Strategies for quantitative NO-concentration and temperature measurements by NO LIF in high-pressure flames

摘要

At pressures above 10 atmospheres, attenuation of the excitation laser and fluorescence signal in the hot combustion gases and interference from molecular oxygen LIF causes significant problems for NO LIF. We present a detailed comparison of various strategies for NO-LIF exploring the choices of excitation and detection transitions in the A-X (0,0), (0,1), and (0,2) bands. Using spectroscopic measurements in laminar premixed methane/air flames at pressures between 1 and 60 bar, we discuss the advantages and problems of the detection strategies in terms of spectral purity, pressure and temperature influence, and susceptibility to laser and signal light attenuation. The selected strategies are then used for quantitative NO-concentration- and temperature-imaging in high pressure flames.