Multi-fuel bluff-body piloted high-shear injector and method of using same

1. A combustor for a gas turbine engine, the combustor comprising:

a combustion chamber;

a hood chamber separated from the combustion chamber by a bulkhead, the bulkhead comprising at least one opening extending between the hood chamber and the combustion chamber;

a fuel injector extending through the at least one opening, the fuel injector comprising a fuel injector body including an outer radial surface and a tip surface which intersects the outer radial surface, the tip surface located at a downstream end of the fuel injector, the fuel injector further comprising a primary fuel passage comprising a primary fuel outlet located in a center of the tip surface within the combustion chamber, the fuel injector further comprising a secondary fuel passage comprising a plurality of secondary fuel outlets located within the hood chamber, at least a portion of the secondary fuel passage being annular and radially outside of the primary fuel passage, the primary fuel passage configured to inject a hydrogen-based primary fuel directly into the combustion chamber and the secondary fuel passage configured to inject a secondary fuel, different than the hydrogen-based primary fuel, into the combustion chamber; and

a swirler extending through the at least one opening and located radially outside of the fuel injector with respect to a fuel injector center axis, the swirler extending from a first axial end to a second axial end, the first axial end spaced upstream of the at least one opening and the second axial end spaced downstream of the at least one opening, the second axial end defining a swirler exit plane;

wherein the tip surface extends along the swirler exit plane.

2. The combustor of claim 1 , wherein the combustion chamber is defined between an inner shell and an outer shell and wherein the bulkhead extends between the inner shell and the outer shell.

3. The combustor of claim 1 , wherein the tip surface extends along the swirler exit plane from the primary fuel outlet to the outer radial surface.

4. The combustor of claim 1 , wherein the fuel injector further comprises a cooling air passage comprising a plurality of air outlets located in the tip surface radially outside of the primary fuel outlet with respect to the fuel injector center axis.

5. The combustor of claim 4 , wherein the fuel injector includes an annular air gap disposed within the fuel injector body between the primary fuel passage and the cooling air passage.

6. The combustor of claim 5 , wherein the annular air gap is enclosed by the fuel injector body and the annular air gap is radially spaced from the primary fuel passage and the cooling air passage by the fuel injector body.

7. The combustor of claim 1 , wherein a primary fuel output of the primary fuel passage is between 0.1 and 5.0 percent, inclusive, of a total fuel output of the primary fuel passage and the secondary fuel passage.

8. The combustor of claim 1 , wherein the tip surface is disposed downstream of the bulkhead.

9. A combustor for a gas turbine engine, the combustor comprising:

a combustion chamber;

a hood chamber separated from the combustion chamber by a bulkhead, the bulkhead comprising at least one opening extending between the hood chamber and the combustion chamber;

a swirler extending through the at least one opening, the swirler extending from a first axial end to a second axial end, the first axial end spaced upstream of the at least one opening and the second axial end spaced downstream of the at least one opening, the second axial end defining a swirler exit plane at a downstream end of the swirler; and

a fuel injector extending through the swirler, the fuel injector comprising a fuel injector body including an outer radial surface and a tip surface which intersects the outer radial surface, the tip surface located at or downstream of the swirler exit plane, the tip surface extending substantially parallel to the swirler exit plane, the fuel injector comprising:

a primary fuel passage comprising a primary fuel outlet located within the combustion chamber, the primary fuel outlet located in a radial center of the tip surface with respect to a fuel injector center axis;

a secondary fuel passage comprising a plurality of secondary fuel outlets located within the hood chamber, the primary fuel passage configured to inject a hydrogen-based primary fuel directly into the combustion chamber and the secondary fuel passage configured to inject a secondary fuel, different than the hydrogen-based primary fuel, into the combustion chamber; and

a cooling air passage comprising a plurality of air outlets located in the tip surface radially outside of the primary fuel outlet with respect to the fuel injector center axis;

wherein the fuel injector includes an annular air gap disposed within the fuel injector body between the primary fuel passage and the cooling air passage.

10. The combustor of claim 9 , wherein the tip surface extends along the swirler exit plane.

11. The combustor of claim 9 , wherein the tip surface is substantially parallel to the swirler exit plane from the primary fuel outlet to the outer radial surface.

12. The combustor of claim 9 , wherein the annular air gap is enclosed by the fuel injector body and the annular air gap is radially spaced from the primary fuel passage and the cooling air passage by the fuel injector body.

13. A combustor for a gas turbine engine, the combustor comprising:

a combustion chamber;

a hood chamber separated from the combustion chamber by a bulkhead, the bulkhead comprising at least one opening extending between the hood chamber and the combustion chamber;

a swirler extending through the at least one opening and located radially outside of the fuel injector with respect to a fuel injector center axis, the swirler extending from a first axial end to a second axial end, the first axial end located upstream of the at least one opening and the second axial end located at or downstream of the at least one opening, the second axial end defining a swirler opening and a swirler exit plane, the swirler opening having a first diameter; and

a fuel injector extending through the at least one opening, the fuel injector comprising a fuel injector body including an outer radial surface and a tip surface which intersects the outer radial surface, the tip surface located at a downstream end of the fuel injector, the tip surface extending along the swirler exit plane, the tip surface having a second diameter which is greater than forty percent of the first diameter, the fuel injector further comprising a primary fuel passage comprising a primary fuel outlet located in the tip surface, the fuel injector further comprising a secondary fuel passage comprising a plurality of secondary fuel outlets located within the hood chamber, at least a portion of the secondary fuel passage being annular and radially outside of the primary fuel passage, the primary fuel passage configured to inject a hydrogen-based primary fuel directly into the combustion chamber and the secondary fuel passage configured to inject a secondary fuel, different than the hydrogen-based primary fuel, into the combustion chamber.

14. The combustor of claim 13 , wherein the combustion chamber is defined between an inner shell and an outer shell and wherein the bulkhead extends between the inner shell and the outer shell.

15. The combustor of claim 13 , wherein the tip surface extends along the swirler exit plane from the primary fuel outlet to the outer radial surface.

16. The combustor of claim 13 , wherein the fuel injector further comprises a cooling air passage comprising a plurality of air outlets located in the tip surface radially outside of the primary fuel outlet with respect to the fuel injector center axis.

17. The combustor of claim 13 , wherein a primary fuel output of the primary fuel passage is between 0.1 and 5.0 percent, inclusive, of a total fuel output of the primary fuel passage and the secondary fuel passage.

18. The combustor of claim 13 , wherein the fuel injector includes an annular air gap disposed within the fuel injector body between the primary fuel passage and the cooling air passage.

19. The combustor of claim 18 , wherein the annular air gap is enclosed by the fuel injector body and the annular air gap is radially spaced from the primary fuel passage and the cooling air passage by the fuel injector body.