Dual-Plate Injector for Throttling of Hydrogen Peroxide Monopropellant Thruster

Abstract

This study provides an experimental analysis of the throttling methods implemented using a throttleable injector that generates a thrust in the range 24-64% on a 50 N monopropellant thruster using 90 wt.% hydrogen peroxide and MnO2/PbO/Al2O3. The injector proposed in this study is a dual-plate injector. It is capable of controlling the mass flow rate using radial slotted and showerhead-type plates. The slotted plate was rotated and pressed against the showerhead-type plate by intersecting a number of injection ports to control the mass flow rate. Firing tests were conducted over the throttling range to verify the feasibility of the concept of the dual-plate injector. The experimental data of the injectant flow rate and chamber pressure were analyzed parametrically. It was observed that the dual-plate injector had a characteristic velocity in the range 81-97% depending on the range of thrust. In addition, a correlation was observed between the characteristic velocity efficiency and response time of the injector under varying injection conditions; that is, the characteristic velocity tends to increase with a decrease in the response time. The result can be applied to optimal control systems, and also be used to execute advanced missions accurately using a monopropellant thruster.