Wall equipped with a cooling orifice having a diffusion portion with a triangular cross-section

Abstract

The invention relates to a turbomachine component such as a blade, comprising a wall having at least one cooling orifice (26) and a metering portion (32) and a flared diffusion portion (33). According to the invention, the diffusion portion (33) comprises a central edge (40) forming a bottom of the diffusion portion (33) oblique to a flow axis (A2) of the cooling orifice (26). Figure for the abstract: Fig. 4

Description

Title of the invention: Wall equipped with a cooling orifice having a diffusion portion with a triangular cross-section. Technical field

[0001] The invention relates to the field of aircraft turbomachinery and to the field of air film cooling of components such as turbine blades. Prior art

[0002] A conventional turbomachine turbine comprises at least one distributor and at least one moving wheel, each having blades exposed to hot combustion gases.

[0003] In order to preserve the mechanical integrity of the blades, it is known to introduce fresh air into them and to provide them with cooling orifices configured to direct some of this fresh air onto their external surface so as to form a thermal protection film.

[0004] A conventional blade cooling orifice includes a metering portion, also called a "calibrating portion", generally cylindrical, which allows adjustment of the quantity of air passing through this orifice and a flared diffusion portion improving the distribution of the cooling air on the external surface of the blade.

[0005] The flow of fresh air exiting a conventional cooling orifice is exposed to counter-rotating vortices that form at the outlet section of this orifice, resulting in separation of the fresh air flow and the ingestion of hot gases into the cooling orifice. This leads to a reduction in cooling efficiency. Description of the invention

[0006] An object of the invention is to provide a cooling orifice geometry that increases cooling efficiency.

[0007] To this end, the invention relates to a component for a turbomachine, comprising a wall having a first surface and a second surface opposite with respect to the first surface, the wall comprising at least one cooling orifice which has a flow axis and which is configured to convey a cooling fluid from the first to the second surface through the wall, the cooling orifice comprising a metering portion which opens onto the first surface and a diffusion portion which opens onto the second surface, the diffusion portion being delimited by a flared surface.

[0008] According to the invention, the flared surface includes a central edge forming a bottom of the diffusion portion.

[0009] Thus, in sections formed by a plane normal to the flow axis and intersecting the central edge, the point on the central edge passing through this plane is the point furthest from the flow axis among all the points of the third surface contained in this section.

[0010] The central edge thus makes it possible to progressively move away a fraction of the cooling fluid from the flow axis and from the main areas of influence of the counter-rotating vortices forming at the outlet section of the cooling orifice.

[0011] On either side of the central edge, the flared surface extends to form surface parts called flow guide portions.

[0012] Such guide portions allow a fraction of the cooling fluid to be guided towards the outlet through the bottom of the diffusion portion.

[0013] Given the orientation of the central edge and the fact that it forms a bottom of the diffusion portion, the guiding portions make it possible to reduce the risk of ingestion of hot gases, in particular at the downstream end of the bottom of the diffusion portion, by progressively moving the counter-rotating vortices away from the bottom of the diffusion portion.

[0014] The invention thus makes it possible to improve the efficiency of the cooling.

[0015] Preferably, the central edge is rounded, that is to say, it may have a radius of curvature.

[0016] In one embodiment, the flared surface comprises two lateral edges which delimit the flared surface laterally on either side and each define with the central edge a portion of flow guidance, in particular one of the aforementioned guidance portions.

[0017] Alternatively, the flared surface may be devoid of lateral edges, in which case the guiding portions may, for example, join each other, via a curved surface portion, without surface discontinuity.

[0018] According to a first embodiment, the guiding portions are flat.

[0019] According to this first variant, the diffusion portion has, in a plane orthogonal to the flow axis, a section having a part forming a "V", defining a triangular half-section having a vertex formed by the central edge.

[0020] According to a second embodiment, the guide portions are curved, for example having a convex or concave shape.

[0021] According to this second variant, the diffusion portion may present, in a plane orthogonal to the flow axis, a section having a part forming a deformed "V", defining a semi-section of quasi-triangular shape having a vertex formed by the central edge.

[0022] When the third surface includes lateral edges as defined above, these are preferably inclined with respect to the central edge.

[0023] The lateral edges can also be oriented with respect to the flow axis so that each of them moves away from the flow axis in a direction from the first surface to the second surface.

[0024] It is preferred that the central edge have a length greater than that of each of the lateral edges.

[0025] This makes it possible to accentuate the phenomenon of progressive distancing of the counter-rotating vortices from the bottom of the diffusion portion and corresponding distancing of the channeled fluid from the bottom of the diffusion portion of the area of ​​influence of such vortices.

[0026] Lateral edges shorter than the central edge also help to reduce the lateral ingestion of hot gases in the diffusion portion.

[0027] In one embodiment, the lateral edges intersect the central edge in an inlet section of the diffusion portion.

[0028] In another embodiment, the lateral edges do not intersect the central edge.

[0029] The diffusion portion is preferably lobe-free.

[0030] In one embodiment, the flared surface is symmetrical with respect to a plane passing through the central edge.

[0031] This plane can be a plane of symmetry for the diffusion portion as a whole and / or for the flared surface and / or for the lateral edges.

[0032] The invention also relates to a turbine for a turbomachine, comprising a moving wheel, a distributor and at least one component as defined above forming a blade of the moving wheel or of the distributor.

[0033] The invention also relates to a combustion chamber for a turbomachine, comprising at least one component as defined above forming a wall of the combustion chamber.

[0034] The invention also relates to a turbomachine for an aircraft such as an airplane or a helicopter, comprising such a turbine and / or such a combustion chamber.

[0035] According to another aspect, the invention relates to a method for manufacturing a component as defined above.

[0036] In one embodiment, the process includes an electro-erosion machining step of the diffusion portion.

[0037] In one embodiment, the process includes a laser treatment step of the diffusion portion, in particular of the flared surface.

[0038] Other advantages and features of the invention will become apparent from the following detailed, non-limiting description. Brief description of the drawings

[0039] The detailed description that follows refers to the accompanying drawings in which:

[0040] [Fig-1] is a schematic longitudinal cross-sectional view of a propulsion assembly aircraft;

[0041] [Fig.2] is a schematic perspective view of a movable wheel blade of a turbine of the propulsion assembly of the [Fig.l];

[0042] [Fig.3] is a schematic cross-sectional view of a wall comprising a cooling orifice according to a first embodiment of the invention;

[0043] [Fig.4] is a schematic perspective view of a surface delimiting an orifice of cooling according to the first embodiment of the invention;

[0044] [Fig.5] is a schematic perspective view of a diffusion portion of the cooling orifice of [Fig.4];

[0045] [Fig.6] is a schematic perspective view of the diffusion portion of the cooling orifice of [Fig.4];

[0046] [Fig.7] is a schematic perspective view of a surface delimiting a portion diffusion from a cooling orifice according to a second embodiment of the invention;

[0047] [Fig.8] is a schematic view of concave surface parts forming guide portions of a cooling orifice according to the invention;

[0048] [Fig.9] is a schematic view of convex surface parts forming portions guiding a cooling orifice according to the invention;

[0049] [Fig. 10] is a schematic view of a flared surface of a cooling orifice diffusion portion according to the invention, showing a rounded central edge. Detailed description of implementation methods

[0050] Fig. 1 shows an aircraft propulsion assembly 1 (not shown) comprising a turbomachine 2 and a nacelle 3 extending about a central longitudinal axis AL

[0051] Subsequently, the terms "upstream" and "downstream" are defined relative to an SI direction of gas flow through the propulsion assembly 1 along the AL axis

[0052] In the example of [Fig.1], the turbomachine 2 is a turbofan engine comprising, from upstream to downstream, a fan 4, a low-pressure compressor 5, a high-pressure compressor 6, a combustion chamber 7, a high-pressure turbine 8 and a low-pressure turbine 9. The compressors 5 and 6, the combustion chamber 7 and the turbines 8 and 9 form a gas generator.

[0053] During the operation of the turbojet 2, an airflow 10 enters the propulsion assembly 1 through an air inlet in the nacelle 3, passes through the fan 4 and then It is divided into a central primary flow 10A and a secondary flow 10B. The primary flow 10A flows in a primary gas circulation duct 1IA within the gas generator. The secondary flow 10B flows in a secondary duct 1IB surrounding the gas generator and radially bounded outwards by the nacelle 3.

[0054] In a manner known per se, the turbines 8 and 9 each comprise at least one distributor and at least one moving wheel each having blades, visible on [Fig.1], which extend into the primary conduit 11A.

[0055] Figure 2 shows a vane 20 for a rotating wheel equipping in this example the high-pressure turbine 8.

[0056] The blade 20 has a conventional general structure, including a blade 21, a foot 22 intended to cooperate with a housing for a disc (not shown) of the moving wheel and a platform 23 intended to radially delimit inwards the primary conduit 11 A.

[0057] In service, the blade 21 extends into the primary conduit 1 IA and is consequently exposed to hot gases from the combustion chamber 7 (see [Fig.1]).

[0058] The turbojet 2 includes a cooling circuit for supplying fresh air into an internal cavity 25 of the blade 20.

[0059] The blade 20 includes cooling ports 26 connecting an internal surface (not visible in [Fig.2]) of the blade 21 to an external surface 27 of the blade 21, the internal surface delimiting the internal cavity 25, the external surface 27 being exposed to the primary flow 10A.

[0060] The cooling orifices 26 allow some of the fresh air circulating in the internal cavity 25 of the blade 20 to be evacuated so as to form on the external surface 27 a film of fresh air protecting the blade 21 from the hot combustion gases 10A.

[0061] The invention relates to the geometry of such cooling orifices 26.

[0062] Figure 3 shows a portion of a wall 30 comprising a re-orifice cooling 26 according to the invention.

[0063] The cooling orifice 26 has a flow axis A2.

[0064] The wall 30 comprises a first surface 31 delimiting a first space 25 and a second surface 27, opposite with respect to the first surface 31, delimiting a second space 11 A.

[0065] The distance between the first surface 31 and the second surface 27 defines a wall thickness 30.

[0066] The cooling orifice 26 is configured to convey a cooling fluid circulating in the first space 25 to the second space 11A through the wall 30, i.e. from the first surface 31 to the second surface 27, so as to form a film of cooling fluid on the second surface 27.

[0067] In this example, the wall 30 of [Fig.3] forms the blade 21 of the blade 20 of [Fig.2], so that said first surface 31 forms the internal surface of the blade 21, said second surface forms the external surface 27 of the blade 21, said first space corresponds to the internal cavity 25 of the blade 20 and said second space corresponds to the primary duct 11A of the turbojet 2.

[0068] By way of non-limitation, in undetailed embodiments, the wall 30 of [Fig.3] can form a moving wheel blade and / or distributor of the high-pressure turbine 8 and / or the low-pressure turbine 9 and / or a wall of the combustion chamber 7. The present description applies by analogy to these embodiments.

[0069] Of course, the wall 30 can include several cooling ports 26 as described below with reference to Figures 3 and following.

[0070] With reference to [Fig.3], the cooling orifice 26 includes a dosing portion 32, or calibrating portion, which opens onto the first surface 31 so as to form an inlet 35 of the cooling orifice 26 and a diffusion portion 33 which opens onto the second surface 27 so as to form an outlet 36 of the cooling orifice 26.

[0071] In this example, the dosing portion 32 has a cylindrical section of diameter XI and has a central axis forming said flow axis A2.

[0072] The flow axis is oblique with respect to the first surface 31 and the second surface 27.

[0073] The dosing portion 32 allows the quantity of cooling air entering the cooling orifice 26 through the inlet 35, from the first space 25, to be dosed or calibrated.

[0074] The diffusion portion 33 extends the dosing portion 32 so that the airflow entering the cooling orifice 26 through the inlet 35 can exit through the outlet 36.

[0075] With reference to a flow direction S2 of the cooling airflow passing through the cooling orifice 26, the downstream end 37 of the dosing portion 32, i.e. the outlet of the dosing portion 32, constitutes the upstream end of the diffusion portion 33, i.e. the inlet of the diffusion portion 33.

[0076] The diffusion portion 33 is flared so that the outlet section 36 has an area greater than the area of ​​the upstream end 37 of the diffusion portion 33 and consequently greater than the area of ​​the inlet section 35.

[0077] The diffusion portion 33 is formed by removing material from the wall 30 so that the latter forms a third surface which delimits the diffusion portion 33.

[0078] In the embodiment of figures 3 to 6, the third surface comprises a central edge 40 and two lateral edges 41 and 42.

[0079] In this example, edges 40, 41 and 42 are straight, that is to say rectilinear over their entire extent.

[0080] The central edge 40 extends along the flow axis A2 and is inclined, oblique, with respect to the flow axis A2 (see [Fig.3]).

[0081] More specifically, the central edge 40 is oriented with respect to the flow axis A2 so as to move away from it in the direction of flow S2.

[0082] The lateral edges 41 and 42 also extend along the flow axis A2, each being oblique to the flow axis A2 so as to move away from it in the direction of flow S2 (see [Fig.3]).

[0083] The third surface is in this example segmented into three surface parts 44, 45 and 46 (see [Fig.4]).

[0084] The surface part 44 is delimited by the central edge 40 and by the lateral edge 41, the surface part 45 is delimited by the central edge 40 and by the lateral edge 42, while the surface part 46 is delimited by the lateral edges 41 and 42.

[0085] The surface parts 44 and 45 form a flared surface of the diffusion portion 33.

[0086] In this embodiment, the surface parts 44 and 45 are flat and the surface part 46 is curved.

[0087] In this example, the surface parts 44 to 46 are smooth, that is to say, devoid of discontinuity.

[0088] With reference to figures 3 and 4, the outlet section 36 of the cooling orifice 26 is formed by two straight edges 47 and 48 and by a curved line 49.

[0089] Edges 47 and 48 are formed by an edge of surface parts 44 and 45, respectively, while line 49 is formed by an edge of surface part 46.

[0090] The edges 47 and 48 as well as the exit section line 49 thus delimit the third surface and the second surface 27 to each other.

[0091] Thus, in this embodiment, the surface part 44 is delimited by the central edge 40, the lateral edge 41, the exit section edge 47 and by a first segment of the inlet 37 of the diffusion portion 33. The surface part 45 is delimited by the central edge 40, the lateral edge 42, the exit section edge 48 and by a second segment of the inlet 37 of the diffusion portion 33. Finally, the surface part 46 is delimited by the lateral edges 41 and 42, by the exit section line 49 and by a third segment of the inlet 37 of the diffusion portion 33.

[0092] In this example, the diffusion portion 33 has a transverse plane of symmetry passing through the central edge 40 and through the flow axis A2.

[0093] In other words, the diffusion portion 33 comprises two symmetrical half-parts with respect to a transverse plane passing through the central edge 40.

[0094] With reference to Figures 3 and 5, the central edge 40 has a length greater than that of each of the lateral edges 41 and 42 and greater than that of any line parallel to the central edge 40 formed by the third surface.

[0095] The central edge 40 thus forms a bottom of the diffusion portion 33 so that, in any section formed by a plane normal to the flow axis A2 and intersecting the central edge 40, the point of the central edge 40 passing through this plane is the point furthest from the flow axis A2 among all the points of the third surface contained in this section.

[0096] In the example of [Fig.3], the third surface forms, opposite the central edge 40 with respect to the flow axis A2, a ridge line which extends from the inlet 37 of the diffusion portion 33 to the outlet 36 of the cooling orifice parallel to the flow axis A2.

[0097] This ridge line extends more precisely to a distance from the flow axis A2 which corresponds to half of the diameter XI of the dosing portion 32.

[0098] In this example, in any section formed by a plane normal to the flow axis A2 and intersecting the ridge line, the point on this ridge line passing through this plane is the point closest to the flow axis A2 among all the points of the third surface contained in this section.

[0099] The cooling orifice 26 of the invention makes it possible to reduce the formation of counter-rotating vortices in the bottom of the diffusion portion 33, in particular on a downstream section of the diffusion portion 33, and thus makes it possible to channel a fraction of the cooling fluid outside of an area of ​​influence of such vortices.

[0100] The channeling function is ensured in particular by the surface parts 44 and 45 which thus form guiding portions.

[0101] In the embodiment shown in Figures 3 to 6, the central edge 40 and the lateral edges 41 and 42 do not meet or intersect. With reference to Figures 3 and 6, the edges 40-42 form distinct points in the inlet section 37 of the diffusion portion 33, each having a circumferential coordinate around the flow axis A2.

[0102] The embodiment of [Fig.7] differs from that of Figures 3 to 6 in that the lateral edges 41 and 42 intersect the central edge 40 in the inlet section 37 of the diffusion portion 33.

[0103] In the embodiments described above, the guide portions 44 and 45 are planar.

[0104] Alternatively, the guide portions 44 and 45 can be curved, for example so as to form concave ([Fig.8]) or convex ([Fig.9]) surface parts.

[0105] In all these examples, the diffusion portion 33 is devoid of a lobe.

[0106] The inventors estimated that a cooling orifice 26 comprising a diffusion portion 33 as illustrated in [Fig.4] provides a cooling efficiency gain of nearly twenty percent compared to a conventional diffusion portion, at equivalent blowing rates.

[0107] Of course, the edges 40, 41 and 42 may have a radius of curvature, so as to form a rounded or fillet shape, taking into account manufacturing constraints in particular. Figure 10 illustrates a diffusion portion 33 with a rounded central edge 40.

Claims

Claims

1. Component (20) for a turbomachine (2), comprising a wall (30) having a first surface (31) and a second surface (27) opposite the first surface (31), the wall (30) comprising at least one cooling orifice (26) which has a flow axis (A2) and which is configured to convey a cooling fluid from the first (31) to the second surface (27) through the wall (30), the cooling orifice (26) comprising a metering portion (32) which opens onto the first surface (31) and a diffusion portion (33) devoid of lobes and which opens onto the second surface (27), the diffusion portion (33) being delimited by a flared surface (44, 45), characterized in that the flared surface (44, 45) comprises a central edge (40) forming a bottom of the diffusion portion (33), in that the flared surface (34) comprises two lateral edges (41,42) which laterally delimit on either side the flared surface (44, 45) and each define with the central edge (40) a flow guide portion (44, 45), the central edge (40) and the lateral edges (41, 42) being rectilinear over their entire extent going from an inlet section (37) of the diffusion portion (33) to an outlet (36) of the cooling orifice (26).,

2. Component (20) according to claim 1, wherein the guide portions (44, 45) are planar.

3. Component (20) according to claim 1 or 2, wherein the side edges (41, 42) are inclined relative to the central edge (40).

4. A component (20) according to any one of claims 1 to 3, wherein the central edge (40) has a length greater than that of each of the side edges (41, 42).

5. A component (20) according to any one of claims 1 to 4, wherein the side edges (41, 42) intersect the central edge (40) in the inlet section (37) of the diffusion portion (33).

6. A component (20) according to any one of claims 1 to 5, wherein the flared surface (44, 45) is symmetrical about a plane passing through the central edge (40).

7. Turbine (8, 9) for turbomachine (2), comprising a moving wheel, a distributor and at least one component (20) according to any one of claims 1 to 6 forming a blade (20) of the moving wheel or of the dis- tributor.

8. Combustion chamber (7) for a turbomachine (2), comprising at least one component according to any one of claims 1 to 6 forming a wall (30) of the combustion chamber.

9. Turbomachine (2) for an aircraft such as an airplane or a helicopter, comprising a turbine (8, 9) according to claim 7 and / or a combustion chamber (7) according to claim 8.

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