NO2 chemiluminescent emission from flames influenced by acoustic noise

The effect of acoustic noise on combustion is investigated from the perspective of NOx emissions. A robust, plug-in probe that exploits the natural emission signal from the combustion gases, and which can have practical relevance, is used. Acoustically pulsed flames are stabilized on aburner, and NO2 chemiluminescence is measured with an intensified detector at various frequencies. The results indicate the NO2 emission increases in noisy flames at certain frequencies more significantly than others. Noise at higher frequencies in the range 0.8≈1 kHz effects the nitrogen chemistry in stoichiometric flames (ϕ=1), but not that in lean flames (ϕ-0.7 and 0.8).