Component having cooling channel with hourglass cross section

1. A component comprising an interior cooling channel, the cooling channel further comprising:

first and second inner surfaces of respective first and second exterior walls of the component;

first and second side surfaces spanning between the inner surfaces; and

a plurality of turbulators on each of the side surfaces that urge the coolant toward the inner surfaces, wherein a peak in a middle portion of each turbulator defines a waist of the cooling channel;

wherein a transverse section of the channel has an hourglass-shaped profile in which the waist is narrower than a width of each of the first and second inner surfaces; and

wherein an overall direction of a coolant flow in the channel is normal to the hourglass-shaped profile.

2. The component of claim 1 , wherein the first and second inner surfaces are parallel to respective first and second portions of exterior surfaces of the respective exterior walls.

3. The component of claim 1 , wherein the first and second exterior walls are respectively pressure and suction sides of a turbine airfoil.

4. The component of claim 1 , wherein the waist comprises a width of 80% or less than the width of at least one of the inner surfaces.

5. The component of claim 1 , wherein the each of the turbulators comprises two surfaces that converge toward the waist, wherein each of the converging surfaces has a taper angle in the profile of at least −1 degrees toward the waist relative to a straight line between corresponding ends of the two side surfaces.

6. The component of claim 1 , further comprising a plurality of parallel fins with a transverse height profile that is convex across a width of at least one of the inner surfaces, wherein the fins are oriented with the coolant flow direction.

7. The component of claim 1 , wherein each turbulator comprises a convex upstream side.

8. The component of claim 1 , wherein each turbulator comprises a convex upstream side and a straight downstream side.

9. The component of claim 1 , further comprising:

a plurality of parallel fins oriented with the coolant flow direction on each of the inner surfaces, wherein a height profile that transversely connects adjacent peaks of the fins is convex across a width of each of the inner surfaces; and

wherein each turbulator comprises a convex upstream side.

10. The component of claim 1 , wherein the each of the turbulators comprises two surfaces converging toward the waist, wherein each of the converging surfaces has a taper angle in the profile of −2 to −5 degrees relative to a straight line between corresponding ends of the two interior side surfaces.

11. A turbine airfoil component comprising a coolant exit channel in a trailing edge portion, the coolant exit channel further comprising:

first and second near-wall inner surfaces parallel to respective first and second exterior surfaces of the trailing edge portion;

two interior side surfaces between the near-wall inner surfaces that converge to a waist at an intermediate position between the first and second near-wall inner surfaces forming an hourglass-shaped transverse profile of the channel;

a plurality of fins on each of the near-wall inner surfaces, wherein the fins are aligned with an overall flow direction of the coolant exit channel, and the plurality of fins has a convex height profile across the width of each near-wall inner surface; and

a plurality of turbulators on each of the side surfaces that urge the coolant flow toward the near-wall inner surfaces, wherein a peak in a middle portion of each turbulator defines the waist of the cooling channel.

12. The component of claim 11 , wherein each turbulator comprises a convex upstream side.

13. The component of claim 11 , wherein each turbulator comprises a convex upstream side and a straight downstream side.

14. A component comprising a cooling channel, the cooling channel further comprising:

a first inner surface parallel to a first exterior surface of the component and a tapered transverse sectional profile that is wider at the first inner surface and narrower away from the first inner surface;

a second inner surface parallel to a second exterior surface of the component;

first and second interior side surfaces spanning between the first and second inner surfaces;

a plurality of turbulators on each of the interior side surfaces of the channel that urge the coolant flow toward the inner surfaces, wherein a peak in a middle portion of each turbulator defines a waist of the cooling channel that is narrower than a width of either of the first and second inner surfaces;

and a plurality of parallel fins with a transverse height profile that is convex across a width of the inner surface, wherein the fins are oriented with a direction of a coolant flow in the channel;

wherein the cooling channel is effective to urge the coolant flow therein toward corners of the cooling channel.

15. The component of claim 14 , wherein each turbulator comprises a convex upstream side.

16. The component of claim 14 , wherein each turbulator comprises a convex upstream side and a straight downstream side.