Experimental and modeling study of NO formation in methyl acetate + air flames

Abstract

Premixed laminar flat non-stretched flames of methyl acetate + air have been studied at atmospheric pressure. The heat flux method was employed to stabilize the flames over equivalence ratios ɸ = 0.7–1.5 at initial gas temperatures from 298 to 348 K. The laminar burning velocities of methyl acetate + air mixtures have been measured at these conditions and compared with the literature data. Laser-induced fluorescence was used to measure NO concentrations in the post-combustion region of the flames at 298 K. The detailed kinetic mechanism of the authors was extended by the reactions of methyl acetate, mostly relying on the model developed by Ahmed et al. (2019). The mechanism was tested against selected literature data from measurements in a shock tube and jet-stirred reactor. Moreover, it was compared with new measurements of the laminar burning velocity and NO concentrations in methyl acetate flames. In all cases, good agreement between the experimental and modeling results was observed. A comparison with LIF measurements obtained for methane + air flames at the same conditions shows that NO concentrations in methyl acetate flames are lower than those in methane + air flames both in stoichiometric and rich mixtures. These differences were interpreted using sensitivity and rate-of-production analyses of NO formation via different routes.