N2和CO2稀释对CH4/O2扩散火焰反应区和结构特性的影响  

Effects of N2/CO2 on the Reaction Zone and Structure Characteristics of the CH4/O2 Diffusion Flame

作　　者：杨家宝 何磊[1] 祝慧雯 郭庆华[1] 龚岩[1] 于广锁[1,2] YANG Jiabao;HE Lei;ZHU Huiwen;GUO Qinghua;GONG Yan;YU Guangsuo(Key Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education,East China University of Science and Technology,Shanghai 200237,China;State Key Laboratory of High-Efficiency Coal Utilization and Green Chemical Engineering,Ningxia University,Yinchuan 750021,China)

机构地区：[1]华东理工大学煤气化及能源化工教育部重点实验室,上海200237 [2]宁夏大学省部共建煤炭高效利用与绿色化工国家重点实验室,银川750021

出　　处：《华东理工大学学报（自然科学版）》2019年第6期853-859,共7页Journal of East China University of Science and Technology

基　　金：国家重点研发计划（2017YFB0602404）;国家自然科学基金项目（21676091）

摘　　要：利用紫外成像系统获得了CH4/O2同轴射流扩散火焰的OH*二维辐射分布,并对其进行了Abel逆变换处理。基于OH*分布特性的变化,重点探究了氧化剂中N2和CO2体积分数对火焰反应区和结构特性的影响,并进一步比较了两种稀释火焰反应区和结构特性的区别。结果表明:随稀释剂体积分数增加,火焰更加细长。在稀释剂体积分数相同的条件下,CO2稀释时火焰具有更为狭窄的火焰锋面,且OH*辐射强度显著低于N2稀释火焰。稀释剂体积分数的增加使OH*的生成机理发生改变,从而导致火焰的核心反应区发生位移。火焰反应区的轴向高度随稀释剂体积分数的增加呈先增大后减小的变化趋势。与N2稀释火焰相比,反应机理转变对CO2稀释火焰反应区轴向高度的影响更大。Based on the experimental platform of diffusion flame, the two-dimensional OH* distribution in the methane/oxygen co-flow diffusion flames was obtained by a UV imaging system, and a Abel deconvolution algorithm was performed as well. According to the variation of the distribution characteristics of OH*, the effects of the contents of N2 and CO2 on the flame reaction zone and structural characteristics were investigated. Additionally, the differences in the flame reaction zone and structural characteristics between the N2 diluted flame and the CO2 diluted flame were further compared. The results show that the flame turns to be thinner with increase in the diluent content. The CO2 diluted flame presents a narrower flame front than that of the N2 diluted flame under the same conditions, and the OH*chemiluminescence intensity is significantly lower. When more dilution is added into oxidant, the position of the OH*peak intensity slightly move toward flame downstream, until the dilution content reaches a certain critical value.Afterwards, it suddenly moves to the region near the outlet of the nozzle and finally tends to a constant. The increase in the diluent content in the oxidant leads to the change of dominant reaction for the OH* formation, resulting in a displacement of the flame core reaction zone. With the increase in the diluent content, the axial height of the flame reaction zone does not increase continuously, in contrast, it starts to decrease upon increasing to a certain range.Compared with the N2 diluted flame, the reaction mechanism transformation has more impacts on the axial height of the flame reaction zone in the CO2 diluted flame.

关 键 词：OH~*辐射 扩散火焰 N2稀释火焰 CO2稀释火焰 火焰结构 

分 类 号：O433.52[机械工程—光学工程]