Quantitative measurements of the CH radical in sooting diffusion flames at atmospheric pressure

C. Moreau (1) , E. Therssen (1) , Pascale Desgroux (1) , J.F. Pauwels (1) , A. Chapput (2) , M. Barj (2)

1 PC2A - Physicochimie des Processus de Combustion et de l’Atmosphère - UMR 8522
2 LASIRE - Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516

The potential of Laser Induced Fluorescence detection of the CH radical using C–X (0–0) excitation is investigated in a sooting methane/air diffusion flame at atmospheric pressure. Fluorescence is detected using the very narrow (<0.4 nm) Q-branch of the C–X (0–0) band, which enables the measurement of CH in sooting flames without interference from PAH fluorescence and soot emissions. Absolute concentrations are obtained using Cavity Ring Down Spectroscopy. 1D CH profiles in the sooting zone are recorded using a CCD camera with an excellent signal-to-noise ratio. The C–X (0–0) excitation associated with Q-branch detection is shown to be three times more efficient than the B–X scheme.

C. Moreau, E. Therssen, Pascale Desgroux, J.F. Pauwels, A. Chapput, et al.. Quantitative measurements of the CH radical in sooting diffusion flames at atmospheric pressure. Applied Physics B - Laser and Optics, 2003, 76, pp.597-602. ⟨10.1007/s00340-002-1085-3⟩. ⟨hal-00274730⟩