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Evaluation of the National Aerospace Initiative (2004) / Chapter Skim
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Appendix E: Fuels Research
Pages 122-126

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From page 122...
... Hydrogen has a much higher specific heat than hydrocarbon fuels, and assuming that T is the same, is considered to have a higher heat capacity than hydrocarbon fuels; however, less hydrogen mass is required to achieve a given amount of heat release, so the hydrogen fuel flow rate is lower than that of a hydrocarbon. A more relevant measure of heat sink potential is the ratio of specific heat to the heat of combustion, which brings hydrocarbon fuels more in line with hydrogen in terms of heat capacity (within a factor of 2 or 3)
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From page 123...
... Extensive discussions inside the Air Force Propulsion Directorate in the mid-1980s led to an effort to develop the endothermic potential of thermally/catalytically cracked liquid hydrocarbons using commercially available, wall-mounted zeolite catalysts (Spadaccini et al., 1993a)
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From page 124...
... The engineering required to convert the hydrocarbon flight test vehicle to a successful standoff weapon for attacking time-critical targets is considered to be outside the scope of this research proposal. The state of the art appears to be Mach 6-7 for this type of expendable application and current endothermic fuel technology.
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From page 125...
... To extend the Mach number capability of nonhydrogen-fueled hypersonic vehicles, one has to either improve the fuel heat sink capability or reduce the heat load from the vehicle into the fuel. The use of high-temperature ceramic engine structures appears to be capable of significantly reducing the required engine cooling (since the heat load into the fuel is proportional to the Tcombustion less the Tsurface driving force)
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From page 126...
... WRDC-TR-89-2141. East Hartford, Conn.: United Technologies Research Center.
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Key Terms

  • hydrocarbon fuels
  • endothermic fuels
  • heat capacity
  • endothermic fuel
  • sink capability

  • sensible heat
  • specific heat
  • endothermic heat
  • fuel heat
  • hypersonic vehicles

  • conventional endothermic
  • heat load
  • sink capacity
  • technologies research
  • endothermic hydrocarbon

  • hydrocarbon flight
  • fuel research
  • endothermic methylcyclohexane
  • fuels research
  • hydrocarbon fuel

  • propulsion directorate
  • endothermic capacity
  • combustion performance
  • proposed endothermic
  • lower mach

  • flight test
  • united technologies
  • flow rate
  • hydrocarbons using
  • research proposal


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