以氨气、乙烯和氩气同向射流扩散火焰为研究对象,采用消光法、快速插入测温法结合CHEMKIN模拟,研究了不同体积分数(0%,10%,20%和30%)氨气与乙烯混合燃烧后火焰中碳烟体积分数分布、中心线温度分布以及氨气热效应和化学效应对碳烟生成的影响。结果表明:随着NH3掺混比增大,碳烟的最大体积分数减小,碳烟生成区域向火焰中心线与火焰下游移动;随着NH3掺混比增大,火焰最高温度增大;CHEMKIN模拟中采用NH3-C2H4-PAH燃烧机理和脱氢加乙炔(HACA)碳烟生长机理,运用虚拟氨气(FNH3)得到了NH3的热效应与化学效应对碳烟生成的影响,模拟结果表明,随着NH3掺混比增加,碳烟的最大体积分数减小;氨气热效应对碳烟的抑制作用在NH3体积分数分别为0%,10%,20%,30%时几乎呈现线性变化,而化学效应在NH3体积分数小于10%时能显著抑制碳烟生成,当继续增大NH3掺混比,氨气化学效应对碳烟的抑制作用逐渐减小;NH3的掺混使得多环芳烃(PAHs),H,C2H2,C3H3的浓度降低和CN的浓度升高,抑制了碳烟前驱物的形成,模拟结果也表明,NH3的化学效应对升高火焰温度、降低PAHs摩尔分数和碳烟体积分数发挥重要作用,而热效应在抑制C2H2和C3H3的生成过程中作用更加明显。

In this paper,the co-flow diffusion flame of ammonia,ethylene and argon was investigated. The extinction light method, rapid insertion temperature measurement method combined with CHEMKIN simulation were used to study the volume fraction of soot distribu-tion, centerline temperature distribution, and the influence of ammonia thermal and chemical effects on soot formation in the ethylene flame blended with different volume fractions of ammo-nia (0%, 10%, 20% and 30%). The experimental results show that the maximum volume frac-tion of soot decreases, the maximum flame temperature increases and the soot formation area moves towards the flame centerline and downstream of the flame as the NH3 mixing ratio increa-ses. The NH3-C2H4-PAH mechanism and hydrogen abstraction acetylene addition (HACA) soot growth mechanism were used in the CHEMKIN simulations, and the thermal and chemical effects of NH3 on soot formation were obtained by introducing the fictitious ammonia (FNH3). The simulation results show that the maximum volume fraction of soot decreases with the in-crease of ammonia ratio. The inhibition of soot formation by the thermal effect of NH3 varies al-most linearly from 0%, 10%, 20%, 30% NH3 blending. The chemical effect can significantly in-hibit soot formation when the ammonia blending ratio is less than 10%, and the inhibition of soot formation by the chemical effect of ammonia gradually decreases when the ammonia blending ratio continues to increase. The mixing of NH3 results in the reduction of the concentration of polycy-clic aromatic hydrocarbons (PAHs), H, C2H2, and C3H3, and the increase of the concentration of CN, which inhibits the formation of soot precursors. The simulation results also indicate that the chemical effect of NH3 plays a more important role in raising the flame temperature and re-ducing the mole fraction of PAHs and the volume fraction of soot, while the thermal effect plays a more obvious role in inhibiting the formation of C2H2 and C3H3.