H_(2)-Air交叉射流火焰燃烧排放特性的数值模拟

Numerical simulation of H_(2)-air cross jet flame combustion and emission characteristics

对H_(2)-Air交叉射流火焰进行了数值模拟研究,考察了燃烧器空气喷嘴距离(L)、角度(α)以及数目(N)对温度场、火焰轮廓和NO_(x)排放的影响,并获得了最低NO_(x)排放性能的燃烧器几何参数配置。结果表明:增大L和α整体上有助于产生更加均匀的温度分布和更低的温度峰值,进而导致更低的NO_(x)排放;增加N将促进燃料和空气的混合,强化燃烧形成中心高温区,进而显著提升NO_(x)的排放,然而高温区随N的增大逐渐被延伸至炉膛出口,导致燃烧效率从99.99%降低至98.99%。在当前的燃烧装置中,最佳的燃烧器参数配置为L=6D、α=40°、N=2,此时H_(2)-Air交叉射流火焰燃烧效率高达99.99%,且最低NO_(x)排放达到5×10^(-6)。

This paper carries out a numerical simulation study on H_(2)-Air cross-jet flame,and the effects of air nozzle distance(L),angle(α)and number(N)on temperature,flame outline and NO_(x)emission are examined,and the optimal burner parameters for the lowest NO_(x)emission has been obtained.The results show that,enlarging L andαis beneficial for producing a more uniform temperature field as well as a lower temperature peak,which further results in a lower NO_(x)emission.Increasing N can enhance the mixing between fuel and air,and form a high temperature region in the central furnace owing to intensified combustion,which leads to increased NO_(x)emission.However,the central high temperature region is gradually stretched to the exit of the furnace with the increase of N,leading to a decrease of combustion efficiency from 99.99%to 98.99%.In the present combustion facility,the optimal burner parameters are L=6D,α=40°and N=2,through which H_(2)-Air cross-jet flame can maintain a high combustion efficiency of 99.99%while producing the lowest NO_(x)emission at 5×10^(-6).