氨与乙醇高温自着火特性试验与动力学分析

The ignition delay time of ammonia/ethanol mixtures was studied by using shock tube at equivalent ratios of 0.5,1.0 and 2.0,temperatures of 1250～1980 K,and pressures of 0.14 and 1.0 MPa,the molar fraction of ethanol in the total fuel is 0,5%,10%and 30%,respectively.A new ammonia/ethanol model(NH3-E)was proposed,which was proved to be able to predict the experimental results reliably,and the chemical reaction kinetics were performed based on it.The results showed that ethanol has a significant nonlinear promoting effect on the ignition delay time of ammonia.The ignition delay time of ammonia/ethanol mixture can be shortened by more than 65%when the mixture ratio is 5%(molar fraction)of ethanol.The early consumption of ethanol rapidly produces a large number of active free radicals,which is the key factor to promote ammonia combustion.With the increase in the ethanol blending ratio,ethanol consumption becomes more important through H-abstraction.With the addition of a larger percentage(30%)of ethanol,the concentration of CH3 increases in the free radical pool and reacts with NH2 to produce highly toxic species of cyanide.