Plasma Jet Igniter Properties : Analysis by Electron Temperature Measurement

Abstract

A temporal change of local electron temperature on the central axis of the plasma jet was measured in an enivironment of hydrogen. The electron temperature was measured by applying the two-line radiance ratio method. The diffusion of plasma jet was clarified for various plasma jet igniter configurations and supplied electrical energies. The relationship between the characteristic length of the igniter and the plasma jet was elucidated. The progression of the plasma jet was influenced by the waveform of the discharged voltage in the vicinity of the igniter. The electron temperature and the length of the plasma jet increased as cavity volume decreased and as orifice diameter increased. It appears that an igniter which has a small characteristic length is favorable with regard to penetration of the plasma jet and to generation of a high electron temperature. Therefore, it is considered that the plasma jet igniter configurations exert different influences on plasma jet penetration and combustion enhancement.