Mutual effects between a gliding arc discharge and a premixed flame

Mutual effects between a gliding arc (GA) discharge at atmospheric pressure and a premixed CH4/air flame were experimentally investigated. Effects of the flame on the GA were studied using simultaneous measurements of the current, the voltage, and the instantaneous images of the plasma columns. The GA in the flame has a thicker and more diffusive plasma column, and it is more frequently ignited at a smaller breakdown voltage than that in the air. The GA extension velocity and the gliding velocity in the flame are larger than in the air. The electrode voltage drop of the GA discharge in the flame is about 160 V, whereas that in the air is about 220 V. Compared with the GA in the air, the different features of the GA in the flame can be explained by high-temperature, weakly ionized, and species-abundant environment that are generated by the premixed CH4/air flame. Effects of the gliding arc discharge on the premixed flames were demonstrated using planar laser-induced fluorescence of hydroxyl radicals (OH) and formaldehyde (CH2O). OH and CH2O can be formed in the CH4/air mixture in the presence of the GA due to kinetic effects, and the increase of OH and CH2O shows the great potential of the GA for combustion enhancement.