The quenching distance of premixed hydrocarbon flames is of significant importance for studying flame/wall interactions and for understanding the unburned hydrocarbon emissions of internal combustion engines. Motivated by the fact that the standoff distance of premixed burner-stabilized flames could be used to investigate the behavior of head-on quenching distance of freely propagating flames despite the different physics involved, a parametric investigation on the standoff distances of methane, ethane, and propane burner-stabilized flames was conducted numerically using a detailed chemical kinetic mechanism, with a focus on the effects of hydrogen addition. Specifically, the minimum standoff distance was found to quantitatively correlate with the head-on quenching distance of premixed flames. The variations of the minimum standoff distance as a function of hydrogen fractions were then investigated in detail. The results showed that as hydrogen fraction increased, the minimum standoff distances decreased monotonously for all the hydrocarbon/air flames, with the reduction being most significant for methane fuel. Accompanying kinetic analysis showed that hydrogen addition enhances the heat release process, which promotes the reduction of minimum standoff distance. Subsequently, the dependences of the minimum standoff distance on fuel dilution, equivalence ratios, unburned gas temperatures, and pressures were explored. In addition, the potential to study the parametric dependence on unburned hydrocarbons emissions induced by near-wall flame quenching using the burner-stabilized flame model was discussed. The current study provides a useful approach to quantify the quenching distance of premixed flames, which has practical applications in internal combustion engines. Moreover, the dependence of standoff distance on hydrogen addition and other varying flame parameters can now be more fundamentally understood with the help of detailed chemical kinetics.

中文翻译：

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加氢对各种烃类燃料预混合燃烧器稳定火焰对峙距离的影响

预混碳氢化合物火焰的淬火距离对于研究火焰/壁之间的相互作用以及理解内燃机的未燃烧碳氢化合物排放具有非常重要的意义。受以下事实激励：预混合燃烧器稳定火焰的间隔距离可用于研究自由传播的火焰的正向淬火距离的行为，尽管所涉及的物理原理不同，但甲烷，乙烷和甲烷的间隔距离的参数化研究使用详细的化学动力学机理对丙烷燃烧器稳定的火焰进行了数值模拟，重点是加氢的影响。具体而言，发现最小隔离距离与预混火焰的迎头淬火距离在数量上相关。然后详细研究了最小间隔距离随氢分数的变化。结果表明，随着氢分数的增加，所有碳氢化合物/空气火焰的最小对峙距离单调减小，其中甲烷燃料的减小最显着。伴随的动力学分析表明，氢的加入促进了放热过程，从而促进了最小间隔距离的减小。随后，研究了最小间隔距离对燃料稀释度，当量比，未燃烧气体温度和压力的依赖性。此外，讨论了使用燃烧器稳定火焰模型研究由近壁火焰淬火引起的对未燃烧碳氢化合物排放的参数依赖性的潜力。当前的研究提供了一种有用的方法来量化预混火焰的熄灭距离，该方法在内燃机中具有实际应用。而且，借助详细的化学动力学，现在可以从根本上理解对峙距离对氢的添加和其他变化的火焰参数的依赖性。