High-Speed Visualization of Flame Reaction Zone Using a Positive Point-to-Plane Corona Discharge

We have used a pulsed corona discharge to obtain time-resolved spectrally filtered 337.1-nm N₂(C rarr B) emission images for the visualization of the reaction zone (flame front) of a premixed propane-air flame. The low-density region at the flame front allows one to guide the streamer along the reaction zone during the initial stages of the pulsed discharge, while the temperature-dependent electron-detachment/attachment rate allows for the increased conductivity of the plasma after the discharge has been fully established. Images with 500-shot accumulations are presented to clearly illustrate the concept, while the ability for greater time resolution is discussed as an attractive means for imaging small-scale turbulent instabilities in a flame reaction zone.