| 摘要 |
A film cooling passage through the external wall of a hollow airfoil for a gas turbine engine has a metering section in series flow relation with a diffusing section leading to the passage outlet at the external surface of the airfoil over which a hot gas flows during operation. The diffusing section is generally rectangular in cross section perpendicular to the axis of the passage. Upstream and downstream longitudinally extending, spaced apart, facing surfaces of the diffusing section are joined together by a pair of spaced apart side walls which face each other and diverge from each other in the longitudinal direction toward the outlet of the passage. These side walls blend, along their length, with the downstream surface as a smooth curve of large radius. The diameter of the corner curvature of the passage is on the same order of magnitude as the distance between the upstream and downstream surfaces of the diffusing section at the location in question. The large corner curvatures, as opposed to filet radii, allow the side walls to diverge from each other at a greater angle without separation of the coolant fluid therefrom, permitting the spreading of smaller amounts of coolant air over a larger area of the airfoil external surface. |
