Parametric Ignition Study of a Green Hypergolic Hybrid Rocket Fuel
Syamantak Nath, Iker Laso, Joseph K. Lefkowitz
Abstract
View Video Presentation: https://doi.org/10.2514/6.2022-1484.vid The ignition characterization of a non-toxic, hypergolic, hybrid rocket propellant combination is described in this paper. The metal-hydride based propellant consists of rocket grade hydrogen peroxide (RGHP) as oxidizer, high density polyethylene (HDPE) as fuel and sodium borohydride (NaBH4) as the hypergolic additive, embedded in the HDPE fuel matrix. Using a drop-test setup, ignition delay was measured as a function of RGHP concentration in water, NaBH4 additive weight loading in the HDPE matrix, drop impact velocity, droplet diameter and diluent gas. Ignition delays as low as 3 ms were obtained, comparable to the performance of state-of-the-art liquid bipropellants. Most ignition delay values were lower than 10 ms. All the parameters, encompassing thermo-physical, fluid dynamic and environmental factors, influenced ignition delay with drop impact velocity being a significant parameter. The encouraging results imply that this combination is promising as a high-performance, yet cheap and non-toxic propellant for hybrid rocket applications. Further, the results also show a need to include droplet dynamics in the study of hypergolic propellants.