Metallic ceramic spool for a gas turbine engine

摘要

A method and apparatus are disclosed for a gas turbine spool design combining metallic and ceramic components in a way that controls clearances between critical components over a range of engine operating temperatures and pressures. In a first embodiment, a ceramic turbine rotor rotates just inside a ceramic shroud and separated by a small clearance gap. The ceramic rotor is connected to a metallic volute. In order to accommodate the differential rates of thermal expansion between the ceramic rotor and metallic volute, an active clearance control system is used to maintain the desired axial clearance between ceramic rotor and the ceramic shroud over the range of engine operating temperatures. In a second embodiment, a ceramic turbine rotor rotates just inside a ceramic shroud which is part of a single piece ceramic volute/shroud assembly. As temperature increases, the ceramic volute expands at approximately the same rate as ceramic shroud and tends to increase the axial clearance gap between the ceramic rotor and ceramic shroud, but only by a small amount compared to a metallic volute attached to the shroud in the same way.

主权项

1. A gas turbine engine, comprising:
at least one turbo-compressor spool assembly, wherein the at least one turbo-compressor spool assembly comprises a compressor in mechanical communication with a turbine, a volute directing an inlet gas towards an inlet of a rotor of the turbine and a shroud adjacent to the rotor of the turbine, the shroud directing an outlet gas towards an outlet of the at least one turbo-compressor spool assembly; and a clearance control device to substantially maintain, during the at least one turbo-compressor spool assembly operation, an operational clearance between the rotor and shroud at a level no greater than about 110% of a non-operational clearance between the rotor and shroud when the at least one turbo-compressor spool assembly is non-operational; and wherein the clearance control device comprises: (a) a metallic shroud carrier connected to an engine housing and case and to the shroud, the shroud being ceramic, (b) a labyrinth metallic seal sleeve, and (c) the volute comprising a labyrinth seal engaging the labyrinth metallic seal sleeve, the labyrinth seal and seal sleeve sealing substantially against gas flow.