WE CLAIM:
1. A heat exchanger (10) comprising:
an input cavity (20) defined by inlet cavity walls (21);
a heat exchanger portion (22) in fluid communication with the input cavity (20) and defined between a first side (34) and a second side (36), wherein a plurality of baffles (28) are positioned within the heat exchanger portion (22); and
an outlet cavity (24) in fluid communication with the heat exchanger portion (22) and defined by outlet cavity walls (25),
wherein the heat exchanger portion (22) comprises:
a plurality of first fluid paths (26) defined between the baffles (28) and extending from the input cavity (20) to the outlet cavity (24), and
a plurality of tubes (42) extending through the heat exchanger portion (22) from the first side (34) to the second side (36), wherein each tube (42) extends through the baffles (28) so as to define a second fluid path (32) through the heat exchanger portion (22).
2. The heat exchanger (10) as claimed in claim 1, wherein the first fluid paths (26) are oriented in a cross-flow arrangement with respect to the second flow paths (32).
3. The heat exchanger (10) as claimed in claim 1, wherein at least one flow turbulating element (46) is positioned on an external surface of a tube (42), wherein at least one flow turbulating element (46) is positioned on an internal surface of a tube (42), or both.
4. The heat exchanger (10) as claimed in claim 1, wherein each tube (42) defines an inlet flow cross-section area at the first side (34) and an outlet flow cross-section area at the second side (36), wherein at least one tube (42) varies in its cross-section area continuously from the first side (34) to the second side (34) of the heat exchanger portion (22).
5. The heat exchanger (10) as claimed in claim 1, wherein each tube (42) defines an inlet flow cross-section area at the first side (34) and an outlet flow cross-section area at the second side (36), wherein the inlet flow cross-section area is a different size than the outlet flow cross-section area.

6. The heat exchanger (10) as claimed in claim 1, wherein a plurality of structural elements (78) are positioned on at least one of the inlet cavity walls (21) and the outlet cavity walls (25).
7. The heat exchanger (10) as claimed in claim 1, comprising a plurality of heat exchanger portions (22) between the input cavity (20) and the output cavity (24), wherein the plurality of heat exchanger portions (20) are serially connected to each other with respect to the first flow path (26).
8. The heat exchanger (10) as claimed in claim 1, wherein the input cavity (20), the heat exchanger portion (22), and the outlet cavity (24) define an integrated component (50) formed via additive manufacturing.
9. The heat exchanger (10) as claimed in claim 1, further comprising:
a cooling input cavity (92) positioned on the first side (34) of the heat
exchanger portion (22); and
a cooling output cavity (96) positioned on the second side (36) of the heat exchanger portion (22), wherein the plurality of tubes (42) extend through the heat exchanger portion (22) from the cooling input cavity (96) positioned on the first side (34) to the cooling output cavity (96) positioned on the second side (36).
10. The heat exchanger (10) as claimed in claim 1, wherein the baffles
(28) define the flow cross-section areas of the first fluid paths (26) within the heat
exchanger portion (22), wherein the flow cross-section areas vary in the first fluid
paths from the inlet cavity (20) to the outlet cavity (24).