US 8,984,895 B2 · Metallic ceramic spool for a gas turbine engine

Abstract

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.

Claims22

Dependent claims

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.

3 more elements

A method, comprising:

providing an 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 adjacent to a rotor of the turbine directing an inlet gas towards an inlet of the turbine rotor, and a shroud adjacent to the turbine rotor, the shroud directing an outlet gas towards an outlet of the at least one turbo-compressor spool assembly;
substantially maintaining, 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 engine further 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.

1 more element

Dependencies are inferred from the claim text.

Metallic ceramic spool for a gas turbine engine

Life of this patent

Metallic ceramic spool for a gas turbine engine

Life of this patent

Abstract

Claims22