Methods and apparatus for operating gas turbine engines

1. A method of operating a gas turbine engine, said method comprising:

channeling cooling air towards a shroud hanger assembly such that the cooling air flows through a screen coupled to a cavity defined in an upstream face of the shroud hanger assembly;

directing air into the cavity through the screen;

directing the cooling air through a plurality of cooling passages extending from the upstream face of the shroud hanger assembly; and

discharging the air from the plurality of cooling passages towards an impingement baffle to facilitate cooling a shroud hanging from the shroud hanger.

2. A method in accordance with claim 1 wherein directing air into the cavity through the screen further comprises:

preventing debris from entering the cavity using the screen.

3. A method in accordance with claim 2 further comprising removing the screen for replacement.

4. A method in accordance with claim 2 further comprising:

forming a plurality of openings within the screen; and

directing air through the screen openings to facilitate cooling the shroud hanger assembly.

5. A method in accordance with claim 4 further comprising:

forming a plurality of pockets within the screen; and

positioning the screen to prevent debris from entering the plurality of cooling passages.

6. A shroud hanger assembly comprising:

a shroud hanger; and

an impingement baffle that is coupled to said shroud hanger, said shroud hanger comprises a cavity, a plurality of cooling passages defined therein and a screen coupled to an upstream face of said shroud hanger, each said cooling passage extends from the upstream face of said shroud hanger through said shroud hanger for channeling cooling air towards said impingement baffle, at least two of said cooling passages are coupled together in flow communication via said cavity.

7. A shroud hanger assembly in accordance with claim 6 wherein said cavity is coupled in flow communication with each of said plurality of cooling passages.

8. A shroud hanger assembly in accordance with claim 6 wherein said impingement baffle comprising orifices extending therethrough facilitates impingement cooling of a shroud radially inward from said shroud hanger assembly wherein cooling air flows through said orifices.

9. A shroud hanger assembly in accordance with claim 6 wherein said screen facilitates preventing debris from restricting air flow to said plurality of cooling passages.

10. A shroud hanger assembly in accordance with claim 6 wherein said screen comprises a plurality of openings extending therethrough and at least one recessed pocket.

11. A shroud hanger assembly in accordance with claim 6 wherein said screen comprises a plurality of openings extending therethrough and at least one convex pocket.

12. A gas turbine engine comprising:

a compressor; and

a turbine assembly coupled downstream said compressor, said turbine assembly comprising a shroud hanger assembly at least partially circumscribing the engine, said shroud hanger assembly comprising:

a shroud hanger; and

an impingement baffle that is coupled to said shroud hanger, said shroud hanger comprises a cavity, a plurality of cooling passages defined therein and a screen coupled to an upstream face of said shroud hanger, each said cooling passage extends from the upstream face of said shroud hanger through said shroud hanger for channeling cooling air towards said impingement baffle, at least two of said cooling passages are coupled together in flow communication via said cavity.

13. A gas turbine engine in accordance with claim 12 wherein said cavity is coupled in flow communication with each of said plurality of cooling passages.

14. A gas turbine engine in accordance with claim 12 wherein said impingement baffle comprising orifices extending therethrough facilitates impingement cooling of a shroud radially inward from said shroud hanger assembly wherein cooling air flows through said orifices.

15. A gas turbine engine in accordance with claim 12 wherein said screen comprises a plurality of openings extending therethrough and at least one recessed pocket.

16. A gas turbine engine in accordance with claim 12 wherein said screen comprises a plurality of openings extending therethrough and at least one convex pocket.

17. A gas turbine engine in accordance with claim 12 wherein said screen facilitates preventing debris from restricting air flow to said plurality of cooling passages.