Experimental and modeling study on the influences of methanol on premixed fuel-rich n-heptane flames
Experimental and modeling study on the influences of methanol on premixed fuel-rich n-heptane flames
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DOI：
10.1016/j.fuel.2012.07.032
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发表时间：
2013
期刊：
影响因子：
7.4
通讯作者：
Gen Chen;Wu Yu;Xue Jiang;Zuo-hua Huang;Zhandong Wang;Zhanjun Cheng
中科院分区：
文献类型：
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作者：
Gen Chen;Wu Yu;Xue Jiang;Zuo-hua Huang;Zhandong Wang;Zhanjun Cheng
正庚烷/O2/Ar两种层流预混火焰的结构（F1.60：λ =1.60，C/O=0.51，和F1.80：λ =1.80，C/O=0.57）和一个层流预混正庚烷/甲醇/O2/Ar火焰（F_（1.80）M：F_（1.80）=1.80，C/O=0.51）在低压（4000 Pa）下用同步辐射光电离和分子束取样质谱（PI-MBMS）技术进行了研究。计算进行了修改的化学机制，令人满意地模拟测试火焰。结果表明，随着当量比的增大，最高火焰温度降低，火焰前锋远离燃烧器表面。F1.80M燃烧后CO浓度低于F1.80燃烧后CO浓度，这不仅与入口碳通量的不同有关，也与CO生成途径的不同有关。随着甲醇的加入，C2-C7烃类中间产物的峰浓度显著降低，且在C/O比不变的情况下降低的幅度小于当量比不变的情况。甲醇的加入促进了甲醛的产生。反应通量分析表明，炔丙基自由基（C_3H_3）的自复合以及C_3H_3与烯丙基自由基（a-C_3 H_5）的交叉反应是所有火焰中小分子化合物生成苯的主要途径.
The structures of two laminar premixed n-heptane/O2/Ar flames (F1.60: Ф=1.60, C/O=0.51, and F1.80: Ф=1.80, C/O=0.57) and one laminar premixed n-heptane/methanol/O2/Ar flame (F1.80M: Ф=1.80, C/O=0.51) are studied at low pressure (4000Pa) by using synchrotron photoionization and molecular-beam sampling-mass spectrometry (PI-MBMS) techniques. Calculations are performed with a modified chemical mechanism, which satisfactorily simulates the tested flames. The results show that as equivalence ratio increases, the maximum flame temperature is reduced and the flame front is shifted away from the burner surface. The post-flame CO concentration in F1.80M is lower than that in F1.80, which is attributed not only to the difference in inlet carbon flux but also to the variation in CO formation pathway. As methanol is added, the peak concentrations of C2–C7hydrocarbon intermediates are reduced substantially, and the extent of the reduction in the case of constant C/O ratio is smaller than that in the case of constant equivalence ratio. The production of formaldehyde is promoted with the addition of methanol. Reaction flux analysis indicates that the self-recombination of propargyl radical (C3H3) and the cross reaction between C3H3and allyl radical (a-C3H5) are the dominant pathways leading from small aliphatics to benzene for all the flames.