Prompt-NO formation in methane/oxygen/nitrogen flames seeded with oxygenated volatile organic compounds: Methyl ethyl ketone or ethyl acetate

Experimental and numerical study of the role of NCN in prompt-NO formation in low-pressure CH4–O2–N2 and C2H2–O2–N2 flames

“…8a) and NCN (Fig. 8b) mole fractions at their peak locations for a wide range of experimental conditions [17,36,42,43]. NO and CH mole fractions are shown to be overall proportional to each other in Fig.…”

“…The CRD decay time was found to be 460 ns with the laser tuned OFF resonance and 275 ns with the laser tuned ON resonance (with the P 1 (8) line) at the CH peak location. From the CRD decay times measured ON and OFF resonance, one obtains the integrated absorptivity according to the procedure previously described [36,37]. From this integrated absorptivity, one obtains the absolute number density of the excited rotational level ( J 00 = 8), knowing the absorption length (l s = 6 cm) and the oscillator strength for absorption (f J 00 J 0 = 4.40 Â 10 À3 and 4.57 Â 10 À3 , for the lines P 1 (8) and P 2 (8), respectively).…”

“…Kinetic analysis is essentially based on the rates of production and consumption. Rates of production/consumption of each species are systematically computed using the appropriate subroutines in the Chemkin II package as previously described [36].…”

“…Indeed, it was shown that up to 600 ppm of NO could be substituted for N 2 without NO reburning. Measurements were performed 20 mm above the burner following a procedure previously described [36,37]. At that location, taking into account the slight effect of dilution (lower than 4% in the flame CH 4 (1.00) and null in the C 2 H 2 (1.00)) [43], the native NO was found to be 27.4 and 9.6 ppm (with an accuracy of 10%), respectively, in C 2 H 2 and CH 4 stoichiometric flames.…”

Demonstration of a burner for the investigation of partially premixed low-temperature flames

“…With regard to highermolecular species, traces of C 4 H 2 were detected. In subsequent experimental work in flat, premixed methane flames, mostly at re- duced pressure, emphasis was often placed on the detection of specific intermediates including OH, CH, CH 3 and HCO [56,57], or on aspects of NO x formation chemistry, most recently including NCN radicals [58]. Several mass-spectrometric investigations of low-pressure methane-oxygen flames [50,51] provided an overview of the species composition.…”