O₂ Concentration Measurement in a Laminar Diffusion Flame by Laser-Induced Florescence

Abstract

Oxygen molecule (O₂) in a flame is a critical molecule for the formation and oxidation processes of polycyclic aromatic hydrocarbon (PAHs) and particulate matter (PM). Then, it is important to know a spatial distribution of O₂ concentration in a flame. In this study, a laser-induced O₂ fluorescence technique was proposed. Oxygen molecule concentration was obtained with O₂-LIF signal from O₂ molecule excited by an ArF excimer laser. Excitation wavelength for maximizing O₂-LIF signal from a flame was optimized experimentally. Relationship of O₂ concentration regarding O₂-LIF signal and flame temperature was derived from a calibration experiment using hot air thermometry. In order to validate the technique, a spatial distribution of O₂ concentration in a propane diffusion flame was measured by the present technique and an oxygen analyzer via a gas sampling. Oxygen molecule concentration obtained with O₂-LIF technique showed good correlation as compared with that of oxygen analyzer measurement.