Flames with plasmas

Abstract

Non-equilibrium plasma discharges can create a favorable environment for combustion processes, at low energy cost. “How favorable?” and “How low?” are two open questions that can be answered only by gaining a deep understanding of the coupling between flames and plasmas. This paper reviews recent progress in plasma-assisted combustion with a special focus on flame dynamics. First, different non-equilibrium plasma discharges are presented and their effects on flame properties are discussed. Then, an additional level of complexity is introduced by considering the effect of such plasmas on the coupling between flames and acoustic waves. While initial results suggested that the best plasma actuation would combine thermal and chemical effects, a shift towards favoring a chemical impact is emerging. Reasons for this shift are explained and future research directions are finally proposed.