Abradable coating in a gas turbine engine
AssigneeSundstrand Corporation
InventorsEric J. Alexander, Robert W. Fawley, James C. Napier
Life of this patent
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Abstract
An abradable coating is provided for use on a composite substrate which has a coefficient of thermal expansion substantially similar to that of the substrate and which is formed with a matrix resin of the same type of resin used to form the substrate. In particular, with a composite substrate formed from carbon or graphite fibers impregnated with a polyimide resin, an abradable coating formed from carbon or glass microballoons in a polyimide resin matrix has been found to avoid delamination as a result of thermal cycling between -65.degree. F. and 500.degree. F. Accordingly, that abradable coating is particularly suitable for use with composite compressor shrouds in gas turbine engines and aircraft auxiliary power units.
Claims25
In an apparatus having a substrate formed from composite material, that material including a fibrous mass impregnated with a resin, an abradable coating applied to said composite material, comprising:
- a matrix formed from said resin and particulate material suspended in said resin,
- said particulate material being formed as microballoons having a coefficient of thermal expansion and included in a ratio as compared to said resin such that said abradable coating exhibits a coefficient of thermal expansion substantially similar to the coefficient of thermal expansion of said substrate, thereby allowing said abradable coating to be retained on said substrate over a wide range of temperatures.
A compressor comprising:
- a compressor wheel and a shroud disposed over at least part of said compressor wheel;
- said compressor wheel being rotatable and having a hub with a plurality of compressor blades on said hub;
- said shroud being formed from a composite material having a fibrous mass impregnated with a resin;
- and
- said shroud having an abradable coating thereon, that coating being formed from a mixture of particulate matter and the same type of resin as the resin that is formed in said shroud.
A gas turbine engine comprising:
- a rotor movable about a rotational axis and including a compressor wheel and a turbine wheel,
- said compressor wheel having a hub with a plurality of blades on that hub,
- said turbine wheel being formed so as to receive gases of combustion and be driven thereby to in turn drive said compressor wheel,
- a compressor shroud surrounding said blades in close proximity thereto and being formed from a composite material, that composite material including a fibrous mass impregnated with a resin,
- a source of fuel,
- a combustor means, in fluid communication with said compressor wheel, for receiving compressed air therefrom and fuel from said source and combusting said air and fuel to provide said gases of combustion,
- a turbine nozzle means, connected to said combustor means and adjacent said turbine wheel, for directing said gases of combustion at said turbine wheel, and
- an abradable coating on said shroud adjacent to said blades, said coating being formed from particulate matter suspended in a matrix including said resin.
An aircraft having a gas turbine engine therein for use as an auxiliary power unit, said engine including a compressor and a shroud disposed about said compressor, said compressor including a hub and a plurality of blades extending outwardly from said hub toward said shroud, said hub having a central axis and being rotatable about said axis, said compressor and said shroud being subject to thermal cycling between operational temperatures and at rest temperatures, said shroud being formed from composite materials including a fibrous mass suspended in a matrix including a resin, and said shroud also including an abradable coating thereon, said abradable coating being formed from materials having a coefficient of thermal expansion sufficiently similar to the coefficient of thermal expansion of said shroud and applied to said shroud such that it does not separate from said shroud as a result of said thermal cycling.
An article of manufacture comprising:
- a substrate formed from composite material including a fibrous mass impregnated with a resin;
- and
- an abradable coating applied to a surface of said substrate,
- said abradable coating including particulate matter suspended in said resin.
Dependencies are inferred from the claim text.