Combustor and method for purging a combustor

1. A combustor, comprising:

a. an end cap, wherein the end cap includes a first surface and a second surface downstream from the first surface;

b. a shroud that circumferentially surrounds at least a portion of the first and second surfaces;

c. a plate that extends radially within the shroud, the plate defining a plurality of plate passages that extend axially therethrough;

d. a plurality of tubes that extend through the plate and the first and second surfaces, wherein each tube having an inlet and an outer and extend through a corresponding plate passage of the plurality of plate passage;

e. a radial gap defined between one or more of the plurality of tubes and the plate at a corresponding plate passage; and

f. a first purge port that extends through a wall one or more of the plurality of tubes, wherein the first purge port is radially aligned with the plate facing the corresponding plate passage.

2. The combustor of claim 1 , wherein the plate at least partially defines a first diluent plenum between the plate and the first surface.

3. The combustor as in claim 1 , further comprising a first diluent port that extends through the shroud upstream from the plate.

4. The combustor of claim 1 , wherein the plate at least partially defines a second diluent plenum between the plate and the second surface.

5. The combustor as in claim 1 , further comprising a second diluent port that extends through the shroud downstream from the plate.

6. The combustor of claim 1 , further comprising a second purge port located upstream of the plate.

7. The combustor of claim 1 , further comprising a first diluent port upstream of the plate and a second diluent port downstream of the plate.

8. The combustor of claim 1 , further comprising a fuel plenum surrounding the plurality of tubes, wherein the fuel plenum is located upstream of the plate and at least partially circumferentially surrounded by the shroud.

9. A combustor, comprising:

a. an end cap;

b. a plurality of tubes that extend through the end cap and provide fluid communication through the end cap, each tube having an inlet and outlet;

c. a plate that extends radially inside the end cap, the plate defining a plurality of plate passages that extend axially therethrough;

d. a radial gap defined between one or more of the plurality of tubes and the plate at a corresponding plate passage; and

e. a first purge port between the plate and one or more of the plurality of tubes, wherein the first purge port extends through a wall and provides fluid communication into the one or more of the plurality of tubes, wherein the first purge port is radially aligned with the plate facing the corresponding plate passage and the radial gap.

10. The combustor of claim 9 , further comprising a second purge port located upstream of the plate.

11. The combustor of claim 10 , further comprising a third purge port located downstream of the plate.

12. The combustor of claim 9 , further comprising a fuel plenum surrounding the plurality of tubes, wherein the fuel plenum is located upstream of the plate.

13. The combustor of claim 9 , wherein the end cap includes a first surface axially separated from a downstream second surface.

14. The combustor of claim 13 , further comprising a shroud extending axially from the end cap first surface to the end cap second surface, wherein the shroud at least partially surrounds the plurality of tubes.

15. The combustor of claim 14 , wherein the plate at least partially defines a first diluent plenum between the plate and the first surface.

16. The combustor of claim 14 , wherein the plate at least partially defines a second diluent plenum between the plate and the second surface.

17. The combustor of claim 14 , further comprising a first diluent port upstream of the plate and a second diluent port downstream of the plate.