Study on sooting behavior of premixed C1-C4 n-alkanes/air flames using a micro flow reactor with a controlled temperature profile
Study on sooting behavior of premixed C1-C4 n-alkanes/air flames using a micro flow reactor with a controlled temperature profile
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DOI：
10.1016/j.combustflame.2016.09.007
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发表时间：
2016-12-01
影响因子：
4.4
通讯作者：
Maruta, Kaoru
中科院分区：
文献类型：
--
作者：
Dubey, Ajit Kumar;Tezuka, Takuya;Maruta, Kaoru
利用具有受控温度分布的微流动反应器，对预混的C-1-C-4正构烷烃混合物在最高温度低于1400K时的结灰行为进行了实验研究。观察到所有混合物的火焰和烟尘对当量比(1.5-4.0)的响应。观测到的甲烷、丙烷和正丁烷的临界烟尘当量比为1.8，而乙烷的临界烟尘当量比为1.9。在相似临界当量下，通过观察积灰区域上游边缘的相对轴向位置，进一步定性地解释了积灰行为，其中相对下游的位置表示延迟了碳烟的形成。当量比为1.8时，碳烟上游沿轴向位置的顺序为：丙烷<；正丁烷<；甲烷；当量比为1.9时，碳烟上游沿轴向位置的顺序为：丙烷与正丁烷相似，乙烷与甲烷相似。随着当量比的增加，乙烷、丙烷和正丁烷的烟尘区域向上游移动。而甲烷当量比在2.0以上时变化不大。对观测到的火焰和烟尘响应进行了详细的化学一维计算。乙烷被发现是最活跃的燃料，因为从燃料中提取氢和在火焰中产生氢的耦合。计算的火焰位置在甲烷的不同机理中差别很大。对于所有的反应机理和所有的燃料，在火焰中最大的放热反应是CH3+CH3=C2H6。使用KAUST机制对所有当量比在1.35-4.0范围内的燃料进行了计算，以讨论总体碳烟行为。最大计算的芘摩尔分数被用来定性地研究相对碳烟行为，因为它们与碳烟有很好的相关性。最大计算的Py摩尔分数的趋势定性地解释了在当前实验中观察到的燃料的临界烟尘当量比和总体烟尘行为的趋势。(C)2016年，燃烧研究所。爱思唯尔公司出版，版权所有。
Sooting behavior of premixed C-1-C-4 n-alkanesiair mixtures at maximum temperatures lower than 1400 K is studied experimentally using a micro flow reactor with a controlled temperature profile. Flame and soot responses to equivalence ratio (1.5-4.0) are observed for all mixtures. Critical sooting equivalence ratio observed for methane, propane and n-butane is 1.8, whereas, for ethane it is 1.9. Sooting behavior at similar critical equivalence is further interpreted qualitatively by observing relative axial locations of upstream edges of sooting region, where relative downstream location indicates delayed soot formation. The order of axial location of upstream edge of soot at equivalence ratio 1.8 is: propane < n-butane < methane; and, the order at equivalence ratio 1.9 is: propane similar to n-butane similar to ethane < methane. Sooting region shifts upstream for ethane, propane and n-butane with increasing equivalence ratio. However, it does not change for methane with increasing equivalence ratio above 2.0. One dimensional computations with detailed chemistry are performed to study observed flame and soot responses. Ethane is found to be most reactive fuel due to coupling of H abstraction from fuel and H production in the flame. Computed flame positions vary widely among mechanisms for methane. Most exothermic reaction at flame is CH3+CH3=C2H6 for all mechanisms and for all the fuels. Computations using KAUST mechanism are performed for all the fuels at various equivalence ratios in the range 1.35-4.0 to discuss overall sooting behavior. Maximum computed pyrene mole fractions are used to study relative sooting behavior qualitatively as they correlate well with soot. The trends of maximum computed pyrene mole fractions qualitatively explain observed trends of critical sooting equivalence ratios and overall sooting behavior of fuels in the current experiments. (C) 2016 The Combustion Institute. Published by Elsevier Inc. All rights reserved.