Feasibility Study of Low Frequency Plasma for Bipropellant Thruster Ignition

Abstract

To achieve reliable, low power ignition source for methane and oxygen thruster, a low frequency plasma is proposed. Helium is used as a working fluid for the plasma jet because it is easier to ionize than oxygen and methane. The heat of helium plasma must then be transferred to the mixed gases of oxygen and hydrocarbon, which then ignite. To understand the mechanism of this ignition process, we performed an experiment to visualize with a high speed video camera by using gaseous methane and oxygen under atmospheric conditions in a thruster configuration. Discharges in the propellant mixture were observed prior to ignition which then led to ignition. This experiment reveals, actually, that the helium plasma itself is not the source of ignition in this configuration. Nomenclature φ = Equivalence ratio