Effect of Gas Dynamics on Discharge Modes and Plasma Chemistry in Rotating Gliding Arc Reactor

This article investigates the effect of gas flow rate on arc discharge mode and plasma chemistry in a nonmagnetic rotating gliding arc reactor. This article is conducted using oxygen as a plasma forming gas under transient (5 LPM), turbulent (25 LPM), and highly turbulent (50 LPM) flow conditions. The voltage-current (V-I) characteristics reveal discharge modes, such as glow mode under transient flow (I <; 1 A), glow-spark transition mode under turbulent flow (I <; 1 A & I ≫ 1 A), and spark mode under highly turbulent flow (I ≫ 1 A). Arc completes full rotation under transient flow, whereas it is blown off before completing full rotation under turbulent flows. The captured optical emission lines of the discharge indicate domination of excitation reactions under glow and glow-spark transition modes and domination of both the excitation and electron impact ionization reactions under spark mode. These observations reveal that the gas dynamics changes the discharge mode of the rotating arc that in turn alters the plasma chemistry, which is a positive feature to promote specific reaction pathways.