This study investigated the effect of CO/H₂/N₂ addition on the morphological evolutions and nanostructures of soot generated from a laminar co-flow ethylene diffusion flame through utilizing the method of thermophoretic sampling and transmission electron microscopy (TEM). The additions were introduced into the inner tube along with the fuel stream, and the volume fractions of the additions are 10%, 20% and 30%. Specifically, the parameters of soot production, primary particle diameter (D_p), fractal dimension (D_f), fractal pre-factor (k_g) and the nanostructures were determined and analyzed. A reduction in soot production was observed with increasing proportion of the additives, demonstrating the addition of these diluent gases could inhibit the soot formation. Among the three additives, N₂ is the most effective in reducing soot yield. The size analysis of soot particles and aggregates indicated the addition of CO or N₂ could diminish the primary particle diameter and fractal parameters. The addition of H₂ could reduce the primary particle diameter at the bottom flame while yields greater primary particles at 40 mm HAB. This result demonstrated that H₂ addition may weaken the oxidation occurring on soot particles. High resolution transmission electron microscopy (HRTEM) analysis was also developed and the results showed that the addition of CO or H₂ results in greater fringe length, smaller fringe tortuosity and inter-fringe spacing for soot particles, demonstrating the more orderly and compact lattice structure. In particular, the nanostructure parameters of soot particles in H₂ enriched flame vary more significantly than those in CO enriched flame, demonstrating the soot nanostructure is more graphitized in H₂ enriched flame. Different from the case of CO or H₂ addition, the lattice characteristics for soot in the flames with N₂ addition present inverse variation tendency.

本研究利用热泳取样和透射电子显微镜（TEM）方法研究了CO / H ₂ / N _2的添加对层流共流乙烯扩散火焰产生的烟灰的形态演变和纳米结构的影响。将添加物与燃料流一起引入内管，添加物的体积分数为10％，20％和30％。具体而言，烟灰产生，初始粒径（D _p），分形维数（D _f），分形因数（k _{g）的参数}）并确定并分析了纳米结构。随着添加剂比例的增加，观察到烟灰产生量减少，这表明添加这些稀释气体可以抑制烟灰的形成。在这三种添加剂中，N ₂是降低烟灰收率最有效的添加剂。烟尘颗粒和聚集体的尺寸分析表明，添加CO或N ₂可以减小一次粒径和分形参数。H _2的添加可以减小底部火焰处的一次粒径，而在40 mm HAB处产生更大的一次粒径。该结果表明H ₂加入可能会削弱烟灰颗粒上发生的氧化。还开发了高分辨率透射电子显微镜（HRTEM）分析，结果表明，添加CO或H _2会导致烟尘颗粒的条纹长度更大，条纹曲折性和条纹间距减小，表明晶格结构更加有序和紧凑。尤其是，富H ₂火焰中烟灰颗粒的纳米结构参数变化比富CO火焰中烟尘颗粒的纳米结构参数变化更大，这表明烟尘纳米结构在富H ₂火焰中石墨化程度更高。与添加CO或H ₂的情况不同，带有N ₂的火焰中烟灰的晶格特性 加法呈现逆变化趋势。