Hydrogen nitrous oxide kinetics -: Implications of the NxHy species

Dilute mixtures of hydrogen and nitrous oxide in nitrogen were studied in a large-diameter flow reactor at 3 atm and 995 K. The consumption of H-2 and N2O as well as the formation of H2O and the intermediate species profiles of NH3 and NO were all measured experimentally. A detailed chemical mechanism is developed and compared with the experimental measurements. From knowledge of the NH3 and NO intermediate species profiles, results are presented which indicate that N2Hx and NHx species and reactions are necessary to predict the overall reaction rate of pure H-2/N2O/N-2 mixtures at these temperatures. Numerical predictions without this chemistry can be too fast by as much as a factor of 2. Experiments were also conducted with quantities of NO and NH3 added to the initial mixtures in order to investigate the inhibitory strengths of these species and to further constrain the model validation. Based on these parametric studies, an estimate is given for the reate constant of NO + H + M = HNO + M with nitrogen as the collision partner. (C) 1998 by The Combustion Institute.