过量空气系数对WNS型燃气锅炉混空轻烃燃烧特性的影响

Effect of excess air coefficient on combustion characteristics of air-light hydrocarbon mixing gas in WNS type gas boiler

为研究混空轻烃在O_(2)/N_(2)氛围下燃烧时,过量空气系数对WNS型燃气锅炉燃烧室内的温度分布和NO_(x)生成的影响,利用CFD软件,采用标准k-ε湍流模型、P-1辐射模型和涡耗散燃烧模型进行数值模拟。结果表明:过量空气系数α从1.0增大到1.3的过程中,火焰长度逐渐变短,燃烧室壁面两侧的高温区域逐渐向燃烧器入口端移动,燃烧室的温度场更加均匀,降低了高温区域,进而抑制了Thermal NO_(x)的产生。燃烧室出口处NO_(x)的浓度随着α的增大而逐渐减小,增大α可以有效地降低NO_(x)的排放量。

In order to study the effects of excess air coefficient on temperature distribution and flue gas composition of WNS gas boiler when mixed air light hydrocarbons are burned in O_(2)/N_(2)atmosphere,the standard k-εturbulence model,P-1 radiation model and vortex dissipation combustion model were used by CFD software for numerical simulation.The results show that during the increase of excess air coefficientαfrom 1.0 to 1.3,the flame length gradually becomes shorter,the high temperature area on both sides of the combustion chamber wall gradually moves to the inlet end of the burner,the temperature field is more uniform,the high temperature area is reduced,and the generation of Thermal NO_(x)is inhibited.The concentration of NO_(x)at the outlet of the combustion chamber gradually decreases with the increase ofα,and increasing theαcan effectively reduce the emission of NO_(x).