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US3730639A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fan or compressor for a gas turbine engine
Assignee: UK Secretary of State for Defence
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Filing: 1971-07-16
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Granted: 1973-05-01
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Expires: 1991-07-16
Abstract
Abstract The noise generated by a fan is to be largely due to the blade tips passing the turbulent boundary layer which is attached to the duct wall. The present invention provides a slot positioned immediately upstream of the fan, the slot being connected to a duct and means for providing suction in the duct so that the boundary layer is removed and the blade tips pass substantially laminar flow.
Inventors
- 👤 C Moore
- 👤 B Barry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:20
CPC Classifications
F; F02; F02C; F02C7/00; F02C7/04; F02C7/045; F04; F04D; F04D27/00; F04D27/02; F04D27/0207; F04D27/0215; Y; Y10; Y10S; Y10S415/00; Y10S415/914
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
174 words
A fan or compressor for a gas turbine engine comprising: an annular duct having an outer wall; a rotor adapted to rotate on the axis of said duct; at least one row of blades mounted on said rotor for rotation within said duct, Said row of blades having blade tips which pass in close proximity to said duct outer wall, said outer wall of said duct extending upstream of said at least one row of blades and said duct being completely unobstructed upstream of said at least one row of blades; means for reducing noise caused by the turbulent boundary layer and blade interaction therewith, said means comprising: an annular slot located in said outer wall of said duct immediately upstream of said at least one row of blades, said annular slot being arranged to remove a sufficient amount of turbulent boundary layer from the surface of said duct outer wall upstream of said blades so there is no boundary layer turbulence in the proximity of the blade tips when said rotor is rotating.
Claim 2
Dependent Claim
174 words
A fan or compressor for a gas turbine engine comprising: an annular duct having an outer wall; a rotor adapted to rotate on the axis of said duct; at least one row of blades mounted on said rotor for rotation within said duct, Said row of blades having blade tips which pass in close proximity to said duct outer wall, said outer wall of said duct extending upstream of said at least one row of blades and said duct being completely unobstructed upstream of said at least one row of blades; means for reducing noise caused by the turbulent boundary layer and blade interaction therewith, said means comprising: an annular slot located in said outer wall of said duct immediately upstream of said at least one row of blades, said annular slot being arranged to remove a sufficient amount of turbulent boundary layer from the surface of said duct outer wall upstream of said blades so there is no boundary layer turbulence in the proximity of the blade tips when said rotor is rotating.
Claim 3
Dependent Claim
37 words
A fan or compressor as claimed in claim 1 including suction means operatively connected to said annular slot for assisting in removal of turbulent boundary layer from the surface to said outer wall upstream of the blades.
Claim 4
Dependent Claim
19 words
A fan or compressor as claimed in claim 1 which is a single stage fan without inlet guide vanes.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-30 | 1976-10-30 | 1977-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-30 | 1980-10-30 | 1981-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-30 | 1984-10-30 | 1985-05-01 | $7700.00 | Window Closed / Lapsed |