Rocket engine with cryogenic propellants
A cryogenic-propellant rocket engine includes: at least a first tank for a first liquid propellant; a second tank for a second liquid propellant; a third tank for an inert fluid; an axisymmetrical nozzle including a combustion chamber, a device for injecting first and second liquid propellants into the combustion chamber, a nozzle throat, and a divergent section; and a heater device including at least one duct for conveying the inert fluid and arranged outside the nozzle in immediate proximity thereof, but without making contact therewith, to recover energy of thermal radiation emitted when the rocket engine is in operation and to heat the inert fluid.
1. A cryogenic-propellant rocket engine comprising:
at least a first tank for a first liquid propellant;
a second tank for a second liquid propellant;
a third tank for an inert fluid that is used to pressurize at least one of the first and second tanks;
an axisymmetrical nozzle including a combustion chamber, a device for injecting first and second liquid propellants into the combustion chamber, a nozzle throat, and a divergent section;
a heater device including at least one duct for conveying the inert fluid and arranged outside the nozzle in an immediate proximity of the nozzle, but without making contact with the nozzle, to recover energy of thermal radiation emitted when the rocket engine is in operation and to heat the inert fluid,
the heater device comprising a plate in a form of a portion of a conical frustum that extends exclusively around the divergent section of the nozzle over an angle σ lying in a range 30° to less than 360°.
2. A rocket engine according to claim 1 , wherein the heater device comprises a metal structure in which the inert fluid for heating flows and a fine layer that is strongly absorbent from a thermal radiation point of view deposited at least on walls that face the nozzle constituting a radiant power source.
3. A rocket engine according to claim 1 , wherein the plate of the heater device presents a thickness lying in a range 5 mm to 15 mm.
4. A rocket engine according to claim 1 , wherein the plate of the heater device includes a network of continuous channels of rectangular or circular section.
5. A rocket engine according to claim 1 , wherein the inert fluid is helium.
6. A rocket engine according to claim 1 , wherein said first tank for a first liquid propellant includes at least one tank of liquid oxygen.
7. A rocket engine according to claim 6 , further comprising pipes making a connection between the heater device and the liquid oxygen tank to supply it with said inert fluid comprising pressurizing helium.
8. A rocket engine according to claim 1 , further comprising pipes making a connection between the heater device and the first tank comprising a liquid oxygen tank to supply it with said inert fluid comprising pressurizing helium.
9. A rocket engine according to claim 1 , wherein the divergent section of the nozzle is made of thermostructural carbon-carbon, carbon-ceramic, or ceramic-ceramic composite material.
10. A rocket engine according to claim 1 , wherein the conical frustum extends exclusively around the divergent section of the nozzle such that the plate does not overlap the combustion chamber, the device for injecting first and second liquid propellants, or the nozzle throat in a radial direction of the nozzle.
11. A rocket engine according to claim 1 , wherein the device for injecting first and second liquid propellants is an injector.