Additively manufactured permeable barrier layer and method of manufacture

1. A vessel comprising:

a first portion that is non-permeable to a fluid, the first potion defining at least one exterior wall defining an exterior container;

a second portion that is non-permeable to the fluid, the second portion defining at least one interior wall defining an interior container encapsulated by the exterior container; and

a third portion that is permeable to the fluid, the third portion being positioned between the at least one exterior wall and the at least one interior wall and having a thickness extending from the exterior wall to the interior wall approximately equal to a laser diameter used to form the third portion, the third portion being integrally formed with the first portion and the second portion and comprising a porous structure with non-uniform connected porosity

wherein the porous structure comprises a plurality of dense regions having a porosity of less than 0.5 percent.

2. The vessel of claim 1 , wherein the vessel is a heat exchanger comprising a plurality of sections disposed in a stacked arrangement, wherein each section comprises a portion of the interior container and a portion of the exterior container.

3. The vessel of claim 1 , wherein the third portion is configured to transfer thermal energy between the exterior wall and the interior wall.

4. The vessel of claim 1 , wherein the third portion is configured to transfer vibrational loads between the exterior wall and the interior wall.

5. The vessel of claim 1 , wherein the third portion forms a flow path envelope surrounding the interior container.

6. The vessel of claim 1 , wherein the third portion is in fluid communication with a drain port of the vessel.

7. The vessel of claim 1 , wherein dense regions of the plurality of dense regions are arranged in a pattern.

8. The vessel of claim 7 , wherein the dense regions are disposed orthogonally to the exterior wall and the interior wall.

9. The vessel of claim 8 , wherein the dense regions are rectangular in shape.

10. The vessel of claim 1 , wherein the third portion comprises fused powder particles.

11. A heat exchanger comprising:

an exterior container formed by an exterior wall that is non-permeable to a fluid;

an interior container formed by an interior wall that is non-permeable to a fluid, wherein the interior container is disposed within the exterior container such that the exterior container encapsulates the interior container;

a plurality of sections disposed in a stacked arrangement, wherein each section comprises a portion of the interior container and a portion of the exterior container; and

a permeable portion disposed between and formed integrally with the exterior wall and the interior wall and having a thickness extending from the exterior wall to the interior wall approximately equal to a laser diameter used to form the permeable portion, wherein the permeable portion comprises a porous structure having non-uniform connected porosity;

wherein the permeable portion comprises a plurality of dense regions having a porosity of less than 0.5 percent.

12. The heat exchanger of claim 11 , and further comprising:

a plurality of connections extending between sections of the plurality of sections, wherein each connection of the plurality of connections fluidly connects adjacent sections of the plurality of sections; and

a drain port disposed in the exterior container, wherein the drain port is in fluid communication with the plurality of connections and with the permeable portion.

13. The pressure vessel of claim 11 , wherein dense regions of the plurality of dense regions are arranged in a pattern.

14. The heat exchanger of claim 11 , wherein the permeable portion comprises fused powder particles.