Additively manufactured heat exchanger

1. An assembly comprising a heat exchanger, a component, and a cowl at least partially surrounding the component, the cowl defining at least one peripheral gap and at least one cowl plenum, the heat exchanger comprising:

a housing defining a heat exchange plenum for receiving a first heat exchange fluid;

a plurality of heat exchange tubes passing through the heat exchange plenum, the plurality of heat exchange tubes being fluidly isolated from the heat exchange plenum for receiving a second heat exchange fluid;

an inlet manifold defining an inlet plenum in fluid communication with the heat exchange plenum for receiving the first heat exchange fluid;

a discharge manifold defining a discharge plenum in fluid communication with the heat exchange plenum, the discharge manifold being positioned within and bridging the at least one peripheral gap of the cowl;

a fluid outlet defined by the discharge manifold, the fluid outlet providing fluid communication between the discharge plenum and the at least one cowl plenum; and

an impingement baffle at least partially defining the discharge manifold and defining an impingement gap between the impingement baffle and the component, the impingement baffle defining a plurality of cooling holes through which the first heat exchange fluid is impinged onto the component.

2. The assembly of claim 1 , wherein the discharge manifold defines an exhaust port providing fluid communication between the impingement gap and an ambient environment.

3. The assembly of claim 1 , wherein the inlet plenum, the heat exchange plenum, and the discharge plenum extend substantially along a first direction, and wherein the plurality of heat exchange tubes pass through heat exchange plenum substantially along a second direction perpendicular to the first direction.

4. The assembly of claim 3 , wherein the heat exchange tubes pass through heat exchange plenum in a serpentine pattern between a first side of the housing proximate the discharge manifold and a second side of the housing proximate the inlet manifold.

5. The assembly of claim 1 , wherein the housing comprises a plurality of walls, at least one of the plurality of walls being contoured to maintain a substantially constant gap between the wall and the heat exchange tubes within the heat exchange plenum.

6. The assembly of claim 1 , wherein one or more support struts extend between and connect adjacent tubes of the plurality of heat exchange tubes.

7. The assembly of claim 1 , wherein the heat exchanger comprises:

one or more flow splitters positioned within the inlet plenum and extending between a cooling air inlet and the plurality of heat exchange tubes.

8. The assembly of claim 1 , wherein the component is annular and the cowl is semi-annular and is joined with the heat exchanger to surround the component.

9. The assembly of claim 1 , wherein the heat exchanger is a first heat exchanger, the heat exchanger further comprising a second heat exchanger, and wherein the cowl comprises a first half and a second half, the first half and the second half being joined by the first heat exchanger and the second heat exchanger.

10. The assembly of claim 1 , wherein the heat exchanger is an air-air heat exchanger configured for receiving a cool air stream within the heat exchanger plenum and a hot air stream within the plurality of heat exchange tubes.

11. The assembly of claim 1 , wherein the cowl defines a plurality of cowl cooling holes providing fluid communication between the at least one cowl plenum and a cowl impingement gap defined between the component and the cowl.

12. The assembly of claim 1 , wherein the component is a power turbine of a gas turbine engine and the cowl is a power turbine cowl, and wherein the inlet plenum is in fluid communication with an ejector assembly of the gas turbine engine that provides a mixture of bleed air from a compressor section and ambient air, and wherein the heat exchange tubes are in fluid communication with a B-sump heat exchanger of the gas turbine engine.

13. The assembly of claim 1 , wherein the heat exchanger comprises a plurality of layers formed by:

depositing a layer of additive material on a bed of an additive manufacturing machine; and

selectively directing energy from an energy source onto the layer of additive material to fuse a portion of the additive material.

14. The assembly of claim 1 , wherein the housing, the heat exchange tubes, the inlet manifold, the discharge manifold, and the impingement baffle are integrally formed as a single monolithic component.

15. A method of manufacturing a heat exchanger, the method comprising:

depositing a layer of additive material on a bed of an additive manufacturing machine; and

selectively directing energy from an energy source onto the layer of additive material to fuse a portion of the additive material and form the heat exchanger for cooling a component, and a cowl at least partially surrounding the component, the cowl defining at least one peripheral gap and at least one cowl plenum, the heat exchanger comprising:

a housing defining a heat exchange plenum;

a plurality of heat exchange tubes passing through the heat exchange plenum; and

a discharge manifold defining a discharge plenum in fluid communication with the heat exchange plenum, the discharge manifold being positioned within and bridging the at least one peripheral gap of the cowl;

an inlet manifold defining an inlet plenum in fluid communication with the heat exchange plenum;

a fluid outlet defined by the discharge manifold, the fluid outlet providing fluid communication between the discharge plenum and the at least one cowl plenum; and

an impingement baffle at least partially defining the discharge manifold and defining an impingement gap between the impingement baffle and the component, the impingement baffle defining a plurality of cooling holes.

16. The method of claim 15 , wherein the discharge manifold defines an exhaust port providing fluid communication between the impingement gap and an ambient environment.

17. The method of claim 15 , wherein the inlet plenum, the heat exchange plenum, and the discharge plenum extend substantially along a first direction, and wherein the plurality of heat exchange tubes pass through heat exchange plenum substantially along a second direction perpendicular to the first direction, and wherein the heat exchange tubes pass through heat exchange plenum in a serpentine pattern between a first side of the housing proximate the discharge manifold and a second side of the housing proximate the inlet manifold.

18. The method of claim 15 , further comprising:

forming one or more flow splitters, the one or more flow splitters being positioned within the inlet plenum and extending between a cooling air inlet and the plurality of heat exchange tubes.

19. An assembly comprising:

an annular casing;

a cowl assembly spaced apart from the annular casing to define an impingement gap, the cowl assembly defining a cowl plenum, a plurality of cowl cooling holes providing fluid communication between the cowl plenum and the impingement gap, and a peripheral gap;

a heat exchanger positioned within the peripheral gap of the cowl assembly, the heat exchanger comprising:

a housing defining a heat exchange plenum;

a plurality of heat exchange tubes passing through the heat exchange plenum;

an inlet manifold defining an inlet plenum in fluid communication with the heat exchange plenum;

a discharge manifold defining a discharge plenum in fluid communication with the heat exchange plenum, the discharge manifold being positioned within and bridging the peripheral gap of the cowl assembly;

a fluid outlet defined by the discharge manifold, the fluid outlet providing fluid communication between the discharge plenum and the cowl plenum; and

an impingement baffle at least partially defining the discharge manifold and defining the impingement gap between the impingement baffle and the annular casing, the impingement baffle defining a plurality of cooling holes.