Dual-injector fuel injector system

1. A fuel injector system for injecting fuel into a turbomachine combustion chamber, the system comprising:

first and second fuel injectors, the first injector being positioned at the center of the injector system so as to inject a first fuel spray, and the second injector surrounding the first injector so as to inject a second fuel spray of generally annular shape around the first fuel spray; and

first and second air admission passages associated respectively with the first and second injectors in such a manner as to form respective first and second air/fuel mixtures,

said injector system further comprising an air admission duct with outlet orifices opening out between the first and second injectors in such a manner as to create a separator air film between the respective combustion zones of the first and second air/fuel mixtures.

2. A fuel injector system according to claim 1 , wherein the second injector presents a circular injection slot surrounding the first injector.

3. A fuel injector system according to claim 1 , wherein the second injector presents a plurality of injection orifices disposed in a circle around the first injector.

4. An injector system according to claim 1 , wherein the first injector, the first air admission passage, and the second injector form part of a first assembly designed to be mounted on a second assembly comprising the second air admission passage, said second assembly being designed to be mounted on said combustion chamber.

5. An injector system according to claim 1 , comprising, around the first injector and in this order: the first air admission passage, the air admission duct, the second injector, and the second air admission passage.

6. An injector system according to claim 4 , comprising, around the first injector and in this order: the first air admission passage, the air admission duct, the second injector, and the second air admission passage.

7. An injector system according to claim 1 , wherein the first air admission passage is defined between two annular walls, an inner wall, and an outer wall, the outer wall being extended downstream by a diverging wall.

8. An injector system according to claim 7 , wherein said air admission duct includes a first series of outlet orifices passing through said diverging wall near the downstream end thereof, said orifices being disposed in a circle around the first injector.

9. An injector system according to claim 8 , wherein said air admission duct includes a second series of outlet orifices passing through said diverging wall upstream from said first series of outlet orifices, said orifices being disposed in a circle around the first injector.

10. An injector system according to claim 1 , wherein the second air admission passage is defined between two annular walls, an inner wall, and an outer wall, the outer wall being extended downstream by a diverging wall, said diverging wall being pierced, near its downstream end, by a series of orifices disposed in a circle around the second injector.

11. A turbomachine combustion chamber fitted with an injector system according to claim 1 .

12. A turbomachine combustion chamber according to claim 11 , comprising inner and outer annular walls that are mutually spaced apart, a chamber end wall disposed between said annular walls in the upstream region of said chamber, and an injector system in which the first injector, the first air admission passage, and the second injector form part of a first assembly designed to be mounted on a second assembly comprising the second air admission passage, said second assembly being secured to the end wall of the chamber.

13. A turbomachine including a combustion chamber according to claim 11 .