金属纤维表面燃烧技术因其燃烧过程稳定、温度分布均匀等优势，成为目前燃气锅炉最具发展前景的低氮燃烧技术之一。基于有限空间金属纤维表面低氮燃烧实验数据，建立了三维金属纤维表面燃烧物理模型，并基于多孔介质阻力模型、金属纤维湍流模型、EDC燃烧模型进行了全预混燃烧数值求解，获得了有限空间金属纤维表面燃烧的火焰燃烧情况、热态烟气流场速度特性、炉膛内的温度场分布和燃料分布。考虑了不同过量空气系数的影响，得到了金属纤维表面燃烧快速型NO _x 和热力型NO _x 排放特性和平均生成速率分布规律。结果表明：不同过量空气系数下，快速型NO _x 比热力型NO _x 的生成速率更快，但受限于有效反应空间和反应持续时间，快速型NO _x 在炉膛中所占体积远小于热力型NO _x；随着过量空气系数增大，热力型NO _x 的生成速率和排放浓度都逐渐减小，当过量空气系数α=1.6时，烟气出口的NO _x 排放浓度为22.55 mg/m³，满足低氮燃烧的标准。因此，除改变火焰温度、氧气浓度和燃烧方式，通过控制过量空气系数来抑制热力型NO _x 生成，可有效实现工业燃气锅炉超低氮燃烧。

Metal fiber surface combustion technology has become one of the most promising low nitrogen combustion technologies for gas boilers because of its advantages of stable combustion process and uniform temperature distribution. Based on the low-nitrogen combustion experimental data of metal fiber surface in limited space, this study established a three-dimensional physical model of metal fiber surface combustion and carried out the full-premixed combustion numerical solution based on the porous medium resistance model, metal fiber turbulence model and EDC combustion model. It obtained the flame combustion conditions and the velocity characteristics of hot smoke flow field of metal fiber surface combustion in limited space, as well as the temperature field distribution and fuel distribution in furnace. Considering the influence of different excess air coefficient, it studied the emission characte-ristics and average generation rate distribution of prompt NO _x and thermal NO _x on metal fiber surface. The results show that under different excess air coefficients, the generation rate of prompt NO _x is faster than that of thermal NO _x . However, limited by the effective reaction space and reaction duration, the volume occupied by prompt NO _x in the furnace is much smaller than that of thermal NO _x .With the increase of excess air coefficient, the generation rate and emission of thermal NO _x gradually decrease. When α=1.6, the emission of NO _x from flue gas outlet is 22.55 mg/m³, which meets the standard of low nitrogen combustion. Therefore, in addition to changing the flame temperature, oxygen concentration and combustion mode, the generation of thermal NO _x can be suppressed by controlling the excessive air coefficient, and ultra-low nitrogen combustion of industrial gas boilers can also be effectively achieved.