Method and device for supplying a space propulsion engine with liquid cryogenic propellants

1. A method for supplying a combustion chamber of a space propulsion engine with cryogenic liquid fuel and oxidizer propellants, the method comprising: pressurizing a fuel propellant tank and an oxidizer tank at a constant pressure;

mixing the fuel propellant from the fuel propellant tank and the oxidizer propellant from the oxidizer tank to form a propellant mixture;

feeding said propellant mixture through via an orifice of an enclosure of a propellant injector, wherein the fuel propellant and oxidizer propellant are mixed at constant pressure upstream of the propellant injector enclosure; and

injecting said propellant mixture from said propellant injector enclosure into said combustion chamber, wherein flow rate of the propellant mixture into the combustion chamber is varied by varying geometry of the propellant injector, and the injection of the propellant mixture from the propellant injector enclosure into the combustion chamber is at constant pressure.

2. The method as claimed in claim 1 , wherein the fuel propellant is liquid methane and the oxidizer propellant is liquid oxygen.

3. The method as claimed in one of claims 1 , wherein said propellant mixture is ignited inside the combustion chamber and said propellant mixture is injected into the combustion chamber at supersonic velocity.

4. A device for supplying cryogenic liquid fuel and oxidizer propellants to a combustion chamber of a space propulsion engine, said device comprising:

a fuel propellant tank;

an oxidizer propellant tank;

a pressurizing unit configured to pressurize the fuel propellant tank and oxidizer propellant tank to a constant pressure;

a mixer configured for mixing said fuel propellant from said fuel propellant tank with said oxidizer propellant from said oxidizer propellant tank at constant pressure and produce a propellant mixture; and

a propellant injector comprising an enclosure,

wherein:

said propellant injector enclosure includes an inlet orifice in fluid communication with said mixer, and

said propellant injector is configured for varying flow rate of said propellant mixture from said propellant injector enclosure into said combustion chamber at constant pressure.

5. The device as claimed in claim 4 , wherein said propellant injector further comprises a plurality of needles, each needle cooperating with a calibrated orifice.

6. The device as claimed in claim 5 , wherein the plurality of needles are supported by a first plate, the plurality of calibrated orifices are in a second plate and the propellant injector is configured for imparting relative movement between said first plate and second plate to decrease or increase distance between the first plate and second plate.

7. The device as claimed in claim 4 , further comprising a cooling circuit around said combustion chamber, wherein said cooling circuit is configured as the mixer for mixing said fuel propellant and said oxidizer propellant at constant pressure to produce the propellant mixture, and said cooling circuit is configured for feeding said propellant mixture into said propellant injector enclosure.

8. The device as claimed in claim 4 , wherein a cooling circuit forms said mixer.

9. The device as claimed in one of claims 4 , wherein said mixer is external to said engine.