Laser-induced fluorescence and Rayleigh scattering measurements were made in well-stabilized, laminar partially premixed Bunsen-type methane/air flames. Simultaneous Rayleigh scattering (temperature) and laser-induced fluorescence (flame radical concentration) enable precise determination of the position of CH and OH radical structures in the gradient of the flame temperature. The OH and CH structures in the straight walls of the premixed inner flame cone are well described by models incorporating detailed flame chemistry and one-dimensional transport. Near the tip of the inner cone in regions of increased flame stretch, at richer stoichiometries of the premixed portion of the flames, and in flames perturbed by a metal insert, the measured structure of CH and OH deviates from this simple description. CH concentrations predicted by the model depend on flow rate, thus suggesting the importance of strain rate to prompt NOx formation in these flames.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)
- Physics and Astronomy(all)