Some Aspects in Gel Propulsion Research

The combustion behavior of gel fuels containing micro and nano-sized aluminum particles were investigated in a pressurized chamber under typical ramjet conditions. Condensed combustion products were sampled in the jet plume behind the exit nozzles with two different rapid insertion probes. The chemical composition of the samples was determined and the structure of the sampled combustion products was studied with microscopic techniques. The formation of large aggregates of aluminum was observed, which leave the combustion chamber with limited oxidation. The formation of such aggregates could explain why the substitution on micro-Al with nano-Al did not led to the expected increase in combustion efficiency