乙烯预混火焰中燃空当量比对碳烟纳观结构、分形维数和氧化活性的影响  

Effect of Equivalent Ratio on the Nanostructure,Fractal Dimension and Oxidation Activity of Soot Particles from Ethylene Premixed Flame

作　　者：王子晔 刘野[1] 吕刚[1] 宋崇林[1] 毕元 Wang Ziye;Liu Ye;LüGang;Song Chonglin;Bi Yuan(State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学内燃机燃烧学国家重点实验室,天津300072

出　　处：《燃烧科学与技术》2020年第3期280-286,共7页Journal of Combustion Science and Technology

基　　金：国家自然科学基金资助项目(91741127,51876142);天津市科技计划创新平台专项中外联合研究中心建设项目(18PTZWHZ00170).

摘　　要：基于乙烯/氧气预混燃烧系统以及热泳取样和毛细管取样系统,结合场发射透射电子显微镜和热重分析技术,研究了燃空当量比对碳烟颗粒纳观结构、分形维数和氧化活性的影响规律.研究结果表明,随着燃空当量比的增加,碳烟分形维数和基本碳粒子粒径均增加,表明碳烟颗粒团聚程度提高,碳烟生长得到促进;随燃空当量比增加,碳烟微晶长度增大,层间距和曲率均减小,碳烟微观结构更为有序;燃空当量比的增加,导致碳烟的氧化反应特征参数值均增大,碳烟氧化活性减小.另一方面,碳烟的微晶长度、层间距和曲率与表观活化能有较好的线性相关性,即碳烟结构越有序,氧化活性越低.此外,分形维数与表观活化能也存在一定的正相关性.The effect of equivalent ratio on the nanostructure,fractal dimension and oxidation activity of soot particles was studied in this paper.The soot generated from an ethylene/oxygen premixed flame was harvested using thermophoretic sampling and capillary sampling systems,with the combination of field emission transmission electron microscopy and thermogravimetric analysis techniques.Experimental results show that the fractal dimension of soot particles and the size of primary particles increase in response to the increasing equivalent ratio,suggesting an increase in the degree of agglomeration of soot particles and the promoted growth of soot particles.With the increase in equivalent ratio,the length of crystallites of soot particles increases while both the separation distance and tortuosity decrease,indicating that the structure of soot particles becomes more ordered.The increase in equivalence ratio also leads to a decrease in the oxidation activity of soot particles,which is evidenced by the increased characteristic parameters of soot oxidation reaction.In addition,there are good linear relationships between the crystallite length,separation distance,tortuosity and the apparent activation energy.In other words,the soot particles with more ordered structure have a lower oxidation reactivity.There is also a certain positive correlation between fractal dimension and apparent activation energy.

关 键 词：碳烟 燃空当量比 分形维数 纳观结构 氧化活性 

分 类 号：TF055[冶金工程—冶金物理化学]