Promotion of Combustion by Electric Discharges (The Role of Vibrationally Excited Species)

Abstract

It has been shown recently that plasma jets or electric discharges work effectively on the flame stabilization or the promotion of combustion reaction in several combustion experiments. In the first part of this review, the outlines of two investigations on the mechanism of combustion-reaction promotion, one is the case of injection of plasma jet and the other is the case of application of direct electric discharge, there exists active participation of vibrationally excited species produced by electric discharges on the promotion of combustion reaction through the route where vibrationally excited fuel molecules transform into radicals via specific reactions with high rate constant, although in the case of plasma jet, the participation of vibrationally excited species may be less important compared to that of specific radicals involved in plasma jet. The second part of this review refers to three experiments on the effect of plasma jet in supersonic combustions or a high-velocity stream combustion, of which results also suggest the role of vibrationally excited species on combustion promotion.