TURBINE AIRFOIL WITH LEADING EDGE COOLING PASSAGES COUPLED VIA A PLENUM TO FILM COOLING HOLES

A turbine airfoil (152, 162) includes a body (148, 164) including a wall (150, 166) defining pressure (154, 168) and suction (156, 170) sides, and a leading edge (158, 172) extending between the pressure and suction sides. A cooling circuit (180) inside the wall (150, 166) of the body (148, 164) includes at least one of: a) a suction side to pressure side cooling sub-circuit (182) including a first cooling passage(s) (200) extending from the suction side (156, 170) to the pressure side (154, 168) around the leading edge (158, 172) to a first plenum (186), and a plurality of first film cooling holes (214) communicating with the first plenum (186) and extending through the wall (150, 166) on the pressure side (154, 168); and b) a pressure side to suction side cooling sub-circuit (184) including second cooling passage(s) (202) extending from the pressure side (154, 168) to the suction side (156, 170) around the leading edge (158, 172) to a second plenum (188), and a plurality of second film cooling holes (234) communicating with the second plenum (188) and extending through the wall (150, 166) on the suction side (156, 170).