Flame structure studies of premixed ammonia/hydrogen/oxygen/argon flames: Experimental and numerical investigation

Structures of diluted arnmonia-hydrogen-oxygen-argon flame have-been investigated at low pressure by molecular beam mass spectrometry to study the effect of the initial hydrogen content, the equivalence ratio and the working pressure on ammonia combustion. Excluding a slight effect on the NO formation, the initial hydrogen content does not have a significant impact on the composition of the burned gases. Around stoichiometric conditions, a decrease of the equivalence ratio strongly increases the NO formation. Furthermore, at high temperature, the NO formation is favoured as it has been noticed in flames where, due to different heat transfer, the maximum temperature increases with a decrease of pressure. The best agreement of the numerical simulation with the experimental results has been obtained by using Konnov's mechanism excepted for NH(2) and N(2)O. the impact of the main individual reaction pathways is very similar in all investigated flames. (C) 2009 The Combustion Institute. Published by Elsevier Inc. All rights reserved.