Turbine inlet nozzle with cooling means

Abstract

A novel turbine inlet nozzle assembly is provided for use with a gas turbine engine and includes unique nozzle cooling means. The turbine inlet nozzle of the present invention comprises an inner annular shroud, an outer annular shroud coaxial with and spaced radially outwardly from the inner shroud and a plurality of circumferentially spaced vanes extending between the shrouds. The shrouds and the vanes, moreover, are of integral construction with each other and, preferably, each vane has a hollow interior. An annular impingement plate is fixedly secured about each axial end to the outer periphery of the outer shroud while, similarly, a second impingement plate is secured at each axial end to the inner periphery of the inner shroud. Moreover, the impingement plates include a plurality of holes formed therethrough and through which a portion of the turbine compressor output is bled to cool the inner and outer shrouds. These holes are arranged both in density and hole size in accordance with the cooling requirements of the shrouds. An impingement liner is also preferably positioned within each of the nozzle vanes. Excessive thermal stress between the outer shroud and its impingement plate is prevented by forming the outer impingement plate in an S shape in cross section adjacent each axial end of the outer impingement plate.