Airfoil cooling

1. An airfoil comprising:

an external airfoil surface;

an airfoil body comprising an external wall structure and an internal wall structure, wherein the external airfoil surface is adjacent the external wall structure, wherein the internal wall structure is disposed inward from the external wall structure relative to the external airfoil surface, wherein the airfoil body defines:

a skin core at least partially defined by a first section of the external wall structure and a first section of the internal wall structure; and

an embedded core entirely defined by the internal wall structure, wherein an embedded core heat transfer augmentation feature is formed within the embedded core on an embedded core surface of the first section of the internal wall structure.

2. The airfoil of claim 1 , wherein a skin core heat transfer augmentation feature is formed within the skin core on a skin core surface of the first section of the external wall structure.

3. The airfoil of claim 1 , wherein the embedded core heat transfer augmentation feature is disposed between the skin core and the embedded core.

4. The airfoil of claim 1 , wherein the skin core extends along at least a portion of a leading edge of the airfoil.

5. The airfoil of claim 4 , wherein the skin core is a first skin core, wherein the airfoil body defines a second skin core disposed adjacent the first skin core.

6. The airfoil of claim 5 , wherein the second skin core is at least partially defined by a second section of the external wall structure and the first section of the internal wall structure.

7. The airfoil of claim 6 , wherein the second skin core extends along at least a portion of a pressure side of the airfoil.

8. The airfoil of claim 6 , wherein the airfoil body defines a third skin core disposed adjacent the first skin core, wherein the third skin core is at least partially defined by a third section of the external wall structure and the first section of the internal wall structure.

9. The airfoil of claim 8 , wherein the third skin core extends along at least a portion of a suction side of the airfoil.

10. The airfoil of claim 8 , wherein the first skin core, the second skin core, and the third skin core are disposed around the embedded core.

11. The airfoil of claim 1 , wherein the external airfoil surface abuts the external wall structure.

12. The airfoil of claim 1 , wherein the embedded core heat transfer augmentation feature comprises a plurality of embedded core heat transfer augmentation features.

13. The airfoil of claim 12 , wherein the embedded core heat transfer augmentation features comprise an array of trip strips.

14. An airfoil comprising:

an external airfoil surface;

an airfoil body comprising an external wall structure and an internal wall structure, wherein the external airfoil surface is adjacent the external wall structure, wherein the internal wall structure is disposed inward from the external wall structure relative to the external airfoil surface, wherein the airfoil body defines:

a first skin core at least partially defined by a first section of the external wall structure and a first section of the internal wall structure, wherein a skin core heat transfer augmentation feature is formed within the first skin core on a skin core surface of the first section of the external wall structure, wherein the first skin core extends along at least a portion of a leading edge of the airfoil;

a second skin core disposed adjacent the first skin core, wherein the second skin core is at least partially defined by a second section of the external wall structure and the first section of the internal wall structure, wherein the second skin core extends along at least a portion of a pressure side of the airfoil;

a third skin core disposed adjacent the first skin core, wherein the third skin core is at least partially defined by a third section of the external wall structure and the first section of the internal wall structure, wherein the third skin core extends along at least a portion of a suction side of the airfoil; and

an embedded core entirely defined by the internal wall structure, wherein an embedded core heat transfer augmentation feature is formed within the embedded core on an embedded core surface of the first section of the internal wall structure.

15. A gas turbine engine, comprising:

a compressor configured to rotate about an axis and compress a gas;

a combustor aft of the compressor and configured to combust the gas;

a turbine section aft of the combustor and configured to extract energy from the combusted gas, wherein the turbine section comprises an airfoil configured to rotate about the axis, wherein the airfoil comprises an external airfoil surface and an airfoil body, wherein the airfoil body comprises an external wall structure and an internal wall structure, wherein the external airfoil surface is adjacent the external wall structure, wherein the internal wall structure is disposed inward from the external wall structure relative to the external airfoil surface, wherein the airfoil body defines:

a skin core at least partially defined by a first section of the external wall structure and a first section of the internal wall structure; and

an embedded core entirely defined the internal wall structure, wherein an embedded core heat transfer augmentation feature is formed within the embedded core on an embedded core surface of the first section of the internal wall structure.

16. The gas turbine engine of claim 15 , wherein a skin core heat transfer augmentation feature is formed within the skin core on a skin core surface of the first section of the external wall structure.

17. The gas turbine engine of claim 16 , wherein the embedded core heat transfer augmentation feature is disposed between the skin core and the embedded core.