The role of methylene in prompt NO formation
The role of methylene in prompt NO formation
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DOI：
10.1016/j.proci.2008.06.175
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
B. A. Williams;J. Sutton;J. W. Fleming
中科院分区：
文献类型：
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作者：
B. A. Williams;J. Sutton;J. W. Fleming
通过对几种低气压甲烷-氧气-氮气火焰的实验物种分布和动力学火焰模型的检验，我们讨论了单线态次甲基(1CH2)在瞬时NO生成机制中的可能性。现有的动力学模型假设CH是唯一的快速NO前体，在燃料非常贫乏的条件下，大大低估了NO的生成。我们构建了一条由单重态CH2与分子氮在火焰早期重新结合生成重氮甲烷CH2NN的动力学路径。尽管大多数重氮甲烷预计会与火焰自由基反应生成氮气，但有一小部分(约10%)会通过NN键的断裂反应生成NO。这导致了对稀薄、低压火焰中NO生成的实验测量的准确预测。假设CH2反应的动力学参数合理，贫氧条件下大量低估NO的情况可以通过在动力学机制中包含1CH2提示的NO途径来纠正。
We address the plausibility of singlet methylene (1CH2) in the prompt NO formation mechanism via examination of experimental species profiles and kinetic flame modeling of several low-pressure methane–oxygen–nitrogen flames. Existing kinetic models assuming CH as the only prompt NO precursor greatly underpredict NO formation under very fuel-lean conditions. We have constructed a kinetic pathway initiated by the recombination of singlet CH2with molecular nitrogen to form diazomethane, CH2NN, early in the flame. Although the majority of the diazomethane is predicted to react with flame radicals to regenerate N2, a small percentage (approximately 10%) is predicted to react via cleavage of the NN bond leading to NO formation. This leads to accurate prediction of the experimental measurements of NO formation in lean, low-pressure flames. Assuming reasonable kinetic parameters for the reactions of CH2, the large underprediction of NO under lean conditions can be rectified by the inclusion of the1CH2prompt NO pathway in the kinetic mechanism.