System for cooling and purging exhaust section of gas turbine engine

1. A system, comprising:

a turbine exhaust strut configured to provide a bi-directional airflow, wherein the turbine exhaust strut comprises:

a first portion comprising an inner body having a first flow passage configured to flow a fluid in a first direction between inner and outer exhaust walls of a turbine exhaust section; and

a second portion comprising an outer body having a second flow passage configured to flow the fluid in a second direction between the inner and outer exhaust walls of the turbine exhaust section, wherein the first and second directions are opposite from one another and the outer body surrounds the inner body.

2. The system of claim 1 , wherein the first flow direction is oriented from the outer exhaust wall to the inner exhaust wall, and the second flow direction is oriented from the inner exhaust wall to the outer exhaust wall.

3. The system of claim 1 , wherein the first flow direction is oriented from the inner exhaust wall to the outer exhaust wall, and the second flow direction is oriented from the outer exhaust wall to the inner exhaust wall.

4. The system of claim 1 , wherein the inner body comprises a third flow passage separated from the first flow passage, and the third flow passage is configured to flow the fluid in the first direction or the second direction.

5. The system of claim 1 , wherein the outer body comprises a fourth flow passage separated from the second flow passage, and the fourth flow passage is configured to flow the fluid in the first direction or the second direction.

6. The system of claim 1 , wherein the inner body comprises a load bearing structural support, and the outer body is non-load bearing.

7. The system of claim 1 , wherein the first flow passage is configured to flow the fluid into a first cavity between the inner exhaust wall and the rotation axis, and the second flow passage is configured to flow the fluid from the first cavity to a second cavity between the outer exhaust wall and an outer casing of the turbine exhaust section.

8. The system of claim 7 , comprising the turbine exhaust section having the inner exhaust wall, the outer exhaust wall, and the outer casing.

9. The system of claim 8 , wherein the first cavity comprises a bearing assembly, a lubricant passage, or a combination thereof.

10. The system of claim 8 , wherein the inner exhaust wall or the outer exhaust wall comprises a plurality of openings configured to flow the fluid into the exhaust flow path.

11. The system of claim 10 , wherein each opening of the plurality of openings comprises a removable insert.

12. The system of claim 8 , comprising a single blower configured to circulate the fluid through the first and second flow passages.

13. A system, comprising:

a turbine exhaust section, comprising:

an exhaust flow path;

an outer structure comprising an outer exhaust wall disposed along the exhaust flow path;

an inner structure comprising an inner exhaust wall disposed along the exhaust flow path, and an inner cavity disposed between the inner exhaust wall and a rotational axis of a turbine;

a bearing assembly disposed in the inner cavity;

a lubrication passage disposed in the inner cavity; and

a strut extending between the outer structure and the inner structure, wherein the strut comprises a first flow passage configured to flow a fluid through the inner cavity;

wherein the inner cavity comprises a first cavity portion disposed along the bearing assembly, a second cavity portion disposed along the lubrication passage, and a third cavity portion disposed along a downstream end portion of the inner structure.

14. The system of claim 13 , comprising a first baffle disposed between the first cavity and the third cavity, and a second baffle disposed between the second cavity and the third cavity.

15. The system of claim 13 , wherein the outer structure comprises an outer casing and an outer cavity disposed between the outer exhaust wall and the outer casing, and the strut comprises a second flow passage configured to flow the fluid from the inner cavity to the outer cavity.

16. A system, comprising:

a turbine section, and

an exhaust section coupled to the turbine section, comprising:

an exhaust flow path;

an outer structure comprising an outer exhaust wall disposed along the exhaust flow path, an outer casing, and an outer cavity disposed between the outer exhaust wall and the outer casing;

an inner structure comprising an inner exhaust wall disposed along the exhaust flow path, and an inner cavity disposed between the inner exhaust wall and a rotational axis of a turbine;

a strut extending between the inner and outer structures, comprising:

an inner body with a first flow passage configured to flow a fluid between the outer exhaust wall and the inner exhaust wall; and

an outer body with a second flow passage configured to flow the fluid between the outer exhaust wall and the inner exhaust wall, wherein the outer body surrounds the inner body.