Some governing parameters of plasma torch igniter/flameholder in a scramjet combustor

Effects of various operational parameters of plasma torch igniters/flameholders were experimentally studied in a hydrogen-fueled supersonic combustor with a rectangular cross section. The stagnation temperature of the airstream at the ignition limit almost linearly decreased as input electric power increased, although it did not significantly change with the flow rate of feedstock. Effectiveness of the argon plasma torch igniter was remarkably improved by adding a small fraction of hydrogen, but it showed rather modest improvement for further increase of the hydrogen contents. Modification of the combustor top wall design led to successful ignition of fuel jets injected from opposing side walls by a single plasma torch igniter and great reduction of airstream temperature at the ignition limit.