VISUALIZATION OF CN BY THE USE OF PLANAR LASER-INDUCED FLUORESCENCE IN A CROSS-SECTION OF AN UNSEEDED TURBULENT CH4 AIR FLAME

CN is known to be the important species in forming NOx in hydrocarbon- air flames, and we describe the qualitative mapping of the CN distribu tion of the order of less than 1 in 10(6) at atmospheric pressure in a cross section of an unseeded turbulent CH4-air flame by the use of a single-shot laser pulse with planar laser-induced fluorescence. We obt ained the results by comparing the different excitation-detection sche mes to find the most appropriate scheme for visualization. In addition , the images obtained have good spatial resolution of 200 mu m. Based on a laminar flame experiment with the same optical systems, it is obs erved that the CN distribution zone is located outside of the inner co ne even at atmospheric pressure.