Demonstration of Polyethylene Nitrous Oxide Catalytic Decomposition Hybrid Thruster with Dual-Catalyst Bed Preheated by Hydrogen Peroxide

Although various studies on nitrous oxide as a prospective green propellant have been recently explored, a polyethylene nitrous oxide catalytic decomposition hybrid thruster was barely demonstrated due to an inordinately high catalyst preheating time of a heater, which led to the destruction of components. Therefore, hydrogen peroxide was used as a preheatant, a substance to preheat, with a dual-catalyst bed. The thruster with polyethylene (PE) as a fuel, N2O as an oxidizer, H2O2 as the preheatant, Ru/Al2O3 as a catalyst for the oxidizer, and Pt/Al2O3 as a catalyst for the preheatant was arranged. A preheatant supply time of 10 s with a maximum catalyst bed temperature of more than 500 °C and without combustion and an oxidizer supply time of 20 s with a burning time of approximately 15 s were decided. Because the catalyst bed upstream part for decomposing the preheatant was far from the post-combustion chamber, the post-combustion chamber pressure increased and the preheatant mass flow rate decreased after a hard start during the preheatant supply time. Moreover, because the catalyst bed upstream part primarily contributed to preheating, the maximum catalyst bed temperature was less than the decomposition temperature of the preheatant during the preheatant supply time. Additionally, because the catalyst bed downstream part for decomposing the oxidizer was far from the post-combustion chamber, the post-combustion chamber pressure decreased and then increased during a transient state in the oxidizer supply time.