Droplet combustion, microexplosion, and sooting characteristics of several energetic liquid propellants

The combustion characteristics of droplets of four newly synthesized energetic fuels, namely, 1) 1,4-dimethyl ester cubane (which is a solid slightly soluble in conventional liquid fuels), 2) dihydrobenzvalene, 3) phenyl azide, and 4) carborane (which are all liquids), were experimentally identified and quantified. Results show that the gradual concentration and eventual condensation of dimethyl ester cubane dissolved in benzene can lead to strong droplet microexplosion; that the three liquid fuels all soot profusely, with the sooting propensity, when compared with other fuels, being in the following order: JP-10 < benzene approximate to dihydrobenzvalene < phenyl azide < carborane; and that phenyl azide additionally exhibits fast gasification rates, advanced microexplosion events, and sensitivity to halide addition. It is emphasized that a high-energy-density fuel does not automatically imply that it is fast burning, and that it must also possess desirable combustion characteristics, especially minimal sooting formation, before it can be considered for use as a jet fuel or jet fuel additive.