Cooled turbine airfoil structures

An air-cooled turbine blade having an airfoil shape, comprising:

• a multi-walled convex suction side wall comprising a convex-side outer wall and a convex-side inner wall, wherein a space between the convex-side outer wall and the convex-side inner wall defines a convex-side cooling air passage;
• a multi-walled concave pressure side wall comprising a concave-side outer wall and a concave-side inner wall, wherein a space between the concave-side outer wall and the concave-side inner wall defines a concave-side cooling air passage, each of the convex-side and concave side inner walls including an interior surface that defines an interior with the blade;
• a suction side flow circuit formed within the convex-side cooling air passage;
• a pressure side flow circuit formed within the concave-side cooling air passage;
• and
• a plurality of pins at a trailing edge of the blade and positioned aft of the suction side and pressure side flow circuits,
• wherein the turbine blade comprises, in a mid-section extending from the suction side flow circuit and the pressure side flow circuit to the plurality of pins at the trailing edge, a generally Y-shaped cross-section defined with a first end of the Y-shape extending from the suction side flow circuit to the plurality of pins and a second end of the Y-shape extending from the pressure side flow circuit to the plurality of pins, an open space being present between the first and second ends of the Y-shape in the mid-section, and wherein the pressure side flow circuit comprises a plurality of pins positioned on the concave side outer wall of the pressure side flow circuit extending towards, but not in contact with, the concave side inner wall of the pressure side flow circuit.