A Study of Plasma-Stabilized Diffusion Flames at Elevated Ambient Temperatures

We report on a study of the use of repetitive ultrashort pulsed plasma discharges in stabilizing a lifted methane jet diffusion flame in elevated temperature (855 K–975 K) vitiated coflow. CH chemiluminescence images are used to record the flame liftoff height, which serves as a measure of the flame stability. The results show that, for the same reduced electric field ($E/n$), the stabilizing ability of the discharge in the investigated temperature range diminishes with increasing coflow temperature. Based on the results of a zero-dimensional transient chemistry simulation, it is conjectured that the reduced propensity for stabilization at elevated temperature is caused by the rapid depletion of $\hbox{H}_{2}$ and CO formed in the postplasma gas, under high ambient temperature conditions.