Kinetic effects of NO addition on n-dodecane cool and warm diffusion flames
Kinetic effects of NO addition on n-dodecane cool and warm diffusion flames
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DOI：
10.1016/j.proci.2020.06.002
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发表时间：
2020-07
期刊：
影响因子：
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通讯作者：
Mengni Zhou;O. Yehia;C. Reuter;Christopher M. Burger;Y. Murakami;Hao Zhao;Y. Ju
中科院分区：
文献类型：
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作者：
Mengni Zhou;O. Yehia;C. Reuter;Christopher M. Burger;Y. Murakami;Hao Zhao;Y. Ju
本文利用逆流燃烧系统研究了NO对正十二烷冷、温扩散火焰动力学特性和燃烧极限的影响。结果表明，NO在冷、温火焰中起着不同的作用，这是由于其反应途径对火焰温度的敏感性不同以及与NO的相互作用。NO的加入降低了冷火焰的熄灭极限，延迟了从温火焰到冷火焰的熄灭转变，促进了从温火焰到热火焰的着火转变。此外，还进行了喷射搅拌反应器（JSR）中的正十二烷氧化实验，以建立和验证正十二烷/NOx动力学模型。反应途径和敏感性分析表明，对于冷火焰，NO的加入抑制了正十二烷的低温氧化，并通过NO+ RO 2 Participate NO2+RO消耗了RO 2，降低了火焰温度，这与继续过氧自由基支化序列的异构化反应竞争。模型预测很好地捕捉到了NO对冷火焰熄灭极限的抑制作用的实验趋势。对于暖火焰，观察到两种不同类型的暖火焰转变，暖火焰熄灭转变为冷火焰和暖火焰重燃转变为热火焰。结果表明，NO的加入抑制了热熄火向冷火焰的转变，而促进了热火焰向热火焰的再点火转变。开发的动力学模型捕捉实验观察到的暖火焰过渡到冷火焰，但未能预测在类似的实验条件下的暖火焰重燃到热火焰。
The kinetic effects of NO addition on the flame dynamics and burning limits ofn-dodecane cool and warm diffusion flames are investigated experimentally and computationally using a counterflow system. The results show that NO plays different roles in cool and warm flames due to their different reaction pathway sensitivities to the flame temperature and interactions with NO. We observe that NO addition decreases the cool flame extinction limit, delays the extinction transition from warm flame to cool flame, and promotes the ignition transition from warm flame to hot flame. In addition, jet-stirred reactor (JSR) experiments ofn-dodecane oxidation with and without NO addition are also performed to develop and validate an-dodecane/NOxkinetic model. Reaction pathway and sensitivity analyses reveal that, for cool flames, NO addition inhibits the low-temperature oxidation ofn-dodecane and reduces the flame temperature due to the consumption of RO2via NO+RO2↔NO2+RO, which competes with the isomerization reaction that continues the peroxy radical branching sequence. The model prediction captures well the experimental trend of the inhibiting effect of NO on the cool flame extinction limit. For warm flames, two different kinds of warm flame transitions, the warm flame extinction transition to cool flame and the warm flame reignition transition to hot flame, were observed. The results suggest that warm extinction transition to cool flame is suppressed by NO addition while the warm flame reignition transition to hot flame is promoted. The kinetic model developed captures well the experimentally observed warm flame transitions to cool flame but fails to predict the warm flame reignition to hot flame at similar experimental conditions.