Abstract: The film cooling structure includes a wall part extending forward and rearward, and a cooling hole including a tubular inner peripheral surface and inclined such that an outlet is positioned rearward of an inlet. The cooling hole includes a throat having a minimum cross section, and a diffuser part extending from the throat to the outlet. The diffuser part includes a channel cross section expanding rearward and along the wall part as it approaches the outlet. The inner peripheral surface of the cooling hole includes a flat portion extending in a direction perpendicular to the cooling hole and along the wall part at a front part of the inner peripheral surface, and a convex portion projecting from a rear part of the inner peripheral surface toward the flat portion, extending in parallel with the flat portion, and forming the throat between the flat portion and the convex portion.

Abstract: The film cooling structure includes a wall part and a cooling hole inclined such that an outlet is positioned rearward of an inlet. The cooling hole includes a straight-tube part and a diffuser part. The diffuser part includes a flat surface, a curved surface curved rearward and forming, together with the flat surface, a semicircular or semi-elliptical channel cross section larger than that of the straight-tube part, a first section and a second section extending from the first section toward the outlet. In the first section, an area of the channel cross section increases as it approaches the outlet. In the second section, the area of the channel cross section increases as it approaches the outlet at an increase rate smaller than that of the first section or is constant. The diffuser part has a width equal to or twice greater than the depth of the diffuser part.

Abstract: The film cooling structure includes a wall part and a cooling hole inclined such that an outlet is positioned rearward of an inlet. The cooling hole includes a straight-tube part and a diffuser part. The diffuser part includes a flat surface, a curved surface curved rearward and forming, together with the flat surface, a semicircular or semi-elliptical channel cross section larger than that of the straight-tube part, a first section and a second section extending from the first section toward the outlet. In the first section, an area of the channel cross section increases as it approaches the outlet. In the second section, the area of the channel cross section increases as it approaches the outlet at an increase rate smaller than that of the first section or is constant. The diffuser part has a width equal to or twice greater than the depth of the diffuser part.

Abstract: The film cooling structure includes a wall part extending forward and rearward, and a cooling hole including a tubular inner peripheral surface and inclined such that an outlet is positioned rearward of an inlet. The cooling hole includes a throat having a minimum cross section, and a diffuser part extending from the throat to the outlet. The diffuser part includes a channel cross section expanding rearward and along the wall part as it approaches the outlet. The inner peripheral surface of the cooling hole includes a flat portion extending in a direction perpendicular to the cooling hole and along the wall part at a front part of the inner peripheral surface, and a convex portion projecting from a rear part of the inner peripheral surface toward the flat portion, extending in parallel with the flat portion, and forming the throat between the flat portion and the convex portion.