摘要
基于正庚烷层流扩散火焰实验系统,结合热电偶测温技术、比色法测温技术、探针采样技术、发动机排气颗粒物粒径谱仪以及热重分析系统,研究了氢气添加量对碳烟体积分数分布、碳烟颗粒数密度、粒径分布以及氧化活性的影响规律.研究结果表明,由于添加量较低,氢气添加量对火焰温度的影响不明显;正庚烷扩散火焰中碳烟体积分数分布呈现中心高边缘低的规律,氢气的加入没有改变碳烟体积分数的分布特性,但降低了碳烟体积分数峰值,同时还降低了碳烟颗粒数密度峰值,并显著减小了碳烟颗粒粒径,表明氢气的加入可以抑制正庚烷扩散火焰中的碳烟生成;氢气的加入强化了火焰中碳烟的氧化,因此提高了被取样碳烟进一步氧化反应的活化能,降低了被取样碳烟的氧化活性.
The effects of hydrogen addition on the distribution of soot volume fraction,soot particle number concentration,soot particle size distribution and soot oxidative reactivity were studied in n-heptane diffusion flames,coupled with thermocouple pyrometry,the system of color ratio pyrometry,the system of probe sampling,the engine exhaust particle size spectrometer and thermogravimetric analysis.The experimental results show that hydrogen addition has no significant effect on flame temperature due to low addition.The soot volume fraction in the flame center is higher than that at the flame edge.The hydrogen addition has indistinctive effect on the distribution of peak soot volume fraction,but it significantly decreases the peak value of soot volume fraction and the peak particle number concentration.Such results indicate that hydrogen addition can suppress the soot formation in the nheptane flames.The hydrogen addition enhances the oxidation of soot.As a result,sampled soot with high apparent activation energy of further oxidation reaction is formed with hydrogen addition,suggesting a transformation of sampled soot toward lower oxidative reactivity.
作者
刘春雨
张伟
吕刚
王庚源
宋崇林
Liu Chunyu;Zhang Wei;LüGang;Wang Gengyuan;Song Chonglin(State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China)
出处
《燃烧科学与技术》
CAS
CSCD
北大核心
2023年第2期135-142,共8页
Journal of Combustion Science and Technology
基金
国家自然科学基金资助项目(91741127,51921004)
天津市自然科学基金重点资助项目(19JCZDJC40100)。
关键词
正庚烷
扩散火焰
氢气
碳烟体积分数
颗粒数密度
氧化活性
n-heptane
diffusion flame
hydrogen
soot volume fraction
soot number concentration
oxidative reactivity
