Comparative Study of the Effects of Nitrous Oxide and Oxygen on Ethylene Ignition

To explore the effects of N2O and O-2 on C2H4 ignition, ignition delay times of stoichiometric C2H4/O-2/N2O/Ar mixtures with mole blending ratios of N2O/(N2O + O-2) = 0, 50, 80, and 100% were measured in a high-pressure shock tube. Reflected shock conditions cover a range of pressures from 1.2 to10 atm and temperatures from 1090 to 1760 K. In addition, ignition delay times of C2H4/N2O/Ar mixtures are measured at pressures of 1.2-10 atm, equivalence ratios of 0.5-2.0, and temperatures of 1214-1817 K. The results indicate that, in the studied conditions, the ignition delay times of C2H4 greatly increase as the N2O concentration increases at a given pressure and temperature. Five recent literature models are tested against the new measured ignition delay times and show very small discrepancies among each other for the C2H4/N2O/Ar mixtures but exhibit significant discrepancies for the C2H4/N2O/O-2/Ar mixtures. Moreover, the kinetic analysis is performed to reveal the reason for the discrepancies among the five models and to investigate the different effects of N2O and O-2 on the C2H4 ignition.