有限空间金属纤维表面低氮燃烧特性研究OA

Metal fiber surface combustion technology has become one of the most promising low nitrogen combus-tion technologies for gas boilers because of its advantages of stable combustion process and uniform temperature dis-tribution.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 NOx and thermal NOx on metal fiber surface.The results show that under different excess air coefficients,the generation rate of prompt NOx is faster than that of thermal NOx.However,limited by the effective reaction space and reaction duration,the volume occupied by prompt NOx in the furnace is much smaller than that of thermal NOx.With the increase of excess air coefficient,the generation rate and emission of thermal NOx gradually decrease.When α=1.6,the emission of NOx from flue gas outlet is 22.55 mg/m3,which meets the stan-dard of low nitrogen combustion.Therefore,in addition to changing the flame temperature,oxygen concentration and combustion mode,the generation of thermal NOx can be suppressed by controlling the excessive air coefficient,and ultra-low nitrogen combustion of industrial gas boilers can also be effectively achieved.