Flames are non-equilibrium,weakly ionized plasmas containing a large number of charged particles,excited state radicals andother substances. Numerous studies have shown that the combination of plasma technology and combustion field can significantly shortenthe ignition delay time,extend the flammability limit,improve combustion stability and reduce pollutants. Based on the flame spectraldiagnostic 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,andpositive ions in the flame were forced to move to the cathode,which is manifested as a stretching in the appearance of the flame. Inoxygen-poor combustion of the flame height is positively correlated with the voltage value,whereas in oxygen-rich combustion the flameheight fluctuated only in a small range around 35.08 mm with the change in voltage value,which meant the effect of DC electric field onthe flame height was more significant in oxygen-poor combustion. Combined with the para-electric effect,the flame width decreased withthe increase of the DC field under DC electric field,and its trend remained consistent under different oxygen-fuel equivalent ratios. Thepeak 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 adecrease of about 10% compared to the case with no voltage applied,which meant the DC field promoted the mixing of fuel and oxygen inthe radial and axial directions of the flame.

吴婧瑄(1998—),女,甘肃兰州人,硕士。E-mail:y30211053@mail.ecust.edu.cn

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WU Jingxuan,GONG Yan,GUO Qinghua,et al. Study on the effect of direct current electric field on OH* radiationluminescence characteristics in methane-oxygen diffusion flame[J].Clean Coal Technology,2025,31(1):34−41.