Plasma Ignition and Stabilization of Flames
General Features of Plasma-Assisted Ignition and Combustion
Spark ignition is one of the oldest applications of plasma, known and successfully applied for thousands of years. Even in the automotive industry, spark ignition has been applied for more than a hundred years. Nevertheless, other plasma discharges, especially, non-thermal discharges, have been attracting more and more attention for use in ignition and stabilization of flames. An example, in this regard, is the non-thermal plasma ignition of fuel–air mixtures at moderate pressures and high velocities, including ignition in supersonic flows, plasma enhancement of combustion at atmospheric pressure, and stimulation of combustion of lean mixtures (Anikin et al., 2005; Starikovskaia, 2006). Numerous investigations have been focused on plasma ignition and stabilization of flames. The effectiveness of spark ignition relies on the essential non-uniformity of the thermal plasma of spark discharges and, therefore, restrictions of the system geometry (see, for example, Thiele, Warnatz, & Maas, 2000). Relevant application of thermal arc discharges, related in particular to hypersonic flows, has been analyzed, for example, by Takita (2002) and Matveev et al. (2005). Initiation of flame by a short-pulse thermal discharge and a conventional arc has been investigated in CH4–air mixtures using the time-resolved interferometry by Maly and Vogel (1979). The ignition effect of gliding arc discharges, which generates non-thermal plasma but also can result in some controlled heating, has been analyzed by Ombrello et al. (2006a, b).