An investigation of the structure and the NO formation characteristics of partially premixed methane flames using planar laser induced fluorescence

The formation of nitric oxide (NO) in hydrocarbon flames has not yet been clearly understood. NO is produced through the thermal NO (Zeldovich mechanism), the N/sub 2/O-intermediate mechanism and the prompt NO (Fenimore mechanism) in a flame. For partially premixed flames, the thermal NO and the prompt NO mechanism are generally considered as major sources for the total NO, and the amount of NO formed from each of these mechanisms depends on the temperature and the equivalence ratio of the flame. Recent studies suggest that the structure of partially premixed flames and the distribution of CH, OH and NO in flames should be considered in understanding the NO production characteristics. In the present study, the characteristics of NO production in partially premixed methane flames are experimentally investigated using planar LIF imaging techniques.