High coverage shaped diffuser film hole for thin walls

A cooled wall comprising

• an outer surface exposed to a hot gas stream flowing in a first direction over said outer surface:
• an inner surface defining an internal cavity containing a coolant fluid;
• and
• a plurality of coolant passages extending between said inner surface and said outer surface through which said coolant fluid flows from said inner surface to said outer surface, each passage having a passage outlet connected to said outer surface and over which the hot gas stream flows in said downstream direction, each passage including
• a metering section connected to said inner surface, said metering section adapted to receive a flow of coolant from the coolant compartment and to control the rate of flow of coolant fluid through said passage, and
• a diffusing section connected to said passage outlet and having a longitudinal axis extending therethrough, a diffusing section inlet opposite said passage outlet and connected to the metering section, a first side surface spaced apart from and facing a second side surface, a third surface spaced apart from and facing a fourth surface, each of said side surfaces connected to and extending between said third and fourth surfaces, said fourth surface is downstream of said first, second, and third surfaces and said fourth surface is curved and curls away from said axis in the direction of said passage outlet, and said first, second, third and fourth surfaces are connected to, and extend between, said diffusing section inlet and said passage outlet;
• wherein immediately adjacent the metering section the fourth surface diverges from the axis at an angle .delta..sub.1 of at least five degrees.