WO2010115656A1 - Dispositif de commande d'écoulement destiné à commander un écoulement de fluide sur une surface - Google Patents

Dispositif de commande d'écoulement destiné à commander un écoulement de fluide sur une surface Download PDF

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Publication number
WO2010115656A1
WO2010115656A1 PCT/EP2010/052265 EP2010052265W WO2010115656A1 WO 2010115656 A1 WO2010115656 A1 WO 2010115656A1 EP 2010052265 W EP2010052265 W EP 2010052265W WO 2010115656 A1 WO2010115656 A1 WO 2010115656A1
Authority
WO
WIPO (PCT)
Prior art keywords
passage
control device
flow
inlet
flow control
Prior art date
Application number
PCT/EP2010/052265
Other languages
English (en)
Inventor
Samuel Alexander Mason
Original Assignee
Rolls-Royce Plc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rolls-Royce Plc filed Critical Rolls-Royce Plc
Publication of WO2010115656A1 publication Critical patent/WO2010115656A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C21/00—Influencing air flow over aircraft surfaces by affecting boundary layer flow
    • B64C21/02—Influencing air flow over aircraft surfaces by affecting boundary layer flow by use of slot, ducts, porous areas or the like
    • B64C21/025—Influencing air flow over aircraft surfaces by affecting boundary layer flow by use of slot, ducts, porous areas or the like for simultaneous blowing and sucking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C21/00—Influencing air flow over aircraft surfaces by affecting boundary layer flow
    • B64C21/02—Influencing air flow over aircraft surfaces by affecting boundary layer flow by use of slot, ducts, porous areas or the like
    • B64C21/08—Influencing air flow over aircraft surfaces by affecting boundary layer flow by use of slot, ducts, porous areas or the like adjustable
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/12—Blades
    • F01D5/14—Form or construction
    • F01D5/141—Shape, i.e. outer, aerodynamic form
    • F01D5/145—Means for influencing boundary layers or secondary circulations
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15D—FLUID DYNAMICS, i.e. METHODS OR MEANS FOR INFLUENCING THE FLOW OF GASES OR LIQUIDS
    • F15D1/00—Influencing flow of fluids
    • F15D1/10—Influencing flow of fluids around bodies of solid material
    • F15D1/12—Influencing flow of fluids around bodies of solid material by influencing the boundary layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C2230/00—Boundary layer controls
    • B64C2230/04—Boundary layer controls by actively generating fluid flow
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C2230/00—Boundary layer controls
    • B64C2230/06—Boundary layer controls by explicitly adjusting fluid flow, e.g. by using valves, variable aperture or slot areas, variable pump action or variable fluid pressure
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00—Aeronautics or air transport
    • Y02T50/10—Drag reduction
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00—Aeronautics or air transport
    • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Definitions

  • This invention relates to a flow control device for controlling a fluid flow over a surface and particularly but not exclusively relates to a flow control device comprising an ejector.
  • flow control devices may be used to control and manipulate boundary layer flows over surfaces. This is usually done with the intention of increasing the aerodynamic efficiency of the surface, which may for example, be part of a duct, aerofoil, or wing. Typically a very small flow rate of control fluid is used to 'control' the mainstream flow.
  • FIG. 1a there are essentially two different classes of flow control device. Firstly, as shown in Figure 1a, there are flow control devices which use blowing by virtue of a high pressure air source 2. With such a device, momentum is effectively injected locally into the adjacent boundary layer. This process allows the boundary layer to overcome larger adverse pressure gradients than would otherwise have been possible, thereby preventing or delaying flow separation and reducing drag.
  • the flow control device With the first class of flow control device it is necessary to increase the amount of momentum that the flow control device delivers to the adjacent boundary layer to increase its effectiveness. This may be achieved by increasing the pressure of the control fluid. However, this requires additional energy input, which is undesirable. Furthermore, in engineering applications a higher pressure reservoir may not be available. Similarly, the effectiveness of the second class of flow control device may be increased by increasing the suction rate. This is also undesirable since the control fluid is degraded by this process, and becomes less useful for doing mechanical work. This requires an additional energy input and so is also undesirable.
  • the present invention therefore seeks to address these issues.
  • a flow control device for controlling a fluid flow over a surface
  • the flow control device comprises: a first passage comprising a first inlet and an outlet, the outlet being disposed on the surface; the first passage comprises a Venturi; a second passage comprising a second inlet, the second inlet being disposed on the surface; and a third passage for receiving a fluid flow from a flow source; wherein the first, second and third passages are arranged such that the second and third passages feed into the first inlet of the first passage and that, in use, a portion of the fluid flow over the surface is drawn into the second passage, mixes with the fluid flow from the flow source received via the third passage, and exits the outlet disposed on the surface via the first passage.
  • the second inlet disposed on the surface may be immediately adjacent to the outlet disposed on the surface. At least a portion of the second inlet may be arranged on the surface so as to be downstream of the outlet with respect to the fluid flow over the surface. Alternatively, the second inlet may be arranged on the surface so as to be upstream of the outlet with respect to the fluid flow over the surface.
  • the first passage and/or outlet may be formed by a first slot in the surface.
  • the second passage and/or second inlet may be formed by a second slot in the surface.
  • the third passage may be formed by a third slot.
  • One ore more of the first, second and third slots may be substantially longitudinal.
  • the flow control device may further comprise a fourth passage comprising a fourth inlet disposed on the surface.
  • the fourth passage may be arranged such that the fourth passage feeds into the first inlet of the first passage.
  • the fourth passage and/or fourth inlet may be formed by a fourth slot in the surface.
  • the fourth slot may be substantially longitudinal.
  • the fourth inlet may be arranged on the surface so as to be downstream of the outlet with respect to the fluid flow over the surface.
  • the fourth inlet disposed on the surface may be immediately adjacent to the outlet disposed on the surface.
  • the second inlet may be arranged such that the second inlet substantially surrounds the outlet on the surface.
  • the second inlet may encircle the outlet on the surface.
  • the second inlet and/or second passage on the surface may be formed by a substantially continuous slot surrounding the outlet on the surface.
  • the flow control device may comprise an ejector or injector.
  • a gas turbine engine may comprise the flow control device as described above.
  • a method of controlling a flow over a surface using a flow control device comprising: providing a second fluid flow into the flow control device from a second inlet disposed on the surface; providing a third fluid flow into the flow control device from a flow source; mixing the second fluid flow with the third fluid flow to form a first fluid flow; directing the first fluid flow through a first passage of the flow control device; drawing the second fluid flow into the flow control device by virtue of a Venturi in the first passage; and expelling the first fluid flow from the flow control device through and outlet of the first passage disposed on the surface.
  • the method may further comprise providing an oscillatory flow from the flow source into the flow control device.
  • the method may further comprise arranging at least a portion of the second inlet on the surface so as to be downstream of the outlet with respect to the fluid flow over the surface.
  • the method may further comprise arranging the second inlet disposed on the surface so as to be immediately adjacent to the outlet disposed on the surface.
  • Figure 1 a shows a side view of a first class of flow control device and Figure 1 b show a side view of a second class of flow control device;
  • Figure 2 is a side view of a flow control device according to a first embodiment of the invention.
  • Figure 3 is a perspective view of a flow control device according to the first embodiment of the invention.
  • Figure 4 is a perspective view of a flow control device according to a second embodiment of the invention.
  • a flow control device 6 is suitable for controlling a freestream flow 8 over a surface 7 of a body.
  • the flow control device 6 comprises a first passage 10, a second passage 20, a third passage 30 and a fourth passage 40.
  • the first passage 10 comprises a first inlet 12 within the body and an outlet 14 disposed on the surface 7.
  • the second passage 20 comprises a second inlet 22 disposed on the surface 7 and the fourth passage 40 comprises a fourth inlet 42 also disposed on the surface 7.
  • the third passage 30 is arranged to receive a fluid flow from a flow source (not shown).
  • the flow source is separate from the flow control device 6 and the flow source connects to the flow control device 6 via the third passage 30.
  • the flow source may be any known source of flow, for example a pump or an electrically actuated jet, providing a control jet which may be a high speed fluid flow.
  • the flow source may be provided within the body or outside the body.
  • the first passage 10 is provided by first and second internal partitions 16, 18, which are disposed within the flow control device 6.
  • the second passage 20 is provided between a first wall 26 and the first internal partition 16.
  • the first wall 26 is a continuation of the surface 7 of the body and the first wall 26 is angled with respect to the surface 7 with a smooth corner between the first wall 26 and surface 7.
  • the fourth passage 40 is provided between a second wall 46 and the second internal partition 18.
  • the second wall 46 is a continuation of the surface 7 on a side of the body opposite to the first wall 26 and the second wall 46 is angled with respect to the surface 7 with a smooth corner between the second wall 46 and surface 7.
  • a structure (not shown), for example a series of webs or ribs, is included to support the first and second internal partition walls 16, 18 with respect to the first and second walls 26, 46.
  • the second and fourth passages 20, 40 are disposed either side of the first passage 10 and the flow control device is substantially symmetrical about the first passage 10.
  • the second inlet 22 is arranged on the surface 7 so as to be upstream of the outlet 14 with respect to the fluid flow 8.
  • the fourth inlet 40 is arranged on the surface 7 so as to be downstream of the outlet 14 with respect to the fluid flow 8.
  • the second inlet 22 is immediately adjacent to the outlet 14, because the second inlet 22 and outlet 14 are separated by the first internal partition 16, which is narrow with respect to the overall length of the surface.
  • the fourth inlet 42 is immediately adjacent to the outlet disposed on the surface, because the fourth inlet 42 and outlet 14 are separated by the second internal partition 18, which is narrow with respect to the overall length of the surface.
  • the first, second and third passages 10, 20, 30 are arranged such that the second, third and fourth passages 20, 30 feed into the first inlet 12 of the first passage 10. With this arrangement a portion 9 of the fluid flow 8 over the surface 7 is drawn into the second and fourth passage 20, mixes with the fluid flow from the flow source received via the third passage 30, and exits the outlet 14 via the first passage 10.
  • the first passage 10 comprises a narrowing (or nose) 17 so as to form a Venturi in the first passage. Owing to the Bernoulli effect, a low pressure exists at the narrowing 17. This low pressure assists in drawing fluid in from the second and fourth inlets 22, 42 and through the second and fourth passages 20, 40.
  • the second internal partition 18 and hence the fourth passage 40 may be omitted.
  • the first internal partition 16 and hence the second passage 20 may be omitted.
  • the flow control device 6 comprises first, second, third and fourth slots 19, 29, 39, 49.
  • the first passage 10 and outlet 14 are formed by the first slot 19.
  • the second passage 20 and second inlet 22 are formed by the second slot 29.
  • the third passage 30 is formed by a third slot 39.
  • the fourth passage 40 and fourth inlet 42 are formed by the fourth slot 49.
  • the first, second, third and fourth slots 19, 29, 39, 49 are substantially longitudinal and are substantially parallel.
  • a flow control device 106 comprises an axisymmetric arrangement, which is in contrast to the substantially two-dimensional slots of the first embodiment shown in Figure 3.
  • the second embodiment is otherwise identical to the first embodiment and Figure 2 could also represent a section of the second embodiment, except that the second and fourth passages shown in Figure 2 are part of the same second passage of the second embodiment.
  • a second inlet 122 and second passage 120 arranged with the second inlet 122 substantially surrounding an outlet 114 on the surface 107 and a first passage 110.
  • the second inlet 122 therefore encircles the outlet 114 such that at least a portion of the second inlet 122 is arranged on the surface 107 so as to be downstream of the outlet 114 with respect to the fluid flow over the surface. A further portion of the second inlet 122 is arranged upstream of the outlet 114.
  • the second inlet 122 and second passage 120 are formed by a substantially continuous slot 129 surrounding the outlet 114 and the first passage 110.
  • the first and second passages 110, 120 are divided by an internal partition wall 116.
  • the second passage 120 is provided between the internal partition wall 116 and a wall 126.
  • the wall 126 is a continuation of the surface 107 and the wall 126 is angled with respect to the surface 107 with a smooth corner between the wall 126 and surface 107.
  • a structure (not shown), for example a series of webs or ribs, is included in the second embodiment to support the internal partition wall 116 with respect to the wall 126.
  • the flow area through the first passage 10, 110 of the flow control device will typically be approximately five times the area of the third passage 30, 130 fed by the flow source.
  • the overall width of the flow control device depends on the particular application, but may typically be several millimetres.
  • the flow control device supplements the performance of blowing flow control devices.
  • the flow control device increases the momentum of the flow from the flow source by mixing in flow from the freestream flow 8 sucked in through the second and/or fourth passages 20, 40.
  • This suction may be achieved in part by the Bernoulli effect caused the narrowing 17 (the reduced cross- sectional area at narrowing 17 increases the flow velocity, which in turn reduces the pressure).
  • the suction may also be achieved in part by the rapid viscous mixing of the entrained portion with the flow from the flow source within the first passage 10 (the mixing process may increase local flow velocities, which in turn reduces the pressure).
  • the reduced cross-sectional area of narrowing 17 and the mixing process in the first passage 10 may combine to further increase the suction effect and may combine in a synergistic manner.
  • the increase in suction further increases the quantity of flow entrained through the second and/or fourth passages 20, 40, thereby further increasing the momentum imparted to the freestream flow 8 on exit from the outlet 14.
  • the divergent portion of the first passage 10 causes diffusion of the mixed flow, giving enhanced entrainment.
  • the present invention also offers the additional benefit of providing suction to the target boundary layer, thus further enhancing its flow control effectiveness.
  • the fluid entrained by the second and/or fourth inlets 22, 42 is sucked from the adjacent boundary layer, and does not come from an independent source.
  • the entrained portion of the freestream flow 8 may include at least a part or all of the boundary layer on the surface 7. In this way, additional control of the adjacent boundary layer is possible through localised boundary layer sucking.
  • a boundary layer is unable to grow between the second and/or fourth inlets and the outlet and this further serves to reduce the drag on the surface.
  • the flow control device may be driven by an unsteady flow from the flow source, for example an oscillating flow.
  • An electrically actuated eg a synthetic jet actuator
  • a pressurised fluid source may not necessarily be required.
  • the flow direction in the third passage 30 may oscillate.
  • the direction of the flow in the first passage 10 may not oscillate due to the net positive flow from the second and/or fourth passages 20, 40 mixing with the flow from third passage 30.
  • a flow control device with an oscillating flow source may be more compact than those driven by steady jets.
  • the 'cost' of employing flow control increases with the pressure and flow rate of the flow from the flow source.
  • the present invention provides a greater flux of momentum (i.e. a greater ability to control the freestream) than is currently possible, without requiring any increase in pressure, flow or additional mechanical power input. In this respect, the present invention increases the 'efficiency' of the flow control system.
  • the flow control device may comprise an ejector or injector, such that the above-mentioned flow passages provide an ejector or injector.
  • the flow control device according to the present invention may form part of a gas turbine, for example a jet engine or a stationary gas turbine for power generation.
  • the flow control device may be used on ducting within a gas turbine, for example on the hub and/or casing walls, or may even be used on aerofoil surfaces within a gas turbine, for example blade surfaces.
  • the flow control device may also be used in heat exchangers. More generally, the flow control device according to the present invention may be used for drag reduction eg on aerofoils or wings, mixing enhancement, heat transfer enhancement, and jet vectoring.

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  • Engineering & Computer Science (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Nozzles (AREA)
  • Jet Pumps And Other Pumps (AREA)

Abstract

L'invention porte sur un dispositif de commande d'écoulement (6) destiné à commander un écoulement de fluide sur une surface (7), le dispositif de commande d'écoulement comprenant : un premier passage (10) comprenant un premier orifice d'entrée (12) et un orifice de sortie (14), l'orifice de sortie (14) étant disposé sur la surface (7), et le premier passage (10) comprenant un venturi; un deuxième passage (20) comprenant un deuxième orifice d'entrée (22), le deuxième orifice d'entrée (22) étant disposé sur la surface (7); et un troisième passage (30) destiné à recevoir un écoulement de fluide à partir d'une source d'écoulement; les premier, deuxième, troisième passages sont disposés de telle sorte que les deuxième et troisième passages alimentent le premier orifice d'entrée du premier passage et que, lors de l'utilisation, une partie de l'écoulement de fluide sur la surface est aspirée dans le deuxième passage, se mélange avec l'écoulement de fluide à partir de la source d'écoulement reçue par l'intermédiaire du troisième passage, et quitte l'orifice de sortie disposé sur la surface par l'intermédiaire du premier passage.
PCT/EP2010/052265 2009-04-06 2010-02-23 Dispositif de commande d'écoulement destiné à commander un écoulement de fluide sur une surface WO2010115656A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB0905941.1A GB0905941D0 (en) 2009-04-06 2009-04-06 A flow control device
GB0905941.1 2009-04-06

Publications (1)

Publication Number Publication Date
WO2010115656A1 true WO2010115656A1 (fr) 2010-10-14

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GB (1) GB0905941D0 (fr)
WO (1) WO2010115656A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3363733A1 (fr) 2017-02-18 2018-08-22 Jean-Eloi William Lombard Mécanisme de commande d'écoulement passif destiné à supprimer les ondes de tollmien-schlichting, retarder une transition à turbulence et réduire la traînée

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2841344A (en) * 1955-11-28 1958-07-01 Stroukoff Michael Boundary layer control
WO1991009776A1 (fr) * 1989-12-29 1991-07-11 Venturi Applications, Inc. Profil d'aile ameliore par un venturi
US20060273197A1 (en) * 2005-05-23 2006-12-07 Seyed Saddoughi Dual bimorph synthetic pulsator

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2841344A (en) * 1955-11-28 1958-07-01 Stroukoff Michael Boundary layer control
WO1991009776A1 (fr) * 1989-12-29 1991-07-11 Venturi Applications, Inc. Profil d'aile ameliore par un venturi
US20060273197A1 (en) * 2005-05-23 2006-12-07 Seyed Saddoughi Dual bimorph synthetic pulsator

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3363733A1 (fr) 2017-02-18 2018-08-22 Jean-Eloi William Lombard Mécanisme de commande d'écoulement passif destiné à supprimer les ondes de tollmien-schlichting, retarder une transition à turbulence et réduire la traînée

Also Published As

Publication number Publication date
GB0905941D0 (en) 2009-05-20

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