Experimental Study of Pressure Gain Combustion with Hypergolic Rocket Propellants

Abstract

This paper summarizes experimental observations of pulsed combustion occurring in a 4.5 cm diameter, nozzleless rocket combustor for pressure gain combustion applications. The combustor featured an impinging jet injector and operated on high-concentration hydrogen peroxide with a catalyst-laced hydrocarbon-based fuel. Pressure oscillations in the 200–700 Hz range were found. For a 10 bar manifold pressure, peak-pressure responses exceeding 60 bar were recorded in the feed system. Transient propellant spray destruction and formation were observed through an optically accessible combustor section. The pulse combustion frequency was tightly tied to atomization, mixing, and hydrogen peroxide decomposition processes; furthermore, frequency was well correlated with the injection velocity for a given injector design. While a precise description is still lacking, the combustion of a mixture of decomposed hydrogen peroxide and fuel appears to be best described as a constant-volume combustion event.