Patent ID: 8166767

Claim:
A method of providing an interface between a combustor and a vane assembly adapted to be mounted to an exit duct of the combustor in a gas turbine engine, the method comprising: providing a vane assembly having a plurality of airfoils radially extending between annular inner and outer platforms, at least the outer platform adapted to cooperate with a flange portion of the combustor exit duct to form an axial sliding joint therebetween; forming a plurality of radial depressions in a portion of the at least the outer platform opposite the flange portion, said radial depressions being disposed solely in local regions of expected higher thermal growth about the circumference of the at least the outer platform such that thermal growth of the entire outer platform is substantially uniform circumferentially therearound, each of said radial depressions providing a reduced thickness of the outer platform over the entirety of the surface of an associated one of the local regions of expected higher thermal growth; determining a maximum amount of thermal growth differential exhibited between the flange portion and the at least the outer platform over an engine operating temperature range; and defining a radial clearance gap between the flange portion and the at least the outer platform at ambient temperature that is slightly greater than the determined maximum amount of thermal growth differential over the engine operating temperature range, such that the radial clearance gap is minimized but maintained during the engine operating temperature range thereby providing substantial radial sealing between the at least the outer platform and the combustor while preventing binding contact therebetween.