Additively manufactured fin slots for thermal growth

1. A core arrangement for a heat exchanger comprising:

a first core layer comprising:

a first upstream end;

a first downstream end;

a first parting sheet;

a second parting sheet parallel to the first parting sheet; and

a plurality of adjacent fins disposed between the first and second parting sheets; and

wherein each of the plurality of fins extends from a surface of the first parting sheet to a surface of the second parting sheet, and longitudinally between the first upstream end and the first downstream end;

an elongate internal slot in at least one of the plurality of adjacent fins; the elongate internal slot characterized by a length corresponding to the longitudinal direction of the fins of the first core layer, wherein the elongate internal slot is assymetric such that it has a first height at one region and a second, greater height at a second region, each measured perpendicularly to the length;

wherein the length is greater than each of the first and second height;

wherein the plurality of fins are further laterally arranged to define a plurality of first fluid passages; and

wherein the elongate internal slot is positioned away from the first upstream end and the first downstream end.

2. The core arrangement of claim 1 , and further comprising:

a second core layer adjacent to the first core layer, the second core layer comprising:

a second upstream end either perpendicular to, or parallel to and oppositely disposed from the first upstream end;

a second downstream end either perpendicular to, or parallel to and oppositely disposed from the first downstream end;

a third parting sheet parallel to the second parting sheet; and

a plurality of adjacent fins disposed between the second and third parting sheets;

wherein each of the plurality of fins extends from a surface of the second parting sheet to a surface of the third parting sheet, and longitudinally between the second upstream end and the second downstream end; and

wherein the plurality of fins are further laterally arranged to define a plurality of second fluid passages.

3. The core arrangement of claim 2 , wherein the geometry of the internal slot is further characterized by a curved edge.

4. The core arrangement of claim 2 , wherein the first core layer further comprises a second elongate internal slot in a second of the plurality of adjacent fins.

5. The core arrangement of claim 4 , wherein the first fin is adjacent to the second fin.

6. The core arrangement of claim 5 , wherein the geometry of the elongate internal slot of the first fin is different from the geometry of the second elongate internal slot of the second fin.

7. The core arrangement of claim 4 , wherein the first fin and the second fin are non-adjacent.

8. The core arrangement of claim 6 and further comprising: an un-slotted fin disposed between the first fin and the second fin.

9. The core arrangement of claim 4 , wherein a longitudinal position of the internal slot of the first fin is different from a longitudinal position of the internal slot of the second fin.

10. The core arrangement of claim 2 , wherein the first core layer and the second core layer are formed using an additive manufacturing process.

11. The core arrangement of claim 10 , wherein the additive manufacturing process is a powder bed fusion technique.

12. A heat exchanger comprising:

a core arrangement comprising:

a first core layer comprising:

a first upstream end;

a first downstream end;

a first parting sheet;

a second parting sheet parallel to the first parting sheet; and

a plurality of adjacent fins disposed between the first and second parting sheets; and

wherein each of the plurality of fins extends from a surface of the first parting sheet to a surface of the second parting sheet, and longitudinally between the first upstream end and the first downstream end;

an elongate internal slot in at least one of the plurality of adjacent fins; the elongate internal slot characterized by a length corresponding to the longitudinal direction of the fins of the first core layer, wherein the elongate internal slot is assymetric such that it has a first height at one region and a second, greater height at a second region, each measured perpendicularly to the length;

wherein the length is greater than each of the first and second height;

wherein the plurality of fins are further laterally arranged to define a plurality of first fluid passages; and

wherein the elongate internal slot positioned away from the first upstream end and the first downstream end.

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

a second core layer adjacent to the first core layer, the second core layer comprising:

a second upstream end either perpendicular to, or parallel to and oppositely disposed from the first upstream end;

a second downstream end either perpendicular to, or parallel to and oppositely disposed from the first downstream end by at least ninety degrees;

a third parting sheet parallel to the second parting sheet; and

a plurality of adjacent fins disposed between the second and third parting sheets;

wherein each of the plurality of fins extends from a surface of the second parting sheet to a surface of the third parting sheet, and longitudinally between the second upstream end and the second downstream end; and

wherein the plurality of fins are further laterally arranged to define a plurality of second fluid passages.

14. The heat exchanger of claim 13 , wherein the geometry of the internal slot is further characterized by a curved edge.