chapter  4
16 Pages

DECOMPOSITION CHEMISTRY OF HIGH-ENERGY-DENSITY FUELS BY FLOW TUBE MASS SPECTROMETRY

An important strategy for improvement of propulsion system performance is

utilization of fuels and propellants that have signicantly enhanced energy den-

sity compared to normal hydrocarbons. For liquid-fueled applications, strained

hydrocarbons are a particularly appealing class of candidate fuel molecules,

because they should work in conventional combustors and fuel systems with

minimal modication. Their high-energy densities result mainly from increased

density compared to normal hydrocarbons; however, they can have up to

140 kcal/mole of strain energy built into the molecular framework in the

form of distorted bond angles. While this does not greatly increase the heat of

combustion, the strain energy changes the pyrolysis behavior of the molecules

substantially, which should make it possible to tune the ignition/combustion

Figure 4.1 Strained hydrocar-

bon molecules discussed in the pa-

per: (a) quadricyclane, (b) norbor-

nadiene, (c) cubane, (d) 1-azo-3-

ethylbicyclo[1.1.0]butane

ior might be substantially improved by

generation of reactive species early in the

combustion process or by micro-

explosions in fuel droplets. A few simple

strained molecules are shown in Fig. 4.1.