APU core compressor providing cooler air supply
AssigneePratt & Whitney Canada Corp.
InventorMario Modafferi
Life of this patent
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Abstract
Air captured from the tips of a compressor of a gas turbine engine is diverted from the engine core and can be collected for auxiliary uses. Gas path separation can be achieved using part-span shrouded compressor blades or using blade tip cut-outs conforming to an airflow dividing annular shroud. In a preferred application for the present invention, the gas turbine engine is the auxiliary power unit of an aircraft. This permits compressed air generation for Auxiliary Power Unit oil cooling and for compartment pressurization without loosing significant mass flow to the engine core, while eliminating the need to provide a separate active cooling system such as an engine driven fan.
Claims20
A gas turbine engine compressor, comprising:
- a rotor adapted to rotate about a central axis, the rotor having a hub and rotor blades extending radially from the hub;
- an annular compressor casing being concentric with said central axis and defining an outer wall;
- said rotor blades having tips wherein at least part of said tips extend to said outer wall, and said blades having end portions near said tips;
- said outer wall extending upstream of said rotor, permitting substantially unobstructed and undivided fluid flow communication between an exterior air source and said rotor;
- a stationary annular shroud within said compressor casing and concentric with said central axis, extending downstream from said rotor, said annular shroud having a leading edge which is substantially parallel to said central axis;
- a first annular duct defined within said annular shroud;
- said annular shroud and said outer wall defining a second annular duct;
- said first duct permitting core fluid flow communication between said rotor and a compressor outlet;
- and
- said second duct adapted to supply air from at least said end portions of said blades for auxiliary use.
A gas turbine engine compressor comprising:
- a rotor adapted to rotate about a central axis, the rotor having a hub and rotor blades extending radially from the hub;
- an annular compressor casing being concentric with said central axis and defining an outer wall;
- said rotor blades having tips wherein at least part of said tips extend to said outer wall, and said blades having end portions near said tips;
- said outer wall extending upstream of said rotor, permitting substantially unobstructed and undivided fluid flow communication between an exterior air source and said rotor;
- a stationary annular shroud within said compressor casing and concentric with said central axis, extending downstream from said rotor;
- a first annular duct defined within said annular shroud, said first duct permitting core fluid flow communication between said rotor and a compressor outlet;
- and
- said annular shroud and said outer wall defining a second annular duct, said second duct adapted to supply air from at least said end portions of said blades for auxiliary use,
- wherein said gas turbine engine is an auxiliary power unit, and wherein an auxiliary use comprises providing cooling air for a passive oil cooling system for said auxiliary power unit.
A gas turbine engine compressor comprising:
- a rotor adapted to rotate about a central axis, the rotor having a hub and rotor blades extending radially from the hub;
- an annular compressor casing being concentric with said central axis and defining an outer wall;
- said rotor blades having tips wherein at least part of said tips are in close proximity with said outer wall, and said blades having end portions near said tips;
- said outer wall extending upstream of said rotor, permitting substantially unobstructed fluid flow communication between an exterior air source and said rotor;
- an annular shroud within said compressor casing and concentric with said central axis, extending downstream from said rotor;
- a first annular duct defined within said annular shroud, said first duct permitting core fluid flow communication between said rotor and a compressor outlet;
- said annular shroud and said outer wall defining a second annular duct, said second duct adapted to supply air from at least said end portions of said blades for auxiliary use;
- a centrifugal impeller downstream of said rotor;
- and
- a stator interposed between said rotor and said centrifugal impeller.
Dependencies are inferred from the claim text.