Effects of air contamination on the combustion of hydrogen -: Effect of NO and NO2 addition on hydrogen ignition and oxidation kinetics

New kinetic results for the oxidation of hydrogen in diluted conditions, perturbed by the addition of various concentrations of NO or NO2 were obtained in a jet-stirred reactor. The experiments were performed over the temperature range 700-1150 K, for pressures of 1 to 10 atm, and equivalence ratios from 0.1 to 2.5. The experiments were performed at fixed residence time, tau, and variable temperature. Sonic probe sampling at low pressure followed by on-line and off-line chemical analyses (gas chromatography and FTIR) were used to follow the reaction. A detailed kinetic modeling of the present experiments was performed using the proposed kinetic scheme. Further validations of this kinetic reaction mechanism were performed simulating the ignition of hydrogen-air and hydrogen-NOx-air mixtures, and the burning velocities of hydrogen-air mixtures. The present modeling results agreed well with the flame data and the ignition data of H-2-air-NO mixtures but disagree with the mixtures containing NO2. The present results support the low literature value of the rate constant for the reaction of NO2 with H-2 whereas a much higher rate constant is needed to fit the ignition delays of the H-2-air-NO2 mixtures.