Demonstration of ammonia borane-based hypergolic ignitor for hybrid rocket

Abstract

The low toxicity hypergolic solid fuels (HSFs) and hydrogen peroxide (H2O2) oxidizer have been demonstrated as environment-friendly hybrid propellants. In the present study, a new HSF containing ammonia borane (AB), Pd-C, and paraffin wax, was fabricated in the form of the hypergolic ignitor for the hybrid rocket. Furthermore, the atmospheric combustion test (ACT) and hot-fire test (HFT) with HSF ignitor, PMMA or PE fuel, and 95% H2O2 oxidizer were performed using fuel-exposed-hybrid-combustor; studied the ignition reliability and combustion characteristics of HSF. The hypergolic ignition of HSF initiated through Pd-C followed by AB combustion with H2O2 was observed by using the high-speed camera images of ACT. A HFT with a ground thrust of 120 N exhibited the rising time and pressure instability of 137 ms and +/- 4.00%, respectively. Moreover, smooth combustion transition from HSF to PE was achieved with stable chamber pressure and no hard-start. The results suggest that the HSF ignitor containing AB may be the suitable preference for the hypergolic hybrid rocket.