NO formation in high pressure premixed flames: Experimental results and validation of a new revised reaction mechanism

• Published in: Fuel (Guildford) Vol. 260; p. 116331
• Main Authors: de Persis, Stéphanie, Pillier, Laure, Idir, Mahmoud, Molet, Julien, Lamoureux, Nathalie, Desgroux, Pascale
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.01.2020; Elsevier BV; Elsevier
• Subjects: Computer simulation; Consumption; Counterflow; Engineering Sciences; Equivalence ratio; Fluorescence; High pressure; High pressure flames; Kinetic analysis; Laser Induced Fluorescence; Methane; Methane combustion; NOx formation; Oxidation; Premixed flames; Pressure; Pressure effects; Reaction mechanisms; Reactive fluid environment; Sensitivity analysis; NOx formation; Kinetic analysis; High pressure flames; Methane combustion; Laser Induced Fluorescence
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2019.116331

•Quantitative NO mole fraction profiles are measured by Laser Induced Fluorescence.•Simulations were performed using GDFkin®3.0_NOmecha2.0 and Klippenstein mechanisms.•Both mechanisms are able to predict NO correctly in lean and stoichiometric flames.•In rich flames, GDFkin®3.0_NOmecha2.0 gives the best predictions.•Kinetic analyses allow identifying the main NO formation pathways. This paper presents an experimental and modelling study of NO formation in high pressure premixed flames. Experiments were performed in a high-pressure counterflow burner in which laminar premixed CH4/air flames were stabilised at equivalence ratios of E.R = 0.7, 1 and 1.2 and for pressures varying from 0.1 to 0.7 MPa. We report quantitative NO mole fraction profiles measured by Laser Induced Fluorescence. The effects of pressure and equivalence ratio on NO formation are discussed. These results are compared to the simulations using two reaction mechanisms: NOmecha2.0 associated to a detailed mechanism for methane oxidation: GDFkin®3.0 and the mechanism from Klippenstein et al., which is the most recent high-pressure NOx formation mechanism available in the literature. In general, both mechanisms are able to predict NO correctly in lean and stoichiometric high pressure flames; however, in rich flames, GDFkin®3.0_NOmecha2.0 gives the best predictions. The performances of these mechanisms are also tested on NO measurements in high-pressure flames from the literature. A kinetic analysis is then presented to identify the main pathways that lead to the formation and consumption of NO and highlight the differences between the two mechanisms, as well as a sensitivity analysis to identify important reactions that influence the formation/consumption of NO in our high pressure flames.