Blade for an aircraft turbomachine

Abstract

Blade for an aircraft turbomachine comprising: a platform (10) having a duct surface (15), a blade (9, 22, 25) having a leading edge (11, 27, 28), a trailing edge (12, 29, 30), an intrados (13) and an extrados (14), the extrados (14) and the intrados (13) connecting the leading edge (11, 27, 28) and the trailing edge (12, 29, 30), a flow channel (18) extending into the platform (10) and having a suction outlet (19) which is configured to draw in an airflow downstream of the leading edge (11, 27, 28), the suction outlet (19) having an edge (23) which runs along the extrados (14) of the blade (9, 22, 25) from the leading edge (11, 27, 28), said channel (18) having an ejection mouth (21) configured to eject the airflow downstream of the trailing edge (12, 29, 30). Fig. 3.

Description

Title of the invention: Blade for an aircraft turbomachine technical field

[0001] The present exposition relates to the field of turbomachinery such as turboprops or turbojets.

[0002] More particularly, the invention relates to the field of turbines for aircraft turbomachinery, and more specifically to a blade for a distributor or for a moving wheel of a turbine. Previous technique

[0003] A conventional aircraft turbomachine turbine comprises one or more stages, each consisting of a distributor and a runner. The distributor comprises fixed blades connected at their radially external end to a casing and arranged circumferentially around a longitudinal central axis of the turbine to form a stator ring. The runner comprises a disk and blades connected to the disk at their radially internal end and arranged circumferentially around the disk. The distributor of a stage is configured such that a fluid flow entering that stage, typically comprising gases from a combustion chamber, is accelerated and deflected by the stator blades towards the blades of the runner of that stage, thereby causing the runner to rotate about the longitudinal central axis.

[0004] In general, each distributor and turbine runner blade comprises a blade extending radially from a platform and radially defining a circumferential portion of an annular primary gas flow duct in which the blade extends. The fluid passing through the turbine flows mainly in this primary duct.

[0005] During the operation of a conventional turbine, the interaction of the fluid with the distributors and the moving wheels produces vortices at the level of the blade platforms, forming so-called "secondary" flows.

[0006] In particular, low-pressure turbine blades generate so-called "secondary" flows at the blade root and tip. These vortices arise primarily from the fact that the local flow at the root and tip upstream of the blade has a low velocity. These vortices are characterized, for example, by two vortices separating into an intrados vortex and an extrados vortex. The intrados vortex migrates, due to pressure, towards the extrados of the adjacent blade, thus generating a vortex secondary flow that is not oriented in the direction of the main flow. The extrados vortex, for its part, runs along the extrados of the blade and disturbs its boundary layer, potentially leading to blade separation.

[0007] These secondary flows in the form of vortex structures generate significant losses in the turbine. These losses reduce the efficiency of the turbomachine and increase the engine's kerosene consumption.

[0008] There is therefore a need to provide blades that reduce secondary flows in order to decrease the effects of pressure losses and improve the efficiency of the turbomachine.

[0009] The invention aims to remedy at least in part the disadvantages mentioned above. Summary of the invention

[0010] One idea underlying the invention is to reduce vortex flows in the blade, particularly upstream of the blade. To this end, one idea of ​​the invention is to largely, and preferably completely, draw in a horseshoe-shaped secondary flow forming near the leading edge of a blade. Thus, one idea underlying the invention is to selectively draw in the vortices associated with the secondary flows formed in the turbine.

[0011] To this end, the invention provides a blade for an aircraft turbomachine intended to be mounted centered on an axis and comprising: - a platform presenting a vein surface, - a blade extending radially from the axis from the surface of the vein, the blade having a leading edge, a trailing edge, an intrados and an extrados, the extrados and intrados connecting the leading edge and the trailing edge, - a flow channel extending into the platform, said channel having a suction inlet opening onto the surface of the duct and configured to draw in an airflow downstream of the leading edge, the suction inlet having an edge running along the upper surface of the blade from the leading edge, said channel having an ejection inlet configured to eject the airflow downstream of the trailing edge and the channel being configured so that the airflow can pass through the channel.

[0012] The suction inlet, having an edge along the upper surface of the blade, allows the upper surface component of the secondary flow to be drawn into the channel; that is, the horseshoe-shaped component of the secondary flow forming on the upper surface of the blade. In particular, the edge along the upper surface ensures that the upper surface component of the secondary flow does not adhere to the upper surface but is drawn into the channel via the suction inlet and therefore does not disturb the boundary layer of the blade.

[0013] According to different embodiments, the blade for an aircraft turbomachine according to the invention may comprise one or more of the following features, alone or in combination.

[0014] According to one embodiment, the vein surface develops circumferentially around the axis, typically the longitudinal axis of the turbomachine when the element is integrated into a turbomachine.

[0015] According to one embodiment, the platform is intended to delimit a flow channel of the through flow, said through flow flowing in a direction from the leading edge to the trailing edge of the blade.

[0016] According to one embodiment, the platform is an internal platform, the vein surface being adapted to radially delimit inwards a primary flow vein.

[0017] According to one embodiment, the edge of the suction nozzle opens circumferentially next to the leading edge of the blade and is generally complementary in shape to the upper surface of the blade. In other words, the edge of the suction nozzle extends from the leading edge parallel to the upper surface. For example, the edge of the suction nozzle and the upper surface are complementary in shape such that a minimum distance between said edge of the suction nozzle and the upper surface is constant along said edge. Thus, the edge of the suction nozzle effectively follows the upper surface and can therefore satisfactorily draw in the upper surface component of the secondary flow.

[0018] Preferably the circumferential distance separating the extrados from the edge of the suction mouth is zero, that is to say reduced to the minimum imposed by the mechanical manufacturing constraints, typically the distances related to manufacturing tolerances and / or necessary for the tooling used to manufacture the blade.

[0019] According to one embodiment, the suction inlet opens upstream relative to the leading edge of the blade. Typically, the suction inlet extends beyond the leading edge away from the trailing edge along an axis connecting the leading edge and the trailing edge.

[0020] According to one embodiment, the blade has a blade chord length corresponding to the distance connecting the leading edge of the blade and the trailing edge of the blade along a blade axis connecting the leading edge of the blade and the trailing edge of the blade, the intake opening extending upstream of the leading edge of the blade along the blade axis. Preferably, the intake opening extends upstream of the leading edge of the blade over a distance less than or equal to 10% of the blade chord length. The leading edge is the edge impacted first by the throughflow. Thus, from a geometric point of view, the leading edge is the upstream point of the blade where the radius of curvature of the blade surface is minimal. Similarly, The trailing edge is the downstream point of the blade where the radius of curvature of the blade surface is minimal.

[0021] According to one embodiment, the blade has a blade chord length corresponding to the distance connecting the leading edge of the blade and the trailing edge of the blade along a blade axis connecting the leading edge of the blade and the trailing edge of the blade, the suction mouth extending along the extrados of the blade over a distance less than half the length of the blade chord length.

[0022] According to one embodiment, the suction mouth extends along the extrados of the blade over a distance, along the axis connecting the leading edge of the blade and the trailing edge of the blade, less than half the blade chord length, i.e. less than or equal to 50% of the blade chord length.

[0023] This arrangement of the suction nozzle at the leading edge of the blade is particularly advantageous because vortices form early in the duct or even upstream of the blade. This range of suction nozzle positioning thus ensures the complete capture of the upper surface component of the secondary flow.

[0024] According to one embodiment, the blade comprises a first blade and a second blade, each blade extending radially with respect to the axis (X) from the vein surface, each blade having a leading edge, a trailing edge, an intrados and an extrados, the extrados and the intrados connecting the leading edge and the trailing edge, the suction opening being a first suction opening, the intrados of the second blade and the extrados of the first blade being arranged circumferentially opposite each other, the channel having a second suction opening, said second suction opening onto the vein surface circumferentially between the intrados of the second blade and the extrados of the first blade.

[0025] More specifically, the second suction inlet opens onto the duct surface circumferentially between the first suction inlet and the lower surface of the second blade. This second suction inlet is configured to draw the airflow downstream of the leading edge of the second blade.

[0026] According to one embodiment, the second suction opening opens circumferentially at the right, i.e. axially at the same level, of the leading edge of the second blade.

[0027] Such an element for an aircraft turbomachine allows for the intake of both components, and advantageously the entirety, of the secondary flow. Indeed, as explained above, the first intake nozzle allows for the intake of the upper surface component of the horseshoe-shaped secondary flow formed by the first blade. Similarly, the second intake nozzle allows for the intake of the lower surface component of the secondary flow forming on the lower surface of the second blade and flowing between the intrados of the second blade and the extrados of the first blade.

[0028] The suction of both components of the secondary flow also reduces losses in the blades arranged downstream in the turbomachine. Indeed, suction of the two components of the secondary flow reduces the angle and velocity distortion generated by said secondary flows. In other words, the flow impacting a blade arranged downstream in the turbomachine is cleaner and less disturbed, thus reducing pressure losses and improving the aerodynamic efficiency of the turbines.

[0029] According to one embodiment, the channel comprises a central portion, a first suction portion, and a second suction portion, said first and second suction portions opening into the central portion. The first suction portion is configured so that a fluid entering the first suction port can reach the central portion, and the second suction portion is configured so that a fluid entering the second suction port can allow a fluid entering the second suction port to reach the central portion. Typically, the first suction portion connects the first suction port to the central portion, and the second suction portion connects the second suction port to the central portion. The central portion opens at the discharge port.

[0030] Preferably, the discharge outlet opens downstream of the suction outlet(s). However, the channel may have one or more discharge outlets, which may be arranged in numerous locations to allow the evacuation of the flow collected by the suction outlet(s).

[0031] According to one embodiment, the discharge nozzle opens onto the surface of the stream downstream of the suction nozzle(s), preferably close to the trailing edge of the blade(s). For example, this discharge nozzle opens into an inter-blade space.

[0032] According to one embodiment, the channel includes an ejection outlet opening upstream of a rotating wheel. Thus, the flow reinjected via the ejection outlet works through the rotating wheel downstream and, consequently, provides mechanical energy to the rotor.

[0033] According to one embodiment, the channel has an ejection mouth opening outside the vein at the level of the purge.

[0034] According to one embodiment, the channel includes an ejection mouth opening into a cavity of the turbomachine, for example a so-called "by-pass" cavity.

[0035] According to one embodiment, the channel includes an ejection mouth which opens into an inter-lick space.

[0036] With such an ejection nozzle, the suction movement of the channel from the leading edge to the trailing edge downstream of the trailing edge results from the pressure gradient between the suction zone at the suction nozzle(s), upstream of the blade, and the ejection zone at the ejection nozzle. Indeed, regardless of the ejection zone(s) chosen for the channel's ejection nozzle, the pressure is significantly higher in the upstream zone of the blade than in the ejection zone. This results in a natural movement of the fluid between these two zones that does not require the intervention of external systems such as a mechanical or electrical suction system. In other words, the suction system provided by the invention is a passive system, which constitutes a significant advantage compared to an active system requiring an external system.Advantageously, such an ejection port can allow reintroduction losses to be mixed with pellet losses.

[0037] According to one embodiment, the platform comprises a second surface, radially opposite to the vein surface, from which a foot extends radially inward, said foot having a radially internal end, a sealing element being arranged on said radially internal end. Such a sealing element is, for example, an abradable material or the ridges of a dynamic seal, said dynamic seal being intended to delimit an inter-ridge cavity.

[0038] According to one embodiment, the channel extends into said foot, the ejection mouth opening into the inter-lick cavity.

[0039] According to an alternative embodiment, the second surface of the platform delimits a purging cavity downstream of the foot, the ejection mouth of the channel opening at the level of said second surface into said purging cavity.

[0040] Preferably, the suction inlet(s) are oriented along the axes of deflection of the corresponding secondary flow components. Thus, the first suction inlet is advantageously arranged along an axis of deflection of the upper surface component of the secondary flow developing on the upper surface of the first blade. Similarly, the second suction inlet is arranged along an axis of deflection of the lower surface component of the secondary flow developing on the lower surface of the second blade.

[0041] According to one embodiment, the first suction mouth opens onto the vein surface between a first axis and a second axis, the first axis connecting the leading edge of the first blade and the leading edge of the second blade and the second axis connecting the leading edge of the first blade and the trailing edge of the second blade.

[0042] According to one embodiment, the first suction inlet and the second suction inlet open circumferentially opposite each other, that is to say axially at the same level so that the first suction opening and the second suction opening are both at least partially arranged in a common plane perpendicular to the axis.

[0043] According to one embodiment, the second suction mouth opens onto the vein surface between the first axis and a third axis, said third axis connecting the leading edge of the second blade and the trailing edge of the first blade.

[0044] Thus, according to a preferred embodiment, the vein surface has an air inlet zone delimited by a first axis, a second axis and a third axis, the first axis connecting the leading edge of the first blade and the leading edge of the second blade, the second axis connecting the leading edge of the first blade and the trailing edge of the second blade, the third axis connecting the leading edge of the second blade and the trailing edge of the second blade, the first suction outlet opening onto said air inlet zone and / or the second suction outlet opening onto said air inlet zone.

[0045] Such an orientation of the suction mouths ensures their positioning in the direction of the axes of deviation of the components of the secondary flow, thus allowing the suction of the secondary flow in its entirety.

[0046] According to one embodiment, the suction opening(s) have an aerodynamically shaped form.

[0047] Typically, such an aerodynamically shaped form has rounded edges and a continuous border, without angles or corners. Thus, the suction inlet(s) may, for example, have an oblong shape, a circular shape, an ovoid shape, a "teardrop" shape, or any other aerodynamically shaped form.

[0048] Such an aerodynamically designed shape without edges or corners limits disturbances in the flow.

[0049] Similarly, the channel is preferably smooth. Such a smooth channel limits pressure losses in the channel.

[0050] According to one embodiment, the channel develops from the suction port(s) with a progressive slope relative to the vein surface.

[0051] Such a gradual slope makes it possible to avoid flow separation in the channel at the suction inlet and thus to reduce pressure losses.

[0052] Similarly, the channel has an internal surface with gradual changes in direction in order to avoid pressure losses in the channel.

[0053] The channel also has a gradual slope at the ejection mouth in order to avoid mixing losses at the channel outlet.

[0054] According to one embodiment, the turbomachine blade is a turbomachine stage distributor, that is to say a stator element, with fixed blades in the turbomachine. According to one embodiment, the turbomachine blade is a moving wheel of the turbomachine, that is to say a rotor element.

[0055] The invention also provides a turbine for a turbomachine comprising: - a distributor comprising at least one blade for an aircraft turbomachine such as above, and / or - a movable wheel comprising at least one blade for an aircraft turbomachine such as above.

[0056] The invention also provides a turbomachine comprising a turbine such as above. Brief description of the drawings

[0057] The accompanying drawings are schematic and are intended primarily to illustrate the principles of the exposition. On these drawings, from one figure to another, identical elements (or parts of elements) are identified by the same reference symbols. [Fig.1] [Fig.1] is a schematic cross-sectional view of an aircraft turbomachine; [Fig.2] [Fig.2] represents a schematic perspective view of a portion of a turbomachine element comprising two blades; [Fig.3] Fig.3 illustrates a partial schematic view of the top of a turbomachine element according to the invention; [Fig.4] Fig.4 schematically illustrates a cross-sectional view of a blade according to different channel positioning variants. Description of the implementation methods

[0058] The aforementioned features and advantages, as well as others, will become apparent from the following detailed description of examples of embodiments of the aircraft turbomachine element according to the invention. This detailed description refers to the accompanying drawings.

[0059] In the present description, the terms "axial", "radial", "tangential", "internal", "external" and their derivatives are defined with respect to the main axis of the turbomachine. Furthermore, the terms "upstream" and "downstream" are defined with respect to the airflow within the turbomachine.

[0060] Fig. 1 represents, in cross-section along a vertical plane passing through its main axis X, a turbofan engine 1. This turbofan engine 1 comprises, from upstream to downstream along the circulation of the airflow G, a fan 2, a low-pressure compressor 3, a high-pressure compressor 4, a combustion chamber 5, a high-pressure turbine 6, and a low-pressure turbine 7.

[0061] In a manner known per se, the low-pressure turbine 7 comprises a plurality of stages, each stage including a distributor and a runner. The runners of said stages are mounted axially to one another by annular flanges and form the rotor of the low-pressure turbine 7. The distributors are connected to a housing to form the stator of the low-pressure turbine.

[0062] Each distributor comprises a plurality of blades circumferentially distributed around the longitudinal axis X of the turbomachine 1. Each movable wheel comprises on its side a disk and a plurality of blades circumferentially distributed around the longitudinal axis X.

[0063] Figure 2 schematically illustrates two blades 8, each comprising a blade 9 and a platform 10, these blades 8 being circumferentially adjacent to each other. Figure 2 shows more particularly a radially internal portion of the blade 9 and the platform 10 of each of the blades 8. The blade 9 of each blade 8 comprises a leading edge 11, a trailing edge 12, an intrados 13, and an extrados 14. The platform 10 of each blade 8 has a radially external surface 15, also called the duct surface 15, which delimits a circumferential portion of an annular primary conduit in which a fluid flows in a direction from the leading edge 11 to the trailing edge 12 of the blades 9.

[0064] Given the typical viscosity of the fluid flowing in the primary duct of a turbine, its flow along the runner surface 15 exhibits a velocity gradient such that, in the vicinity of this runner surface 15, the velocity of a fluid layer is lower the closer this layer is to the runner surface 15. The fluid flowing in the primary duct is also subjected to a pressure gradient directed, in this example, from the lower surface 13 of one of the blades 9 towards the upper surface 14 opposite the circumferentially adjacent blade 9. The pressure gradient is generally sufficient to deflect the fluid layers flowing near the runner surface 15.

[0065] This results in the appearance of different types of vortices. In particular, it results in a type of vortex, known as a "horseshoe" vortex, which takes the form of two counter-rotating branches distributed on either side of the blades 9. Thus, the leading edge 11 of a blade leads to the creation of a secondary flow comprising a vortex on the lower surface, called the lower surface component 16 of the horseshoe secondary flow, and a vortex on the upper surface, called the upper surface component 17 of the horseshoe secondary flow. The lower surface component 16 migrates by pressure effect towards the upper surface 14 of the blade 9. The upper surface component 17, for its part, follows the upper surface 14 of the blade 9 and disturbs the boundary layer of the upper surface 14.

[0066] Such secondary flows, which typically occur at the root and tip of the blades 9, are not oriented in the direction of the main flow of the fluid passing through the primary conduit. These secondary flows consequently entail a reduction in efficiency and an increase in kerosene consumption of the turbomachine.

[0067] Figure 3 illustrates a suction channel 18 according to the invention in order to suction these secondary flows and reduce pressure losses in the primary conduit.

[0068] The channel 18 illustrated in [Fig. 3] comprises a first suction port 19, a second suction port 20, and an ejection port 21. The first suction port 19 and the second suction port 20 open onto the vein surface 15 of the platform 10 between the two circumferentially adjacent blades 9. The ejection port 21 opens onto the vein surface 15 downstream of the first suction port 19 and the second suction port 20.

[0069] The first suction inlet 19 extends from a first leading edge 27 on the upper surface 14 of a first blade 22. This first suction inlet 19 has an edge 23 that runs along the upper surface 14 of the first blade 22. The distance separating the edge 23 of the first suction inlet 19 from the upper surface 14 of the first blade 22 is ideally zero or reduced to a minimum. In other words, the circumferential distance separating said edge 23 from the upper surface 14 is as small as possible. Thus, in the example illustrated in [Fig. 3], this edge 23 of the first suction inlet 19 is separated circumferentially from the upper surface 14 of the first blade 22 by only the distance imposed by manufacturing tolerances and / or the tools necessary for manufacturing the blade 8.This first suction opening 19 is arranged at the level of the first leading edge 27 and on the extrados side 14 of the first blade 22 and extends from the first leading edge 27 of the first blade 22 along the extrados 14 of said first blade 22. .

[0070] This first suction opening 19 has a teardrop shape, one end of the first suction opening 19 arranged opposite the first leading edge 27 of the first blade 22 forming a rounded point 24. Moving away from this rounded point 24, the first suction opening 19 widens and has, at a second end opposite the first end, a rounded shape with concavity turned towards the rounded point 24.

[0071] Because the edge 23 of the first suction mouth 19 runs along the extrados 14 of the first blade 22, the extrados component 17 formed by the first leading edge 27 of the first blade 22 is entirely sucked into the channel 18 via the first suction mouth 19.

[0072] The second suction mouth 20 is arranged between the first suction mouth 19 and the intrados 13 of a second blade 25 circumferentially adjacent to the first blade 22, the intrados 13 of this second blade 25 being circumferentially opposite the extrados 14 of the first blade 22.

[0073] This second suction opening 20 has an upstream edge 26 extending along an axis connecting the first leading edge 27 formed by the first blade 22 and a second leading edge 28 formed by the second blade 25. The second suction opening 20 is arranged on the passage of the lower surface component 16 of the horseshoe secondary flow formed by the second blade 25 so as to suction said lower surface component 16.

[0074] Thus, the first suction mouth 19 and the second suction mouth 20 jointly allow the two components, intrados 16 and extrados 17, of the horseshoe secondary flow formed by the primary flow in the primary conduit to be aspirated.

[0075] The first suction mouth 19 and the second suction mouth 20 form the respective inlets of a first suction portion 43 and a second suction portion 44 of the channel 18 within the platforms 10. These suction portions 43 and 44 have progressive slopes so as to allow suction of the intrados 16 and extrados 17 components without pressure loss and avoiding detachment of said flow in the channel 18.

[0076] Furthermore, these suction portions of the channel 18 join in the platform 10 so as to jointly form an ejection portion 45, or central portion 45, of the channel 18. This ejection portion 45 terminates with the ejection mouth 21 allowing the flow aspirated in the channel 18 to be evacuated via the suction mouths 19 and 20.

[0077] The channel 18 has the smoothest possible internal surface in order to avoid disturbances and therefore pressure losses that may result in the channel 18.

[0078] The internal surface of the channel 18 also has the smoothest possible orientation, i.e., without any abrupt changes in its orientation, in order to also avoid pressure losses. In the example illustrated in [Fig. 3], the channel 18 extends within the platform 10 in an orientation substantially parallel to the orientation of the intrados 13 and extrados 14 between which the channel 18 is circumferentially arranged.

[0079] The ejection mouth 21 opens onto the surface of the vein 15 downstream of a first trailing edge 29 formed by the first blade 22 and a second trailing edge 30 formed by the second blade 25. Thus, the only pressure difference between upstream of the blades 22 and 25 and downstream of said blades 22 and 25 is sufficient to generate a pressure gradient sufficient to draw in via the suction mouths 19 and 20 the intrados 16 and extrados 17 components of the horseshoe secondary flow.

[0080] Similar to the suction portions of the channel 18, the ejection portion 45 has a progressive slope at the ejection mouth 21 in order to avoid pressure losses in the flow through the channel 18.

[0081] The first suction inlet 19 is advantageously arranged so as to be aligned with the extrados component 17 formed by the first blade 22. Thus, The first suction opening 19 is advantageously arranged to open onto the vein surface 15 between, on the one hand, a first axis 31 connecting the first leading edge 27 to the second leading edge 28 and, on the other hand, a second axis 32 connecting the first leading edge 27 to the second trailing edge 30. In addition, the first suction opening 19 can develop axially up to mid-chord 33 of the blade chord distance of the first blade 22.

[0082] The horseshoe secondary flow forming mainly at the leading edge 27, such an arrangement of the first suction mouth 19 ensures good suction of the extrados component 17 of said horseshoe secondary flow.

[0083] Similarly, the second suction inlet 20 is arranged to open onto the surface of the vein 15 between, on the one hand, the first axis 31 connecting the first leading edge 27 to the second leading edge 28 and, on the other hand, a third axis 34 connecting the second leading edge 28 and the second trailing edge 30. The second suction inlet 20 also extends axially to mid-chord 42 of the blade chord distance of the second blade 25. This arrangement of the second suction inlet 20 ensures good suction of the lower surface component 16 of the horseshoe secondary flow.

[0084] Thus, preferably, the vein surface 15 has a zone 46 delimited by the first axis 31, the second axis 32 and the third axis 34, the first suction mouth 19 and the second suction mouth 20 both opening into said zone 46 of the vein surface 15.

[0085] However, secondary flow can also form upstream of the leading edge 11. Thus, the first suction outlet 19 can advantageously be arranged to open onto the duct surface 15 upstream of the first leading edge 27. Typically, the first suction outlet 19 can be arranged upstream of the first leading edge 27 over a distance less than or equal to 10% of the blade chord length of the first blade 22 along a fourth axis 35 connecting the first leading edge 27 and a first trailing edge 29 of the first blade 22. In such a case, the first axis 31 connects the second leading edge 28 to the most downstream point of the first suction outlet 19 along the fourth axis 35.

[0086] In the examples above, the discharge nozzle 21 is arranged to open onto the flow surface 15 downstream of the blades 22 and / or 25. However, this discharge nozzle 21 can open at other locations in the turbomachine. Figure 4 schematically illustrates examples of possible variants for the arrangement of the discharge nozzle 21 according to the invention.

[0087] On this [Fig. 4], the platform 10 comprises a radially internal surface 36, opposite the vein surface 15. A foot 37 extends radially inwards from this internal surface 36. This foot 37 has on one radially internal end a sealing element 38, for example an abradable coating or the ribs of a dynamic seal. This sealing element 38 is intended to delimit an inter-rib cavity 39.

[0088] According to a first variant, the channel 18 extends into the foot 37, so that the ejection mouth 21 opens at the level of the inter-lick cavity 39.

[0089] According to a second variant, the channel 18 extends into the platform 10 so that the ejection mouth 21 opens at the level of the purge 40.

[0090] According to a third embodiment, the channel 18 extends into the platform 10 so that the ejection mouth 21 opens onto the internal surface 36 of the platform 10 in a "by-pass" cavity 41.

[0091] In all these variants, the pressure difference between the suction mouths 19 and 20 and the ejection mouth 21 is sufficient to generate a pressure gradient capable of allowing the aspiration of the horseshoe secondary flow into the channel 18, without requiring an additional suction system.

[0092] Although the present invention has been described with reference to specific embodiments, it is evident that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various embodiments illustrated / mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than a restrictive sense.

Claims

Demands

1. A blade for an aircraft turbomachine intended to be mounted centered on an axis (X) and comprising: - a platform (10) having a duct surface (15), - a blade (9, 22, 25) extending radially from the axis (X) from the duct surface (15), the blade (9, 22, 25) having a leading edge (11, 27, 28), a trailing edge (12, 29, 30), an intrados (13) and an extrados (14), the extrados (14) and the intrados (13) connecting the leading edge (11, 27, 28) and the trailing edge (12, 29, 30), - a flow channel (18) extending into the platform (10), said channel (18) having a suction inlet (19) which opens onto the vein surface (15) and which is configured to draw in an airflow downstream of the leading edge (11, 27, 28), the suction mouth (19) having an edge (23) which runs along the extrados (14) of the blade (9, 22, 25) from the leading edge (11, 27, 28),said channel (18) having an ejection outlet (21) configured to eject the airflow downstream of the trailing edge (12, 29, 30) and the channel (18) being configured so that the airflow can pass through the channel (18).

2. Blade for an aircraft turbomachine according to claim 1, wherein said edge (23) of the suction mouth (19) opens circumferentially next to the leading edge (11, 27, 28) of the blade (9, 22, 25) and has an overall complementary shape with the extrados (14) of the blade (9, 22, 25).

3. Blade for an aircraft turbomachine according to claim 1 or 2, wherein the suction mouth (19) opens upstream with respect to the leading edge (27) of the blade (9, 22, 25).

4. A blade for an aircraft turbomachine according to any one of claims 1 to 3, having a blade chord length corresponding to the distance connecting the leading edge (27) of the blade (9, 22, 25) and the trailing edge (29) of the blade (9, 22, 25) along a blade axis (35) connecting the leading edge (27) of the blade (9, 22, 25) and the trailing edge (29) of the blade (9, 22, 25), wherein the intake outlet (19) extends upstream of the leading edge (27) of the blade (9, 22, 25) along the blade axis (35), and wherein the outlet suction (19) extends upstream of the leading edge (27) of the blade (9, 22, 25) over a distance less than or equal to 10% of the blade chord distance.

5. Blade for an aircraft turbomachine according to any one of claims 1 to 4, having a blade chord length corresponding to the distance connecting the leading edge (27) of the blade (9, 22, 25) and the trailing edge (29) of the blade (9, 22, 25) along a blade axis (35) connecting the leading edge (27) of the blade (9, 22, 25) and the trailing edge (29) of the blade (9, 22, 25), in which the suction mouth (19) extends along the upper surface (14) of the blade (9, 22, 25) over a distance less than half the length of the blade chord length of the blade (9, 22, 25).

6. A blade for an aircraft turbomachine according to any one of claims 1 to 5, comprising a first blade (22) and a second blade (25), each blade (22, 25) extending radially about the axis (X) from the runner surface (15), each blade (9, 22, 25) having a leading edge (11, 27, 28), a trailing edge (12, 29, 30), an underside (13) and an upper surface (14), the upper surface (14) and the underside (13) connecting the leading edge (11, 27, 28) and the trailing edge (12, 29, 30), and wherein the intake is a first intake (19), the underside (13) of the second blade (25) and the upper surface (14) of the first blade (22) being arranged circumferentially opposite each other, and in which the channel (18) has a second aspiration mouth (20), said second aspiration mouth (20) opening onto the vein surface (15) circumferentially between the first aspiration mouth (19) and the intrados (13) of the second blade (25),said second suction inlet (20) being configured to draw in the airflow downstream of the leading edge (28) of the second blade (25).

7. A blade for an aircraft turbomachine according to claim 6, wherein the channel (18) comprises a central portion (45), a first suction portion (43), and a second suction portion (44), said first suction portion (43) and second suction portion (44) opening into the central portion (45), the first suction portion (43) being configured such that a fluid entering the first suction outlet (19) can reach the central portion (45) and the second portion suction (44) being configured so that a fluid entering the second suction mouth (20) can allow a fluid entering the second suction mouth (20) to reach the central portion (45).

8. Blade for an aircraft turbomachine according to claim 6 or 7, wherein the second suction outlet (20) opens circumferentially at the leading edge (28) of the second blade (25).

9. Blade for an aircraft turbomachine according to any one of claims 6 to 8, wherein the first suction outlet (19) and the second suction outlet (20) open circumferentially at the right of each other.

10. A blade for an aircraft turbomachine according to any one of claims 6 to 9, wherein the duct surface (15) has an air inlet area (46) delimited by a first axis (31), a second axis (32) and a third axis (34), the first axis (31) connecting the leading edge (27) of the first blade (22) and the leading edge (28) of the second blade (25), the second axis (32) connecting the leading edge (27) of the first blade (22) and the trailing edge (30) of the second blade (25), the third axis (34) connecting the leading edge (28) of the second blade (25) and the trailing edge (30) of the second blade (25), and wherein the first suction outlet (19) and / or the second suction outlet (20) opens onto said inlet area of air (46).

11. Turbine for a turbomachine comprising - a distributor including at least one blade for an aircraft turbomachine according to any one of claims 1 to 10, and / or - a moving wheel including at least one blade for an aircraft turbomachine according to any one of claims 1 to 10.

12. Turbomachine comprising a turbine according to claim 11.

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