Nitric Oxide Concentration and Lifetime Measurements Using Picosecond Time-Resolved Laser-Induced Fluorescence

摘要

We report quantitative nitric oxide (NO) fluorescence lifetime and concentration measurements in a laminar counterflow partially premixed methane/air flame by employing the picosecond time-resolved laser-induced fluorescence (PITLIF) technique. By choosing a narrow band detection (2-nm) at 236 nm and centering the excitation wavelength at 226.03 nm, we excited the γ(0,0) band and minimized the interferences from the O{sub}2 Schumann-Runge bands. The system is capable of a 3 ppm detection limit on the outer edges of the NO profile and has a spatial resolution of 300μm. The measured NO concentration profile is in very good agreement with those based on detailed chemical-kinetic simulations. Moreover, the quenching corrected peak NO concentration agrees to within 4% of the prediction. Measured NO fluorescence lifetimes compare favorably with predictions within uncertainties of current quenching cross-section models. The potential implications of current measurements and their extension to turbulent flame applications are discussed.