Free radical concentration measurements in nitric oxideacetylene flames

Flat flames of premixed acetylenenitric oxide have been stabilized on a low-pressure burner, operating at 80 Torr, in the temperature range of 2800–3100K. Two flames were investigated, one fuel rich and the other of stoichiometric composition. Temperature profiles and concentration profiles of free radicals species and of the stable products of reaction were determined in the reaction and postreaction zones using spectroscopic techniques. NO, CN, NH, C 2, CH, and OH were measured by absorption, CO 2 and H 2O were measured from the intensity of their infrared emission bands. The analysis of the data indicates that the reactions of NO with C 2, CH, CN, and NH are extremely fast and are responsible for the majority of NO destruction in the early part of the flame. Later in the flame the reduction of NO continues, very likely, according to a Zeldovich reverse type mechanism.