System of supporting turbine diffuser outlet

1. A system comprising:

a diffuser section comprising an outer barrel, an inner barrel, a seal interface, and an aft plate, wherein the outer barrel and the inner barrel are disposed about a turbine axis, and the diffuser section is configured to receive an exhaust gas from a gas turbine;

wherein the seal interface is disposed at a downstream end of the inner barrel between the inner barrel and the aft plate, wherein the downstream end of the inner barrel extends transverse to the turbine axis and the seal interface comprises:

a first circumferential groove configured to receive a portion of the aft plate transverse to the turbine axis, wherein the first circumferential groove opens in a first direction transverse to the turbine axis.

2. The system of claim 1 , comprising an exhaust plenum disposed downstream of the diffuser section, wherein the exhaust plenum is configured to receive the exhaust gas from the diffuser section, and the seal interface is configured to isolate the exhaust plenum from a bearing tunnel disposed within the inner barrel.

3. The system of claim 2 , comprising a second flexible seal disposed at an upstream end of the outer barrel, wherein the second flexible seal is configured to isolate the exhaust plenum from a cooling channel disposed along a turbine outlet upstream of the outer barrel.

4. The system of claim 1 , wherein the aft plate comprises a plurality of stress relieving features at an upstream end portion proximate the seal interface.

5. The system of claim 4 , wherein the aft plate comprises a plurality of circumferential segments, wherein a set of the plurality of stress relieving features is disposed along a joint between circumferential segments of the aft plate.

6. The system of claim 1 , wherein the aft plate is configured to interface with a root of the first circumferential groove at a 12 o'clock position of the seal interface.

7. The system of claim 6 , wherein the aft plate is offset from the root of the first circumferential groove at a 6 o'clock position of the seal interface, wherein the 6 o'clock position is opposite the 12 o'clock position relative to the turbine axis.

8. The system of claim 1 , wherein the seal interface is mechanically coupled to the downstream end of the inner barrel.

9. A system comprising:

a diffuser section comprising an outer barrel, an inner barrel, a seal interface, and an aft plate, wherein the outer barrel and the inner barrel are disposed about a turbine axis, and the diffuser section is configured to receive an exhaust gas from a gas turbine;

an exhaust plenum disposed downstream of the diffuser section, wherein the exhaust plenum is configured to receive the exhaust gas from the diffuser section; wherein the seal interface is disposed at a downstream end of the inner barrel between the inner barrel and the aft plate, wherein the aft plate comprises a plurality of circumferential segments, the downstream end of the inner barrel extends transverse to the turbine axis, and the seal interface comprises:

a first circumferential groove configured to receive a portion of the aft plate transverse to the turbine axis, wherein the first circumferential groove opens in a first direction transverse to the turbine axis.

10. The system of claim 9 , wherein a plurality of stress relieving features are disposed within the aft plate along a plurality of joints between the plurality of circumferential segments upstream from the seal interface.

11. The system of claim 10 , wherein the plurality of stress relieving features are circular, heart-shaped, bean-shaped, or any combination thereof.

12. The system of claim 9 , wherein a plurality of joints between the plurality of circumferential segments are welded joints.

13. The system of claim 9 , wherein the aft plate is configured to interface with a root of the first circumferential groove at a 12 o'clock position of the seal interface.

14. The system of claim 13 , wherein the aft plate is offset from the root of the first circumferential groove at a 6 o'clock position of the seal interface, wherein the 6 o'clock position is opposite the 12 o'clock position relative to the turbine axis.

15. The system of claim 9 , comprising a second flexible seal disposed at an upstream end of the outer barrel, wherein the second flexible seal is configured to isolate the exhaust plenum from a cooling channel disposed along a turbine outlet upstream of the outer barrel.

16. A method, comprising:

inserting a plurality of aft plate segments in a radial direction towards a turbine axis into a first circumferential groove of a first seal interface on an inner barrel of a diffuser section of a gas turbine;

interfacing the plurality of aft plates with a root of the first seal interface at a 12 o'clock position prior to joining the aft plates, wherein a 6 o'clock position of the aft plate is offset from the root; and

joining the plurality of aft plate segments to one another, wherein the aft plate segments comprise a plurality of stress relieving features at an end portion proximate to a seal interface.

17. The method of claim 16 , comprising assembling an exhaust plenum about the plurality of aft plate segments and the first seal interface.

18. The method of claim 16 , wherein joining comprises welding, brazing, fusing, fastening, or any combination thereof.

19. The method of claim 16 , wherein interfacing the plurality of aft plates with the root of the first seal interface comprises sliding the aft plate towards the root such that the aft plate moves within the first circumferential groove.

20. The method of claim 16 , comprising inserting a flexible seal into a second circumferential groove of a second seal interface.