Methods and apparatus for mixing fluid in turbine engines

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

providing at least one heat exchanger assembly including a heat exchanger and a mixer coupled to the at least one heat exchanger and extending downstream from the heat exchanger, wherein the at least one heat exchanger includes an inlet and the mixer includes an inlet that is substantially coaxially aligned with the inlet of the at least one heat exchanger, and wherein the mixer includes a plurality of windows formed therein; and

coupling the at least one heat exchanger assembly within a bypass duct of the engine such that a first portion of bypass air flows above and below the at least one heat exchanger assembly and mixer within the bypass duct, while a second portion of bypass air flows through the at least one heat exchanger, wherein the first and second portions of bypass air communicate at the plurality of windows of the mixer, wherein the at least one heat exchanger assembly is coupled to at least one of an outer engine casing and an inner engine casing of the turbine engine.

2. A method in accordance with claim 1 wherein providing at least one heat exchanger assembly further comprises providing a heat exchanger that includes a hollow body and a plurality of heat exchanger fins within the body.

3. A method in accordance with claim 2 further comprising coupling the mixer to the at least one heat exchanger assembly such that the mixer is in flow communication with a cavity defined within the hollow body.

4. A method in accordance with claim 2 further comprising providing the mixer including an outlet, wherein the outlet has a cross-sectional area that is larger than a cross-sectional area of the inlet of the mixer.

5. A method in accordance with claim 1 wherein coupling the at least one heat exchanger assembly further comprises orienting the at least one heat exchanger assembly within the bypass duct to facilitate reducing pressure losses within the bypass airflow.

6. A method in accordance with claim 1 further comprising coupling the mixer to the at least one heat exchanger assembly such that the inlet of the mixer is coupled to an outlet of the heat exchanger assembly.

7. A method in accordance with claim 1 further comprising coupling the mixer to the at least one heat exchanger assembly, the inlet of the mixer having a cross-sectional area that is smaller than a cross-sectional area of an outlet of the mixer.

8. A heat exchanger assembly for use in a turbine engine, said heat exchanger assembly comprising:

at least one core heat exchanger comprising an inlet; and

a mixer coupled to said at least one core heat exchanger within a bypass duct of the engine such that a first portion of bypass air flows above and below said at least one heat exchanger and mixer within the bypass duct, while a second portion of bypass air flows through the at least one heat exchanger, said mixer extending downstream from said at least one core heat exchanger, said mixer comprising:

an inlet that is substantially coaxially aligned with said inlet of said at least one core heat exchanger; and

a plurality of windows configured to facilitate communication of said first and second portions of bypass air.

9. A heat exchanger assembly in accordance with claim 8 wherein said at least one core heat exchanger further comprises:

an outlet and a hollow body extending between said inlet of said at least one core heat exchanger and said outlet; and

a plurality of heat exchanger fins that extend at least partially through said hollow body between said inlet of said at least one core heat exchanger and said outlet.

10. A heat exchanger assembly in accordance with claim 9 wherein said mixer extends from said at least one core heat exchanger outlet, such that said mixer is in flow communication with a cavity defined within said body.

11. A heat exchanger assembly in accordance with claim 8 wherein said inlet of said mixer has a first cross-sectional area, said mixer further comprises:

an outlet having a second cross-sectional area that is larger than said first cross-sectional area; and

a mixer body extending between said inlet of said mixer and said outlet.

12. A heat exchanger assembly in accordance with claim 8 wherein said mixer facilitates increasing an amount of air entrained within said at least one heat exchanger assembly.

13. A heat exchanger assembly in accordance with claim 11 wherein a portion of said mixer extends divergently downstream from said at least one core heat exchanger.

14. A gas turbine engine comprising:

an outer casing, an inner casing, and a bypass duct defined therebetween, said bypass duct defining an airflow path;

at least one heat exchanger assembly coupled within said bypass duct to at least one of said outer casing and said inner casing, said at least one heat exchanger assembly comprising:

at least one heat exchanger comprising an inlet disposed at least partially within said airflow path; and

a mixer coupled to said at least one heat exchanger within said bypass duct of the engine such that a first portion of bypass air flows above and below said at least one heat exchanger and mixer within said bypass duct, while a second portion of bypass air flows through said at least one heat exchanger, said mixer comprising:

an inlet that is substantially coaxially aligned with said inlet of said at least one heat exchanger; and

a plurality of windows configured to facilitate communication of said first and second portions of bypass air.

15. A gas turbine engine in accordance with claim 14 wherein said at least one heat exchanger assembly comprises:

an outlet and a hollow body extending between said inlet of said at least one heat exchanger and said outlet; and

a plurality of heat exchanger fins extending at least partially through said body between said inlet of said at least one heat exchanger and said outlet.

16. A gas turbine engine in accordance with claim 15 wherein said mixer extends downstream from said outlet and is in flow communication with a cavity defined within said body.

17. A gas turbine engine in accordance with claim 14 wherein said inlet of said mixer has a first cross-sectional area, said mixer further comprises:

an outlet having a second cross-sectional area that is larger than said inlet cross-sectional area; and

a hollow body extending between said inlet of said mixer and said outlet.

18. A gas turbine engine in accordance with claim 15 wherein said mixer facilitates increasing an amount of air entrained within said at least one heat exchanger assembly.

19. A gas turbine engine in accordance with claim 17 wherein a portion of said mixer extends divergently downstream from said at least one heat exchanger.

20. A gas turbine engine in accordance with claim 14 wherein said mixer facilitates reducing pressure losses downstream from said at least one heat exchanger assembly.