氧体积分数对乙烯扩散火焰中烟黑生成影响的实验

摘要

In order to evaluate the effect of oxygen concentration on soot formatting and agglomerating in oxygen-lean and-rich C2H4/ O2/ N2 diffusion flame, the diameter of individual particle and mean size of soot agglomerates sampled by thermophoretic method were estimated from transmission electron microscopy (TEM) images. The volume fraction profiles along vertical and radial directions were measured by laser extinction method. Results show that, for diffusion flame, with increased oxygen concentration, soot particle diameter and mean size of agglomerates at the same vertical position will increase and the vertical location of the peak value of soot volume fraction will shift towards flame bottom. The radial distribution of soot volume fraction becomes narrow and peak values near the flame edge increase quickly. For the flame discussed in this paper, soot formation is enhanced with enriched oxygen concentration. The results can be used for small particle pollutants control from combustion.%为了研究氧体积分数对扩散火焰中烟黑颗粒生长和聚合特性的影响,采用热泳沉积取样结合透射电子显微镜(TEM)图像,分析富氧和贫氧环境下乙烯/O2/N2扩散火焰中烟黑颗粒的粒径和颗粒凝聚体平均颗粒数,并采用激光消光法同步测量烟黑颗粒在火焰轴向和径向的体积分数分布.实验结果表明:对于乙烯扩散火焰,氧体积分数的增加,使火焰中心同一高度上的烟黑粒径和凝聚体平均颗粒数增大,进而引起烟黑体积分数增大,峰值位置前移;在火焰径向方向烟黑颗粒分布向中心收缩,边缘位置烟黑体积分数增大.对于本文讨论的扩散火焰,氧体积分数的增加对烟黑的生成具有促进作用,这对于火焰颗粒污染物的控制研究具有参考意义.