Laser-induced-fluorescence techniques have been used successfully for quantitative two-dimensional measurements of nitric oxide. NO A–X(0, 2) excitation at 248 nm recently found applications in internal-combustion engines. We assess the collisional processes that influence quantification of signal intensities in terms of saturation, rotational energy transfer, and line broadening, using laminar high-pressure methane/air and n-heptane/air flames at pressures as high as 80 bars (8 × 106 Pa). A calibration method that is applicable in technical combustion systems based on addition of NO to the burning flame is investigated for various air/fuel ratios and pressures and yields information about the influence of NO reburn processes.
© 1999 Optical Society of America
Original Manuscript: July 6, 1998
Revised Manuscript: December 22, 1998
Published: March 20, 1999
Christof Schulz, Volker Sick, Ulrich E. Meier, Johannes Heinze, and Winfried Stricker, "Quantification of NO A–X(0, 2) laser-induced fluorescence: investigation of calibration and collisional influences in high-pressure flames," Appl. Opt. 38, 1434-1443 (1999)