基于反扩散燃烧的 $ CH_{4} $ 燃烧特性及 $ NO_{x} $ 排放的数值研究

反扩散燃烧具有火焰温度均匀、污染物排放低的特点。针对基于反扩散燃烧的天然气低氮氧化物 $ \left(NO_{x}\right) $燃烧器，文章利用CFD软件对燃烧器反扩散燃烧的燃烧特性进行数值研究，分析分级燃烧过程及热力型和快速型 $ NO_{x} $的生成特点，提出“气包风”的反扩散燃烧组织思想；研究不同过量空气系数、烟气再循环率对流场分布、温度场分布、 $ NO_{x} $排放特性的影响。研究结果表明：随着过量空气系数增大，火焰长度变短，燃烧速率变快，燃烧状况得到改善， $ NO_{x} $排放呈现先增加后减少的变化趋势；随着烟气再循环率的增加，炉膛内火焰平均温度与出口处 $ NO_{x} $排放均呈下降趋势，当烟气再循环率为0.20时，出口处 $ NO_{x} $排放降低约95%，实现超低排放。该研究对反扩散火焰在工业生产中的应用具有一定的指导意义。

Anti-diffusion combustion has the characteristics of uniform flame temperature and low pollutant emission. Aiming at the natural gas low $ NO_{x} $ burner based on anti-diffusion combustion, the combustion characteristics of anti-diffusion combustion of the burner are numerically studied by CFD software, the staged combustion process and the generation characteristics of thermal and rapid $ NO_{x} $ are analyzed, and the anti-diffusion combustion organization idea of "air bag wind" is put forward. The effects of different excess air coefficient and flue gas recirculation rate on flow field distribution, temperature field distribution and $ NO_{x} $ emission characteristics are studied. The results show that with the increase of excess air coefficient, the flame length becomes shorter, the combustion rate becomes faster, the combustion condition is improved, and the $ NO_{x} $ emission increases first and then decreases. With the increase of the flue gas recirculation rate, the average flame temperature in the furnace and the $ NO_{x} $ emission at the outlet both show a downward trend. When the flue gas recirculation rate is 0.20, the $ NO_{x} $ emission at the outlet decreases by about 95%, achieving ultra-low emission, which has guiding significance for the application of anti-diffusion flame in industrial production.