FILM-COOLING HOLE AND METHOD OF PRODUCING IT

摘要

A method of forming a film-cooling hole in a workpiece wall to be coated, the film-cooling hole, in the sequence of flow, having a feed section of constant cross-sectional area and a diffuser section widening toward an outlet at an outer surface of the wall, comprises the following steps: A) selecting the shape and size of the feed section and the diffuser section in order to achieve a desired blow-out rate of cooling air; B) selecting the desired thickness of the coating and the direction from which the coating is effected; and C) producing a film-cooling hole in the wall of the workpiece in such a way that at least portions of the boundary surfaces of the diffuser section are set back in accordance with the desired thickness of the coating, the coating direction and the angle of slope of the boundary surface in the coating direction by such a distance that the original contour selected in step A is essentially obtained after coating with the parameters selected in step B.