Strategies for laser-induced fluorescence detection of nitric oxide in high-pressure flames. II. A-X(0,1) excitation
In: Appl. Opt., Jg. 42 (2003) ; Nr. 12, S. 2031-2042
Zeitschriftenaufsatz / Fach: Maschinenbau
A-X(0,1) excitation is a promising new approach for NO laser-induced fluorescence (LIF) diagnostics at elevated pressures and temps. The first detailed spectroscopic investigations within this excitation band using wavelength-resolved LIF measurements in premixed methane/air flames at pressures between 1 and 60 bar and a range of fuel/air ratios is presented. Interference from O2 LIF is a significant problem in lean flames for NO LIF measurements, and pressure broadening and quenching lead to increased interference with increased pressure. Three different excitation schemes are identified that maximize NO/O2 LIF signal ratios, thereby minimizing the O2 interference. The NO LIF signal strength, interference by hot molecular. oxygen, and temperature dependence of the three schemes are investigated.