Effect of Ammonia on Two-stage Ignition Characteristics of N-Heptane
The influence of ammonia on the two-stage ignition characteristics of n-heptane at low and medium temperature was studied.By analyzing the concentration distribution of key components,the chemical reaction rate and reaction path of important elementary reactions,the influence mechanism of ammonia on the chemical kinetics of n-heptane ignition in the first stage(low temperature)and the second stage(high temperature)was revealed.The results show that in the first stage,the addition of ammonia will change the oxidation path of n-heptane and make the partial decomposition reaction change into isomerization reaction.At the same time,ammonia reacts with free radicals HO2,OH,O and H to reduce the consumption of n-heptane in the first stage.In the second stage,the concentra-tion of OH,O and H radicals decreased after the addition of ammonia,while the overall reaction path of n-heptane remained basically unchanged.According to the reaction path,N2O mainly reacts with CO,and then N2 and CO2 are generated.When the mixing ratio of ammonia increases,the emission of NOx decreases.
ammonia/n-heptaneignition delay timechemical kinetics analysisignition process
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