CO2/N2稀释对H2/CH4层流火焰传播特性的影响

利用本生灯-纹影系统实验研究含有CO₂，N₂的掺氢天然气层流预混火焰传播速度，并应用GRI-3.0机理模拟计算不同组分预混燃气绝热火焰温度、敏感性系数及重要自由基浓度等，详细讨论CO₂，N₂的稀释效应.研究表明，GRI-3.0机理能较好地预测掺氢天然气层流预混火焰传播速度；CO₂，N₂稀释组分会显著抑制掺氢天然气层流预混火焰速度及其绝热火焰温度；与N₂相比，CO₂不仅具有较强的热力学效应，且随着CO₂稀释比的增加，火焰中重要自由基H浓度显著减少，抑制氧化反应H+O₂O+OH对燃烧的主导促进效应，使预混燃料的层流火焰传播速度显著降低.

Effect of CO2/N2 Dilution on the Propagation of Laminar Flames of H2/CH4

The transmission speeds of laminar flames of H₂/CH₄/air mixtures with CO₂/N₂ dilution were experimentally studied using the Bunsen burner method incorporating the schlieren technique. To thoroughly investigate the diluted effect of CO₂/N₂ on laminar premixed flames of H₂/CH₄/air mixtures， the adiabatic flame temperatures， sensitivities of the mixtures with various CO₂/N₂ dilution ratios and the mole fractions of vital radicals were calculated using GRI-3.0 mechanism. The research results showed that GRI-3.0 mechanism provided better estimates of the transmission speeds of hythane flames; laminar flame speeds and adiabatic flame temperatures decreased with the growth of CO₂/N₂ dilution ratios. Compared with N₂， CO₂ presented the stronger thermal effect and chemical kinetics effect on the decrease of the laminar flame speeds of diluted hythane. With the increase of CO₂ dilution ratios， the dominant promotion of the oxidation reaction H+O₂O+OH on the mass burning rates of mixtures can be inhibited by the significant reductions of H radicals. Therefore， the laminar flame speed of mixtures remarkable decreased with the growth of CO₂ rations.