Fuel injector with mixing circuit

1. A fuel injector, comprising:

a secondary injector body located downstream of a primary fuel injector, the secondary injector body having a plurality of manifolds, an inlet, and an outlet, the plurality of manifolds configured for receiving fuel and the inlet configured for receiving air;

a mixing circuit positioned within the injector body, the mixing circuit configured for receiving fuel from a first manifold of the plurality of manifolds and air from the inlet to create an air-fuel mixture that exits the outlet; and

at least one injector positioned radially outwardly from the mixing circuit, the at least one injector receiving fuel from a second manifold of the plurality of manifolds and injecting fuel to the outlet, wherein the air-fuel mixture and the fuel routed to and through the at least one injector are fluidly isolated from each other along an entire length of the mixing circuit prior to injection into a secondary combustion section of a gas turbine engine.

2. The fuel injector of claim 1 , wherein the injector body includes a central axis, wherein the mixing circuit extends along the central axis.

3. The fuel injector of claim 1 , wherein a length of the mixing circuit extends from the inlet to the at least one injector.

4. The fuel injector of claim 1 , wherein the injector body includes a converging section that terminates at the outlet.

5. The fuel injector of claim 4 , wherein a length of the mixing circuit extends into the converging section of the injector body.

6. The fuel injector of claim 1 , wherein the injector body includes an injector body length, and wherein a length of the mixing circuit is less than the injector body length.

7. The fuel injector of claim 1 , wherein the at least one injector is angled between about 30° to about 90° with respect to a central axis of the injector body.

8. The fuel injector of claim 1 , wherein the fuel injector includes at least one center circuit fuel manifold fluidly connected to the mixing circuit through a passageway defined by the injector body.

9. The fuel injector of claim 1 , wherein the fuel injector includes at least one injector manifold fluidly connected to the at least one injector.

10. A combustor for a gas turbine, comprising:

at least one primary fuel injector;

at least one secondary fuel injector that is disposed downstream of the at least one primary fuel injector, the at least one secondary fuel injector comprising:

an injector body having a plurality of manifolds, an inlet, and an outlet, the plurality of manifolds configured for receiving fuel and the inlet configured for receiving air;

a mixing circuit positioned within the injector body, the mixing circuit configured for receiving fuel from a first manifold of the plurality of manifolds and air from the inlet to create an air-fuel mixture that exits the outlet; and

at least one injector positioned radially outwardly from the mixing circuit, the at least one injector receiving fuel from a second manifold of the plurality of manifolds and injecting fuel to the outlet, wherein the air-fuel mixture and the fuel routed to and through the at least one injector are fluidly isolated from each other along an entire length of the mixing circuit prior to injection into a secondary combustion section of a gas turbine engine.

11. The combustor of claim 10 , wherein the injector body includes a central axis, wherein the mixing circuit extends along the central axis.

12. The combustor of claim 10 , wherein a length of the mixing circuit extends from the inlet to the at least one injector.

13. The combustor of claim 10 , wherein the injector body includes a converging section that terminates at the outlet.

14. The combustor of claim 13 , wherein a length of the mixing circuit extends into the converging section of the injector body.

15. The combustor of claim 10 , wherein the injector body includes an injector body length, and wherein a length of the mixing circuit is less than the injector body length.

16. The combustor of claim 10 , wherein the at least one injector is angled between about 30° to about 90° with respect to a central axis of the injector body.

17. The combustor of claim 10 , wherein the at least one secondary fuel injector includes at least one center circuit fuel manifold fluidly connected to the mixing circuit through a passageway defined by the injector body.

18. The combustor of claim 10 , wherein the at least one secondary fuel injector includes at least one injector manifold fluidly connected to the at least one injector.

19. A combustor for a gas turbine, comprising:

at least one primary fuel injector;

at least one secondary fuel injector that is disposed downstream of the at least one primary fuel injector, the at least one secondary fuel injector comprising:

an injector body having a central axis, a plurality of manifolds, an inlet, and an outlet, the plurality of manifolds configured for receiving fuel and the inlet configured for receiving air;

a mixing circuit positioned within the injector body and extending along the central axis, the mixing circuit configured to receive fuel from a first manifold of the plurality of manifolds and air from the inlet to create an air-fuel mixture that exits the outlet; and

at least one injector positioned radially outwardly from the mixing circuit, the at least one injector receiving fuel from a second manifold of the plurality of manifolds and injecting fuel to the outlet, the at least one injector being angled with respect to the central axis, wherein the air-fuel mixture and the fuel routed to and through the at least one injector are fluidly isolated from each other along an entire length of the mixing circuit prior to injection into a secondary combustion section of a gas turbine engine.