N₂O对乙烯自点火敏化作用的实验和理论研究

Aiming at probing the direct interaction between unsaturated hydrocarbons and NO_x in hydrazine rocket propellant, the auto-ignition process of ethylene (C₂H₄) and N₂O mixtures was studied experimentally and theoretically. The ignition delay time of stoichiometric C₂H₄/N₂O/O₂/Ar with blending ratios of N₂O/(N₂O+O₂)=0%, 50%, 80% and 100% was measured in the reflected shock conditions covering pressure range of 0.12-1.01 MPa and temperature range of 1 214-1 817 K in a shock tube. Experimental results show that compared to O₂, the reactivity of C₂H₄ is significantly decreased by N₂O, resulting in longer ignition delay time, and this inhibition effect increases with the concentration of N₂O, meaning that the ignition delay presents a non-linear dependence on N₂O addition. Simulation results reveal that only Aramco-Z model shows a reasonable agreement with the measurements. Direct interaction between N₂O and C₂H₄ appears to be not favorable. Longer ignition delay time caused by the addition of N₂O is due mainly to the reduction in the reaction rate of C₂H₃+O₂ and the concentration of free radical pool.