Chamber Volume Effects on Hypergolic Pulse Detonation Rocket Engine

Abstract

Experimental results from a valveless pulsed detonation rocket engine concept with hypergolic propellants are detailed. The thruster employed a pintle injector and a simple combustor geometry with an open end. Flow field characterization followed from test measurements from high-speed pressure transducers and ionization gauges placed in the chamber. Propellant manifold feed pressures of 100-200 psi resulted in peak pulsed combustion pressure reaching 10,000 psi. Baseline pulsed combustion frequency ranged from 300-500 Hz. Experiments conducted with a doubled chamber length showed little impact on peak pulsed pressures but indicated a 15% decrease in pulsation frequency. The data suggests that the pulsation frequency is dependent on dynamic orifice response, chamber dimensions (diameter and length), and the chemical ignition delay of the hypergolic propellant combination. Experiments showed repeatable pulsed behavior with the need for robust injection techniques and instrumentation.