层流预混乙烯火焰中碳烟颗粒物的粒径分布

Soot Particle Diameter Distribution in Laminar Premixed Ethylene Flame

通过原位采样方法,使用扫描电迁移率颗粒粒径谱仪(SMPS)对乙烯层流预混合火焰生成的碳烟颗粒物粒径分布进行在线分析.系统地研究了稀释率和采样高度对碳烟颗粒分布的影响规律.结果表明,稀释率太小,将增加小粒径颗粒损失,大粒径颗粒显著增加;稀释率过高,碳烟颗粒易扩散沉积到采样管壁面上,造成损失.在距燃烧器表面不同高度测量碳烟颗粒物分布,发现随着火焰中采样高度增高,成核作用逐渐减弱,凝聚长大作用逐渐增强,颗粒成核与凝聚长大作用之间的相互竞争会影响碳烟颗粒数密度的分布.

Mobility size distribution of soot particles produced from a laminar premixed ethylene flame was obtained by online analysis using scanning mobility particle sizer （SMPS） and through site probe sampling. Soot particle for- mation in flame was obtained Influence of dilution ratio and sampling height on soot particle diameter distribution was studied systematically. The result shows that decreased dilution ratio would increase the loss of small particles, which would form into large particles; while with higher dilution ratio, particles tend to diffuse onto the wall of the sampling tube. Particle diameter distribution was measured at different height, which shows that nucleation gradually decreases while coalition increases with the increasing height. The competition between nucleation and coalition will affect soot particle diameter distribution.