APPARATUS AND METHOD FOR MINIMIZING DIFFERENTIAL THERMAL EXPANSION OF GAS TURBINE VANE STRUCTURES

摘要

18 56,075 An apparatus and method are provided for minimizing differential thermal expansion in external cooling air structures formed on the shrouds of the vane segments Or a gas turbine. The external cooling air structure is formed from a laminate comprised of two layers joined in sandwich-like fashion. A passageway, which may be of a serpentine arrangement, is formed between the two layers of the laminate. Hot gas flowing over the shroud is directed through the passageway, thereby heating the structure 50 that its temperature is close to that of the shroud. Cooling air is bled into the hot gas directed to the passageway so as to reduce the temperature of the hot gas flowing through the passageway and prevent overheating of the external cooling air structure.