• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Turbomachine propeller (20), comprising a hub (22) and an annular row of blades (24) extending substantially radially around said hub, characterized in that it comprises means (26) for sampling ambient gas in operation , and in that at least some of the blades comprise internal cavities (30) for circulating said sampled gas as well as means (36) for ejecting said gas sampled from Coanda surfaces of the blades.
    公开号:FR3036144A1
    申请号:FR1554169
    申请日:2015-05-11
    公开日:2016-11-18
    发明作者:Josselin Coupard；Benjamin James William Godard
    申请人:SNECMA SAS；
    IPC主号:
    专利说明:

    [0001] TECHNICAL FIELD The present invention relates to a turbomachine propeller, in particular for an aircraft. This propeller may for example be an unsheathed propeller of a turboprop or a fan propeller of the blower type of a turbojet engine. STATE OF THE ART Conventionally, a turbomachine propeller comprises a hub and an annular row of blades which extend substantially radially around said hub. This type of propeller is equipped for example with a turboprop, the propeller being mounted upstream of the turboprop (with reference to the direction of flow of the gas around the turboprop in operation). The propeller is traversed by this operating gas, which is compressed and accelerated by the propeller to provide a propulsion force to the turboprop. The delamination of the boundary layer on a propeller (especially at the level of the blade roots) represents a significant problem for a turboprop engine, notably causing loss of efficiency or even instability in terms of operability, that is to say in the field engine operating conditions (eg floating margins of air around the blades, which result in Von Karman vortices, etc.). This boundary layer is subjected to a suction phenomenon. The boundary layer of a helix is centrifuged by the rotation of the helix. The part of the blade closest to the axis of rotation of the helix sees its maximum incidence (and therefore its lift) very greatly increased compared to a profile whose boundary layer would not be so sucked. It is this phenomenon which explains the strong thrust of a propeller when the aircraft is at the stopping point (stopped before take-off).
    [0002] The setting of the propeller as a function of the relative wind makes it possible to generate an aerodynamic result allowing the traction of the aircraft. It is therefore possible to model a helix by a wing and thus study the phenomenon of stalling of the helix or delamination of the boundary layers, which reduces the pulling power of the helix. The diagrams of FIG. 1 show, for example, the influence of the angle of incidence of the relative wind 10 on the phenomenon of separation on a blade 12 of the helix. In the diagram above, the angle of incidence is relatively low and the lift is represented by the arrow 14. In the middle diagram, a stall limit is reached, the point 16 representing a point of separation. The lift 14 'is here maximum. In the bottom diagram, a stall takes place, the reference 18 representing the airflow taken off. The lift 14 "drops The problem of the separation leads to a loss of traction by the propeller due to a change in the relative wind and results in overconsumption of the engine and additional heating.
    [0003] SUMMARY OF THE INVENTION The present invention aims to limit the separation on the blades of a turbomachine propeller, preferably over their entire radial dimension. The Coanda effect is the result of the attraction of a gas flow by a surface of Coanda. The flow of gas follows the surface of Coandà and undergoes a deviation before detaching it with a trajectory different from that which it had upstream. The present invention proposes to use this effect to achieve the aforementioned objective. The invention proposes for this purpose a turbomachine propeller, comprising a hub and an annular row of blades extending substantially radially around said hub, characterized in that it comprises means for taking ambient gas in operation, and at least some of the blades comprise internal cavities for circulating said sampled gas, as well as means for ejecting said gas sampled from said surfaces of Coandà blades.
    [0004] The invention consists in particular in using the technique of ingestion of ambient gas in a turbomachine propeller to energize the boundary layer of the propeller by blowing gas on the blades. This produces an acceleration of the gas flowing around the blades Coandà effect and allows the formation of a boundary layer on the blades more resistant to detachment, especially at high incidences of the aircraft. The propeller according to the invention may comprise one or more of the following characteristics, taken in isolation from one another or in combination with each other: the hub comprises said sampling means, said sampling means comprise at least one sampling orifice, located for example on an axis of rotation of the helix or in the extension of this axis, said hub comprises an internal fluidic connection chamber of the sampling means to said internal cavities of the blades, an organ such as that a centrifugal turbine or a convergent is mounted in said chamber to drive the gas drawn radially to the internal cavities of the blades, said ejection means are configured to eject gas on Coand surfaces of the extrados of the blades; in operation and in a known manner, a depression takes place on the upper surface of a blade; the gas acceleration on the extrados of a blade results in a better stability of the boundary layer, which thus does not tend to detach itself from the blade, the said ejection means comprise ejection slots in fluid communication with said inner cavities of the blades, each of said cavities has in section an elongate shape substantially along a rope connecting a leading edge to a trailing edge of the corresponding blade, the sectional shape of each cavity is comparable to the sectional profile of a blade and comprises a first peripheral portion comparable to a lower surface of said profile and located on the extrados side of the corresponding blade, and a second peripheral portion comparable to an extrados of said profile; and located on the side of the underside of said corresponding blade; the pipe thus has in section an "inverted" profile with respect to that of the blade, which makes it possible to improve the performance of the Coand® effect, - said first and second peripheral portions are connected together by a third peripheral portion curved which is located on the leading edge side of said corresponding blade, and which is configured for the rotation of the sample gas before its ejection by said ejection means, and - the sampling means and / or said means ejection comprises at least one gas flow control valve taken / ejected; the valve can be configured to enable or stop engine sampling according to flight requirements. The present invention also relates to a turbomachine, such as a turboprop, comprising at least one helix as described above, which is preferably unsheathed. DESCRIPTION OF THE FIGURES The invention will be better understood and other details, characteristics and advantages of the invention will emerge more clearly on reading the following description given by way of nonlimiting example and with reference to the appended drawings in which: FIG. 1 comprises diagrams showing the flow of an air flow around a propeller blade, as a function of the incidence of the air flow with respect to the blade; FIG. 2 is a very schematic view in axial section of a turbomachine propeller of the turboprop type; and FIG. 3 is a diagrammatic sectional and perspective view of a blade of the helix of FIG. 2. DETAILED DESCRIPTION FIG. 1 has been described in the foregoing. FIG. 2 shows a propeller 20 of a turbomachine, and in particular a turboprop, according to the invention, this propeller 20 comprising a central hub 22 aligned on an axis A of rotation of the propeller, and carrying an annular row of blades. 24, which extend substantially radially with respect to the axis A at the periphery of the hub. The blades 24 and the hub 22 form a unitary assembly movable in rotation about the axis A. As shown in the figure, this propeller is generally mounted at the upstream end of a shaft of the turbomachine. Conventionally, a turbomachine comprises, from upstream to downstream, in the direction of flow of gases, at least one compressor, an annular combustion chamber, and at least one turbine which comprises a shaft 39 for driving the propeller. Part of the airflow 24 passing through the propeller feeds the compressor to be compressed, mixed with fuel and burned in the combustion chamber, and then expanded in the turbine. The other part of the air flow which is compressed and accelerated by the propeller and which flows around the nacelle of the turbomachine here provides most of the thrust of the turbomachine.
    [0005] Figure 2 very schematically shows the general principle of the invention that the propeller 20 includes operating gas sampling means 26, and at least some of the propeller blades 24 comprise internal cavities 30 circulating said sampled gas as well as means for ejecting said gas sampled from coand surfaces of the blades. In the example shown, the hub 22 comprises a central orifice 26, centered on the axis A, of gas sampling, this orifice 26 opening into an internal chamber 28 of the hub which is in fluid communication with the internal cavities 30 of the blades .
    [0006] As can be seen in the figures, the withdrawn gas, such as air, enters the orifice 26 and is conveyed from the radially outward chamber (relative to the axis A) in the cavities 30 of the blades. For this, a centrifugal turbine 32 centered on the axis A is mounted in the chamber 28 and is integral in rotation with the propeller. The centrifugal turbine 32 may be attached, with the propeller 20, to the upstream end of the propeller shaft 39. Alternatively, this turbine 32 could be replaced by a simple convergent comprising for example a conical surface centered on the axis A and whose tip would be directed upstream, and thus forcing the gas taken upstream to flow radially towards the outside of the convergent, towards the internal cavities 30 of the blades. The turbine 32 or the convergent accelerates the gas taken by deflecting radially outwards. The sampling means may comprise a valve for regulating the flow of gas taken off, mounted for example at the orifice 26.
    [0007] Each blade has an aerodynamic shape in section (FIG. 4) and comprises an upper surface 40 and a lower surface 42 which are connected to each other, upstream, by an edge 44 of gas attack, and downstream, by a gas leakage edge 46. In known manner, the extrados 40 has a more pronounced profile (curved) than that of the intrados 42. In flight, a depression takes place on the upper surface 40, the pressure of the flow being lower than the static pressure and an overpressure occurs on the lower surface 42, the pressure of the flow being greater than the static pressure. Each of the blades 24 of the propeller 20 may be hollow and include an internal cavity 30 for the flow of gas withdrawn.
    [0008] The cavity 30 of each blade has an elongated cross section substantially along a rope connecting the leading edge 44 to the trailing edge 46 of the blade. As can be seen in FIG. 4, the sectional shape of the cavity is similar to the sectional profile of a wing or blade. However, this shape or profile is here advantageously reversed with respect to that of the blade 24.
    [0009] Thus, the cavity 30 comprises a first peripheral portion (delimited by a wall 62) comparable to a lower surface of a blade profile and located on the extrados side 40 of the blade, and a second peripheral portion (delimited by a partition 64) assimilable to an extrados of the blade profile and located on the side of the lower surface 42 of the blade. In the example shown, the wall 62 defines both the extrados 40 of the blade by its upper face and the aforementioned first peripheral portion of the cavity 30 by its lower face. The partition 64 defining, by its upper face, the second peripheral portion of the cavity 30, is independent against the wall of the blade defining its intrados 42. The wall 62 and the partition 64 are connected directly to their downstream end for forming a pointed end end 30, their upstream ends being connected together by a curved partition member 66 whose concavity is oriented downstream. This partition member 66 is spaced from the wall of the blade forming the leading edge 44. The partition 64 and the partition member 66 may be configured to stiffen the blade. The partition element 66 is preferably configured for rotating the withdrawn gas before it is ejected by said ejection means 36. These ejection means here comprise a longitudinal slot 36 which extends over substantially the entire length. of each blade. The slot 36 is here located on the upper surface 40 of the blade and communicates with the cavity 30 of this blade. It is generally located between the wall 62 and the partition element 66. Advantageously, the slot or outlet of each blade is located beyond the rope of the blade, at a point of twisting. One can imagine a valve or a shutter (mechanical device controlled according to the flight phase or the incidence of the aircraft) which modifies the position of the output of the Coandà effect cavity. The slot 36 is defined upstream, with respect to the air flow incident on the helix, by an annular exhaust lip 68 and downstream by a surface 70 of Coandà. By Coandà effect, the flow of gas ejected by the slot 36 on the surface 70 will flow along the surface of Coandà 38 and close to it 3036144 8 thereof. The flow of ejected gas shaves the profile, follows it and produces a surface depression (negative sign in Figure 4) accelerating virtues. This produces surrounding depressions in chains, which promote the entrainment and acceleration of the incident gas near the upper surface of the blade. The relative gas depression on the upper surface is reduced and more homogeneous than in the prior art. The arrows in FIG. 2 show gas entering the orifice 26 of the hub. The sample gas circulates in the chamber 28 and is then driven by the turbine 32 radially outwardly to feed the cavities 30 of the blades 24. The gas is rotated in the cavities 30 before being ejected onto the surfaces of Coandà 38 The gas flow portions are narrowed at their entrance into the slots 36 and at their exit slots. These restrictions create overpressures of gas flows ejected on the surfaces of Coandà. These ejections create zones of low pressure at the outlet of the slots, which results in a suction effect of the air of the incident gas. The ejected gas mixes with the incident gas and is guided by the surfaces of Coandà. The combination of entrainment and acceleration of the incident gas results in a high velocity of the gas passing through the propeller, which limits the detachment and detachment of the boundary layers on the operating blades. The invention described above is applicable to other types of turbomachine and for example to a fan propeller of a turbojet engine. 25
    权利要求:
    Claims (12)
    [0001]
    REVENDICATIONS1. Turbomachine propeller (20), comprising a hub (22) and an annular row of blades (24) extending substantially radially around said hub, characterized in that it comprises means (26) for sampling ambient gas in operation , and in that at least some of the blades comprise internal cavities (30) for circulating said sampled gas, as well as means (36) for ejecting said gas sampled from Coandà surfaces (38) of said certain blades.
    [0002]
    2. Propeller (20) according to claim 1, wherein the hub (22) comprises said sampling means (26).
    [0003]
    3. Propeller (20) according to claim 1 or 2, wherein said sampling means comprise at least one sampling port (26), for example on an axis (A) of rotation of the propeller or in the extension of this axis.
    [0004]
    The propeller (20) according to claim 1 or 2, wherein said hub (22) comprises an internal fluidic connection chamber (28) of the sampling means (26) to said inner cavities (30) of the blades (24).
    [0005]
    5. Propeller (20) according to claim 4, wherein a member, such as a centrifugal turbine (32) or a convergent, is mounted in said chamber (28) to drive the gas withdrawn radially outwardly.
    [0006]
    6. Propeller (20) according to one of the preceding claims, wherein said ejection means (36) are configured to eject gas on Coandà surfaces (38) of the extrados (40) of the blades (24).
    [0007]
    The propeller (20) of claim 6, wherein said ejecting means comprises ejection slots (36) in fluid communication with said cavities (30).
    [0008]
    8. Propeller (20) according to one of the preceding claims, wherein each of said cavities (30) has in section an elongate shape substantially along a rope connecting a leading edge (44) to a trailing edge ( 46) of the corresponding blade (24). 3036 144 10
    [0009]
    9. propeller (20) according to claim 8, wherein the sectional shape of each cavity (30) is comparable to the sectional profile of a blade and comprises a first peripheral portion comparable to a lower surface of said profile and located on the side of the extrados (40) of the corresponding blade 5, and a second peripheral portion comparable to an extrados of said profile and located on the side of the intrados (42) of said corresponding blade.
    [0010]
    The propeller (20) according to claim 9, wherein said first and second peripheral portions are connected together by a third curved peripheral portion which is located on the leading edge (44) side of said blade (24), and which is configured for rotating the withdrawn gas before it is ejected by said ejection means (36).
    [0011]
    11. Propeller (20) according to one of the preceding claims, wherein the sampling means (26) and / or said ejection means (36) comprise at least one valve for controlling the flow of gas withdrawn / ejected.
    [0012]
    12. A turbomachine, such as a turboprop, comprising at least one propeller (20) according to one of the preceding claims, which is preferably unsheathed. 20
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    同族专利:
    公开号 | 公开日
    FR3036144B1|2019-03-22|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    FR592393A|1925-01-29|1925-08-01|Aerial propeller|
    US1667506A|1927-02-10|1928-04-24|John S Bankrat|Propeller|
    FR835476A|1937-05-11|1938-12-22|Propeller refinements|
    US2638990A|1947-04-01|1953-05-19|Autogiro Co Of America|Aircraft sustaining rotor blade with airflow control|US10464668B2|2015-09-02|2019-11-05|Jetoptera, Inc.|Configuration for vertical take-off and landing system for aerial vehicles|
    US10875658B2|2015-09-02|2020-12-29|Jetoptera, Inc.|Ejector and airfoil configurations|
    US11001378B2|2016-08-08|2021-05-11|Jetoptera, Inc.|Configuration for vertical take-off and landing system for aerial vehicles|
    US11148801B2|2017-06-27|2021-10-19|Jetoptera, Inc.|Configuration for vertical take-off and landing system for aerial vehicles|
    法律状态:
    2016-05-25| PLFP| Fee payment|Year of fee payment: 2 |
    2016-11-18| PLSC| Search report ready|Effective date: 20161118 |
    2017-04-27| PLFP| Fee payment|Year of fee payment: 3 |
    2018-02-09| CD| Change of name or company name|Owner name: SAFRAN AIRCRAFT ENGINES, FR Effective date: 20170717 |
    2018-04-23| PLFP| Fee payment|Year of fee payment: 4 |
    2019-04-19| PLFP| Fee payment|Year of fee payment: 5 |
    2020-04-22| PLFP| Fee payment|Year of fee payment: 6 |
    2021-04-21| PLFP| Fee payment|Year of fee payment: 7 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1554169A|FR3036144B1|2015-05-11|2015-05-11|TURBOMACHINE PROPELLER|
    FR1554169|2015-05-11|FR1554169A| FR3036144B1|2015-05-11|2015-05-11|TURBOMACHINE PROPELLER|
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