Airfoil for an engine turbine

An airfoil (10) comprising:

• a leading edge (11) and a trailing edge (1), the trailing edge (1) being located axially downstream from the leading edge (11) according to a flow direction that corresponds to the direction of an air flow;
• a suction side wall (2) and a pressure side wall (3), both walls (2, 3) extending axially between the leading edge (11) and the trailing edge (1), the suction side wall (2) being spaced from the pressure side wall (3) and defining between them a central cavity of the airfoil (10), the central cavity being configured to allow the passage of a cooling flow inside the airfoil (10);
• two side walls (13) extending perpendicular to the flow direction and located between the suction side wall (2) and the pressure side wall (3);
• a cavity region (8) formed in the central cavity between the suction side wall (2) and the pressure side wall (3), said cavity region (8) extending axially between the leading edge (11) and the trailing edge (1), being the cavity region (8) proximal to the trailing edge (1);
• wherein the cavity region (8) comprises:
• at least a pair of a V-shaped straight ribs (4, 5) extending axially towards the trailing edge (1),
• at least one narrow hole (6) proximal to the trailing edge (1) and bounded by proximal ends (4a, 5a) of the pair of straight ribs (4, 5),
• at least one wide hole (7) distal to the trailing edge (1) and bounded by the distal ends (4b, 5b) of the pair of straight ribs (4, 5), and
• wherein:
• the surface of the at least one narrow hole (6) is smaller than the surface of the at least one wide hole (7), and
• at least one nozzle duct (9a) and at least one diffusing duct (9b) formed between each of the at least one pair of V-shaped straight ribs (4, 5), or between one V-shaped straight rib (4, 5) and one of the side walls (13);
• wherein the at least one nozzle duct (9a) and the at least one diffusing duct (9b) are bounded by the at least one narrow hole (6) and by the at least one wide hole (7).