富氧空气/甲烷扩散燃烧的NO抑制机理的数值研究

为了开发适用于富氧燃烧的NO抑制技术,以对向流扩散火焰这一扩散燃烧的典型形态为对象,利用所建立的基元反应动力学模型研究了燃料稀释（CO2为稀释剂）以及速度梯度的改变对富氧空气/甲烷扩散火焰中NO生成的影响.用CO2稀释燃料甲烷得到的计算结果表明,随着燃料中CO2浓度的增大,火焰结构和NO生成的机理发生了显著变化,NO排放指数EINO（Emission index of NO）单调减少.改变速度梯度发现,随着速度梯度的增加,热力型NO质量生成速率以及EINO快速下降.这些研究表明,用CO2稀释燃料以及增加速度梯度可以减少富氧火焰中NO的生成.

A Numerical Study on Reduction Methods of NO in Methane/Oxygen-enriched Air Diffusion Flame

Sincethereduction technology ofNOformation has been a key factor to facilitate oxygen-enriched combustion, reductionmethodsof NO in oxygen-enriched air/methane diffusion flame were studied in this paper. A ounterflow diffusion flame as a basic configuration ofdiffusion flames was studied, and an oxygen-enriched air/methane counterflow diffusion flame was analyzed numerically using detailed chemi-cal kinetic, for conditions that methane stream was diluted with the dilution (CO2 ), the influence of velocity gradient was studied in thesame time. The obtained results show that the flame structure and dominant mechanism of NO formation change greatly with the change ofconcentration of diluents in CO2 , the NO (Emission index of NO) decreased gradually as the concentration of diluents CO2 was increased.The amount of thermal NO generation and the emission index of NO decrease together as the velocity gradient becomes large. Those resultssuggest that fuel diluted by CO2 and the large velocity gradient may reduce the NO formation in the oxygen-enriched combustion.