Serpentine cooling circuit with T-shaped partitions in a turbine airfoil

A turbine airfoil with a radial span, comprising:

• a serpentine cooling circuit starting from a radial feed channel and progressing axially in alternating tangential directions between partitions that define a series of interconnected radial channels that progresses axially through the airfoil;
• wherein
• at least one of the partitions comprises a T-shaped transverse section;
• each T-shaped section comprises a base portion that extends normally from a suction side wall or a pressure side wall of the airfoil;
• each T-shaped section further comprises a crossing portion that is parallel to, and is not directly attached to, the pressure side wall or suction side wall that is opposite the base portion of said each T-shaped section;
• the crossing portion bounds a near-wall passage adjacent to said opposite pressure side wall or suction side wall;
• the near-wall passage has a smaller flow aperture area than either of two adjacent ones of the channels directly connected to the near-wall passage;
• wherein the base portion of a first one of the T-shaped partitions extends from the suction side wall of the airfoil, and bounds an aft side of the radial feed channel;
• the crossing portion of the first T-shaped partition is parallel to the pressure side wall of the airfoil, and is not directly attached thereto;
• the base portion of a second one of the T-shaped partitions extends from the pressure side of the airfoil, and bounds an aft side of a second one of the channels;
• and
• the crossing portion of the second T-shaped partition is parallel to the suction side wall of the airfoil, and is not directly attached thereto;
• and
• further comprising a generally J-shaped partition with an end extending forward from the suction side of the airfoil aft of the second T-shaped partition, axially overlapping the crossing portion thereof, and forming an additional near-wall passage adjacent to the pressure side wall of the airfoil.