US5222698A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control of boundary layer flow
Assignee: Rolls Royce PLC
•
Filing: 1992-07-31
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Granted: 1993-06-29
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Expires: 2012-07-31
Abstract
Abstract Turbulence in the boundary layer of a flow of air across a surface is controlled by sucking air from the surface. A plurality of turbulence detectors are located in the surface downstream of apertures provided in the surface. The apertures are connected to a suction pump. Air is sucked through the apertures until the air flow of the most downstream of the detectors is non-turbulent.
Inventors
- 👤 Philip A. Nelson
- 👤 Michael J. Fisher
- 👤 Jean-Luc Rioual
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:57
CPC Classifications
F; F15; F15D; F15D1/00; F15D1/10; F15D1/12; B; B64; B64C; B64C21/00; B64C21/02; B64C21/06; B64C2230/00; B64C2230/04; B64C2230/06; B64D; B64D33/00; B64D33/02; B64D2033/0226; Y; Y02; Y02T; Y02T50/00; Y02T50/10
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
153 words
A structure which defines a surface across which, in operation, there is a fluid flow, said surface having a plurality of apertures therein which are interconnected with suction means wherein a plurality of detectors are provided which are adapted to detect turbulent flow in the boundary layer of said fluid flow adjacent said surface said plurality of detectors being so positioned as to sequentially exposed to said fluid flow downstream of at least some of said plurality of apertures, and control means adapted to control the suction of said suction means in accordance with the outputs of said turbulent flow detectors, said control means being so arranged that said suction means is operated to suck said fluid through said apertures to an extent sufficient to substantially eliminate turbulent flow in said boundary layer of said fluid flow over the most downstream of said detectors but not over the most upstream of said detectors.
Claim 2
Dependent Claim
153 words
A structure which defines a surface across which, in operation, there is a fluid flow, said surface having a plurality of apertures therein which are interconnected with suction means wherein a plurality of detectors are provided which are adapted to detect turbulent flow in the boundary layer of said fluid flow adjacent said surface said plurality of detectors being so positioned as to sequentially exposed to said fluid flow downstream of at least some of said plurality of apertures, and control means adapted to control the suction of said suction means in accordance with the outputs of said turbulent flow detectors, said control means being so arranged that said suction means is operated to suck said fluid through said apertures to an extent sufficient to substantially eliminate turbulent flow in said boundary layer of said fluid flow over the most downstream of said detectors but not over the most upstream of said detectors.
Claim 3
Dependent Claim
23 words
A structure as claimed in claim 1 wherein said apertures are slits generally normal to the direction of flow of said boundary layer.
Claim 4
Dependent Claim
16 words
A structure as claimed in claim 2 wherein said slits are covered by a perforated sheet.
Claim 5
Dependent Claim
20 words
A structure as claimed in claim 3 wherein the perforations in said sheet are each of approximately 0.1 mm diameter.
Claim 6
Dependent Claim
19 words
A structure as claimed in claim 1 wherein each of said turbulent flow detectors (16) is an electret microphone.
Claim 7
Dependent Claim
15 words
A structure as claimed in claim 1 wherein said suction pump is a centrifugal pump.
Claim 8
Dependent Claim
15 words
A structure as claimed in claim 1 wherein said structure is an aircraft engine nacelle.
Claim 9
Dependent Claim
32 words
A structure as claimed in claim 7 wherein said apertures and detectors are located in regions which are between 40 and 70% of the length of said nacelle from its air intake.
References Cited (Backward Citations)
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US4516747A
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US4749150A
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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) | 1996-06-28 | 1996-12-28 | 1997-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-28 | 2000-12-28 | 2001-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-28 | 2004-12-28 | 2005-06-29 | $7700.00 | Window Closed / Lapsed |