Multiple-propellant air vehicle and propulsion system

A method of improving the fuel system of a propulsion system having a rocket casing with a combustion chamber having a combustor liner and an exhaust gas throat having a throat liner with a fuel passageway adjacent to and surrounding the combustor liner and the throat liner, comprising:

• (a) passing a hydrocarbon fuel selected from the group of hydrocarbons having a freezing point of about 150.degree. R. to about 200.degree. R. and a boiling point of about 275.degree. R. to about 425.degree. R. through the fuel passageway;
• and
• (b) providing heat from the combustion of fuel in the combustion chamber to the fuel passageway by radiation through the combustor liner and the throat liner;
• whereby the hydrocarbon fuel is heated at a temperature sufficient to cause the endothermic pyrolysis of the hydrocarbon in the fuel passageway, and the heat removed from the combustion chamber through the combustor liner and throat liner reduces the temperature in the combustion chamber at the combustor liner and the throat liner so the thermal limits of the combustor liner and throat liner are not exceeded.

A propulsion system which utilizes a hydrocarbon fuel, comprising:

• (a) a rocket casing having a combustor chamber with a combustor liner and a nozzle throat chamber with a nozzle throat liner, whereby the combustor liner and nozzle throat liner provide high heat flux from combustion within the rocket casing and the temperature of the liners would exceed their thermal limits if not cooled;
• (b) a fuel passageway for the hydrocarbon fuel adjacent to and surrounding the combustor liner and the nozzle throat liner;
• (c) a source of hydrocarbon fuel of the type having a freezing point of about 150.degree. R. to about 200.degree. R. and a boiling point of about 275.degree. R. to about 425.degree. R.;
• (d) means for providing fuel flow of the hydrocarbon fuel in the fuel passageway;
• and
• (e) a plurality of flow directing vanes disposed in the fuel passageway to direct the fuel in the fuel passageway circumferentially whereby the fuel travels a longer path through the passageway and thereby increases the residence time of fuel in the passageway;
• endothermic pyrolysis of the hydrocarbon fuel occurs;
• and the combustor liner and throat liner are cooled by the endothermic pyrolysis of the hydrocarbon in the fuel passageway.

A method of improving the fuel system of a propulsion system having a rocket casing with a combustor chamber having a combustor liner and an exhaust gas throat having a throat liner with a fuel passageway adjacent to and surrounding the combustor liner and the throat liner, comprising:

• (a) passing a hydrocarbon fuel selected from the group of hydrocarbons having a freezing point of about 150.degree. R. to about 200.degree. R. and a boiling point of about 275.degree. R. to about 425.degree. R. through the fuel passageway;
• (b) providing heat from the combustion of fuel in the combustion chamber to the fuel passageway by radiation through the combustor liner and the throat liner;
• and
• (c) increasing the residence time of fuel in the fuel passageway by a plurality of flow directing vanes disposed in the fuel passageway to direct the fuel in the fuel passageway circumferentially, the fuel traveling a longer path through the passageway to increase the residence time therein, whereby the hydrocarbon fuel is heated at a temperature sufficient to cause the endothermic pyrolysis of the hydrocarbon in the fuel passageway, and the heat removed from the combustion chamber through the combustor liner and throat liner, causing the endothermic pyrolysis of the hydrocarbon fuel, reduces the temperature in the combustion chamber at the combustor liner and the throat liner so the thermal limits of the combustor liner and throat liner are not exceeded.