21% to 28% while maintaining constant average fuel-nozzle velocity and Reynolds number. Within the operating range, attached as well as lifted flames were observed. Physical and chemical differences in structure between attached and lifted flames are presented. With an increasing degree of oxygen, enrichment flames become shorter and more luminous in appearance. Attached flames appear more luminous with longer flame lengths. Significant amounts of oxygen were found on the fuel-rich side of the stoichiometric envelope in lifted flames, underscoring partially premixed characteristics near downstream locations.

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Section: Resultsmentioning

confidence: 88%

“…It has been concluded (Bonturi et al, 1996) that the significance of the prompt mechanism in the formation of NO x becomes more apparent as the strain rate within the flame increases. They also concluded that as the strain rate was reduced, the thermal NO mechanism was enhanced.…”

Section: Resultsmentioning

confidence: 99%

Experimental Investigation of Oxygen-Enriched Lifted and Attached Turbulent Diffusion Flames

Williams

Howard

Patterson

et al. 2004

Inter J Ener Clean Env

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“…Soot particles tend to increase radiative heat loss from the flame leading to a decrease in the flame temperature and eventually NO formation. 156 Pressure also has a significant effect on the NO formation and it was first numerically studied by Bonturi et al 157 in methane-air counterflow diffusion flames. At a constant strain rate, [NO] increased uniformly with an increase in pressure and prompt NO was observed to be the major contributor to NO formation followed by thermal NO.…”

Section: No Studiesmentioning

confidence: 99%

Advances in understanding combustion phenomena using non-premixed and partially premixed counterflow flames: A review

Ravikrishna

Sahu

2017

International Journal of Spray and Combustion Dynamics

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Counterflow flames provide an ideal platform for understanding the flame structure and as a model to study the effect of physical and chemical perturbations on the flame structure. This article reviews the advances made in the understanding of combustion dynamics and chemistry through experimental and numerical studies in counterflow non-premixed and partially premixed flames. Key contributions on fundamental aspects such as extinction, ignition and effect of perturbations on the stability of diffusion flames are first summarized and analysed. The review then focuses on the progress made in the understanding of the effect of inert particles and flame suppressants on the flame characteristics. A review of detailed studies on edge flames facilitates further understanding of local quenching and re-ignition phenomena in highly turbulent flames. The influence of radiation model and unsteady flow-conditions on the flame kinetics and dynamics along with work on NO x kinetics has been discussed. The review also outlines that specific experiments need to be carried out over a wide range of conditions for further understanding and validation of numerical models.

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“…The formation of NO in laminar counterflow diffusion flames has been studied mostly at atmospheric pressure by past researchers (Atreya et al, 1996;Bonturi et al, 1997;Blint, 1989, 1991;Hahn and Wendt, 1981;Li et al, 1997;Nishioka et al, 1994;Laurendeau, 1998, 2000;Ravikrishna et al, 1999;Sick et al, 1998). The only previous experimental work on NO measurements in high-pressure counterflow diffusion flames is our own work , which represents the first reported measurements of [NO] in such flames.…”

Section: Introductionmentioning

confidence: 95%

Quantitative Laser-Induced Fluorescence Measurements and Modeling of Nitric Oxide in High-Pressure (6–15 Atm) Counterflow Diffusion Flames

Ravikrishna

Naik²,

Cooper³

et al. 2004

Combustion Science and Technology

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Laser-induced fluorescence (LIF) measurements of NO concentration ([NO])have been obtained along the centerline of methane-air counterflow diffusion flames at 6 to 15 atm. This study is an extension of our previous work involving measurements of [NO] in similar flames at two to five atm, wherein we had used a counterflow premixed flame for calibration. For the flames studied here, a method based on computed overlap fractions is developed to calibrate [NO] measurements at higher pressures. The linear LIF measurements of [NO], which are corrected for variations in the electronic quenching rate coefficient, are compared with numerical predictions from an opposed-flow flame code utilizing two Gas Research Institute (GRI) chemical kinetic mechanisms (versions 2.11 and 3.0). The effect of radiative heat loss on code predictions is accounted for by using an optically thin radiation model. The revised GRI mechanism (version 3.0) offers a significant improvement in prompt-NO predictions for these flames compared to the older version (2.11), especially at pressures below eight atm. However, a consistent discrepancy remains in the comparisons, particularly at peak NO locations for pressures lower than six atm. The measurements display a continuing trend of decreasing NO concentration with increasing pressure at 6-15 atm as expected for flames dominated by prompt NO. The discrepancy between measurements and predictions decreases with rising pressure so that the revised GRI mechanism predicts [NO] with reasonable accuracy at pressures above six atm.

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NO_xFormation in Counter-Flow Opposed-Jet Diffusion CH₄/Air Flames

Cited by 18 publications

References 3 publications

Experimental Investigation of Oxygen-Enriched Lifted and Attached Turbulent Diffusion Flames

Experimental Investigation of Oxygen-Enriched Lifted and Attached Turbulent Diffusion Flames

Advances in understanding combustion phenomena using non-premixed and partially premixed counterflow flames: A review

Quantitative Laser-Induced Fluorescence Measurements and Modeling of Nitric Oxide in High-Pressure (6–15 Atm) Counterflow Diffusion Flames

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NOxFormation in Counter-Flow Opposed-Jet Diffusion CH4/Air Flames

Cited by 18 publications

References 3 publications

Experimental Investigation of Oxygen-Enriched Lifted and Attached Turbulent Diffusion Flames

Experimental Investigation of Oxygen-Enriched Lifted and Attached Turbulent Diffusion Flames

Advances in understanding combustion phenomena using non-premixed and partially premixed counterflow flames: A review

Quantitative Laser-Induced Fluorescence Measurements and Modeling of Nitric Oxide in High-Pressure (6–15 Atm) Counterflow Diffusion Flames

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NO_xFormation in Counter-Flow Opposed-Jet Diffusion CH₄/Air Flames