Thermal characteristics of expandable graphite as a burning rate enhancer in hybrid propulsion

Hybrid propulsion, consisting of solid fuel and liquid oxidizer, exhibits major advantage regarding safety, development costs, energetic performance, controllability. Hence, it has been considered for space other propulsion programs. One the characteristic features hybrid motors, that may be disadvantage, is their relatively low thrust due to regression rate typical polymeric fuels. This research group had revealed a small fraction an expandable graphite (EG) additive could double burning motors. EG intercalated form graphite, elongating swelling, getting worm-like string shape at elevated temperatures. In earlier work was hypothesized enhanced heat transfer via conduction through strings protruding from hot surface, significant parameter increasing rate. present investigation, thermal analysis ignition temperature polyester containing 5 wt% EG, substantially lower than pure polymer, which promote higher as well. High-speed photography surface EG-containing fuels well individual particles during controlled heating, demonstrated dynamic behavior resulting in formation longer by order magnitude compared original particles. The different phenomena were related observation