直流电场对甲烷−氧气扩散火焰中OH^(*)辐射发光特性的影响  

Effect of direct current electric field on OH^(*)radiation luminescence characteristics in methane-oxygen diffusion flame

作　　者：吴婧瑄 龚岩 郭庆华[1] 吴心祎 宋旭东 王辅臣[1] 于广锁[1,2] WU Jingxuan;GONG Yan;GUO Qinghua;WU Xinyi;SONG Xudong;WANG Fuchen;YU Guangsuo(Institute of Clean Coal Technology,East China University of Science and Technology,Shanghai 200237,China;State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering,Ningxia University,Yinchuan 750021,China)

机构地区：[1]华东理工大学洁净煤技术研究所,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室验室,宁夏银川750021

出　　处：《洁净煤技术》2025年第1期51-58,共8页Clean Coal Technology

基　　金：省部共建煤炭高效利用与绿色化工国家重点实验室开放课题资助项目(2022-K42);国家重点研发计划资助项目(2022YFB4101504);上海市明日之星计划资助项目(21QA1402300)。

摘　　要：火焰为非平衡弱电离等离子体,其中含有大量带电粒子、激发态自由基等物质。大量研究已经表明,将等离子体技术与燃烧领域相结合,可以显著缩短着火延迟时间、拓宽可燃极限、提高燃烧稳定性及降低污染物。基于火焰光谱诊断原理和模拟软件Maxwell,探究了直流电场对火焰形态和OH^(*)自发发光辐射的影响。结果表明:施加直流电场后电场力主要作用在火焰根部,火焰中的正离子受力向负极移动,在火焰外观上表现为其整体形态的拉伸。贫氧燃烧工况下,火焰高度与电压呈正相关,而富氧燃烧工况下,火焰高度仅随电压的改变在35.08 mm附近出现小范围波动,即贫氧工况下电场对火焰高度的影响更为显著。而结合顺电效应,施加电场后火焰宽度随直流电场的增大而减小,其变化趋势在不同氧燃当量比下保持一致。向火焰施加的直流电压小于3 kV时,OH^(*)的峰值强度没有明显改变,电压大于4 kV时,OH^(*)的峰值强度与电压呈负相关。以富氧燃烧为例,相比未施加电压的工况,OH^(*)辐射总强度在9 kV电压作用下出现10%左右的下降,即直流电场加强了火焰径向及轴向的燃料及氧气的混合。Flames are non-equilibrium,weakly ionized plasmas containing a large number of charged particles,excited state radicals and other substances.Numerous studies have shown that the combination of plasma technology and combustion field can significantly shorten the ignition delay time,extend the flammability limit,improve combustion stability and reduce pollutants.Based on the flame spectral diagnostic system and Maxwell simulation of electric field strength,the effects of DC electric field on flame morphology and OH^(*)radiation were investigated.The results show that under DC electric field,the electric field force acted mainly on the root of the flame,and positive ions in the flame were forced to move to the cathode,which is manifested as a stretching in the appearance of the flame.In oxygen-poor combustion of the flame height is positively correlated with the voltage value,whereas in oxygen-rich combustion the flame height fluctuated only in a small range around 35.08 mm with the change in voltage value,which meant the effect of DC electric field on the flame height was more significant in oxygen-poor combustion.Combined with the para-electric effect,the flame width decreased with the increase of the DC field under DC electric field,and its trend remained consistent under different oxygen-fuel equivalent ratios.The peak intensity of OH^(*)did not change significantly when the voltage value was below 3 kV,and the peak intensity of OH^(*)was negatively correlated with the voltage value when it was above 4 kV.In the case of oxygen enriched combustion,the OH^(*)content at 9 kV showed a decrease of about 10%compared to the case with no voltage applied,which meant the DC field promoted the mixing of fuel and oxygen in the radial and axial directions of the flame.

关 键 词：扩散火焰 直流电场 自发辐射 电场影响火焰 离子风 

分 类 号：TK16[动力工程及工程热物理—热能工程]