Experimental investigation on the effects of hydrogen addition on thermal characteristics of methane/air premixed flames
Experimental investigation on the effects of hydrogen addition on thermal characteristics of methane/air premixed flames
复制标题
加氢对甲烷/空气预混火焰热特性影响的实验研究
DOI：
10.1016/j.fuel.2013.07.024
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发表时间：
2014-01-01
期刊：
影响因子：
7.4
通讯作者：
Wei, S.
中科院分区：
文献类型：
--
作者：
Hu, G.;Zhang, S.;Wei, S.
本文介绍了加氢和不加氢两种情况下甲烷/空气层流预混火焰测量的实验研究。预混火焰在常压下稳定在麦肯纳平焰燃烧器上。采用移动热电偶法测量了当量比和富氢率范围内的轴向火焰温度分布。通过求解应用于平面火焰的质量、能量和组分的连续性方程，对测量的温度进行了分析，并考虑辐射损失进行了修正，以估计火焰的热释放速率。提出了一些重要的火焰性质，如峰值温度、平均温度、火焰厚度、反应区厚度和燃烧效率，以表征氢的富集度对层流火焰传播的影响。结果表明，层流火焰中氢的存在对火焰反应有一定的促进作用。随着燃料中氢添加分数的增加，放热峰值速率和燃烧效率增加，平均温度降低。对放热曲线的分析表明，氢气的加入对火焰放热曲线的早期部分有显著影响。氢气强化的火焰在对数放热率与火焰温度倒数的曲线图上呈线性近似。基于测得的一维预混火焰的温度分布，利用GRI-Mech 3.0详细的动力学反应机理，对一维层流稳定火焰进行了数值模拟。然后对每个反应的放热情况进行了分析。结果表明，随着氢气浓度的增加，OH+H-2H+H2O反应对早期放热的贡献逐渐增大，这是由于氢气加成导致火焰中H自由基浓度增加所致。促进氢的生成加快了火焰的燃烧速度，使火焰和反应区的厚度大大变薄。(C)2013爱思唯尔有限公司。保留所有权利。
This paper presented an experimental study on the measurements of premixed laminar methane/air flames with and without hydrogen addition. The premixed flames were stabilized on a McKenna flat fame burner at atmospheric pressure. The traveling thermocouple approach was used to measure the axial flame temperature profiles over ranges of equivalence ratios and hydrogen enriching ratios. The measured temperatures, corrected by considering radiation loss, were analyzed to estimate the rate of flame heat release, by solving the continuity equations of mass, energy, and species which were applied to a flat flame. Some of important flame properties, such as the peak temperature, the average temperature, the flame thickness, the thickness of reaction zone and combustion efficiency, were presented to characterize the effect of hydrogen enrichment on laminar flame propagation. It is shown that the presence of hydrogen in laminar flame can promote flame reaction to some extent. With an increase of hydrogen addition fraction in fuel, the peak rate of heat release and combustion efficiency show increases, while the average temperature gives decrease. The analysis of the heat release profiles suggested that hydrogen addition has significant effect on the early part of flame heat release profile. The flames enriched by hydrogen show linear approximations in the plots of the logarithmic heat release rate against the reciprocal of flame temperature. A modeling for one dimensional premixed laminar burner-stabilized flame had been implemented with GRI-Mech 3.0 detailed kinetic reaction mechanism, based on the measured temperature profiles of these premixed flames. And then an analysis on the heat release was performed for each reaction. It suggested that the reaction OH + H-2 H + H2O gradually increases its contribution to the early heat release with the increase of hydrogen enrichment, which is due to the fact of hydrogen addition resulting in an increased concentration of radical H in flame. The promoted H formation accelerates the flame burning velocity, and then thins the thicknesses of flame and reaction zone to a great extent. (C) 2013 Elsevier Ltd. All rights reserved.