Stabilized Superthermite Gelled Kerosene : towards Advanced Green Propellant Systems

Although hydrazine is the most common liquid propellant fuel, it is highly toxic and cancerogenic. Gelled hydrocarbons could be the greener substitute. Kerosene was gelled using fumed silica nanoparticles (NPs). Reactive metal particles can act as a high energy dense material (HEDM). With this aim, gelled kerosene was loaded with aluminum (Al) NPs. In combustion, SiO2/Al can induce vigorous exothermic superthermite reaction. Gelled kerosene demonstrated shear thinning behaviour, with high gel stability at 90 g centrifugal acceleration. The silica NPs could form a network via hydrogen bonding of Si‒OH groups; this network could be broken down under a high shear rate. Aluminized gelled kerosene formulation (8 wt.% SiO2 + 8 wt.% Al) preserves the shear thinning behaviour, i.e. it reached the viscosity of liquid kerosene at a shear rate below 25000 S -1. This value lies within the range of pumping systems in rocket engines. Metallized gelled formulations demonstrated yield stress that is required to avoid phase separation and sedimentation during storage. Stabilised superthermite NPs not only offered enhanced characteristic exhaust velocity by 6% using the ICT thermodynamic code. Furthermore, they could induce vigorous exothermic superthermite reactions.