基于反应力场分子模拟的乙烯燃烧自由基与氮气相互作用研究

Interaction Between Produced Radicals During Ethylene Combustion and Nitrogen Molecules Based on Reaxff Molecular Dynamics Simulation

采用反应力场分子动力学(ReaxFF-MD)方法,模拟了富燃料条件下乙烯在空气中的燃烧以及燃烧产生的自由基与氮气的相互作用.采用ReacNetGenerator程序提取反应网络,结合自编后处理程序确定反应网络上的相关反应,分析了乙烯燃烧的反应路径,以及自由基与N_(2)的相关反应和NO的生成路径.结果表明,乙烯燃烧路径与已报道的通过乙烯燃烧反应机理模拟得到的燃烧路径一致,说明用ReaxFF-MD方法模拟乙烯高温燃烧有效而可靠;乙烯在富燃料条件下燃烧产生的CH,C_(2)H,C_(2),C_(2)O自由基是瞬发型NO生成的重要反应物.这些自由基与N_(2)的反应和NO的生成路径,为构建乙烯和大分子碳氢燃料燃烧氮氧化物排放的反应机理提供了重要参考.

The combustion of C_(2)H_(4) in air and the interaction between produced radicals during combustion and nitrogen molecules were studied using reactive force field molecule dynamics(ReaxFF-MD)method under fuel-rich condition at 3200 K.The key information,including the reaction path of ethylene combustion,the reactions of produced radicals during combustion with N_(2),and formation paths of NO,were obtained by combining reaction networks extracted by ReacNetGenerator program with the related reactions obtained though the code developed by our group.The results showed that the combustion path of ethylene is consistent with that obtained by previous kinetic simulation using those reaction mechanisms of ethylene combustion,indicating that the ReaxFF-MD method is effective and reliable to simulate the high temperature combustion of ethylene.For fuel-rich flame of ethylene,it has been suggested that the CH,C_(2)H,C_(2),and C_(2)O radicals could become important in prompt NO.The reactions of these radicals with N_(2) and formation paths of NO can provide important clues for the construction of reaction mechanism of nitrogen oxide emission during the combustion of ethylene and larger hydrocarbons.