Rotor blade for an aircraft turbine engine

Abstract

The invention relates to a rotor blade (20) for an aircraft turbine engine, this blade (20) comprising a blade airfoil (22) and a root (24) connected to the blade airfoil (22) by a platform (26), the blade airfoil (22) extending from the platform (26) to a free end (22a) comprising a recessed pocket (36), the blade airfoil (22) having a leading edge (28) and a trailing edge (30), and pressure-side and suction-side faces (32, 34) which extend from the leading edge (28) to the trailing edge (30), the blade (20) also having an internal circuit (38) for the passage of ventilation air, the internal circuit (38) extending from the root (24) to the free end (22a), the internal circuit (38) comprising an internal cavity (50) which is located at the free end (22a), just below the pocket (36), and which is connected to the bottom (44) of the pocket (36) by outlet openings (42), this cavity (50) having an elongate shape from the leading edge (28) to the trailing edge (30) and being surrounded by parts of the pressure-side and suction-side faces (32, 34).

Description

[0001] DESCRIPTION

[0002] TITLE: ROTOR BLADE FOR AN AIRCRAFT TURBOMACHINE

[0003] Technical field of the invention

[0004] The present invention relates in particular to a rotor blade for an aircraft turbomachine.

[0005] Technical background

[0006] An aircraft turbomachine typically comprises at least one compressor, one annular combustion chamber, and at least one turbine. Air entering the compressor is compressed, then mixed with fuel and burned in the combustion chamber. The combustion gases are then expanded in the turbine, which drives the turbine rotor, which in turn drives the compressor rotor.

[0007] There are several turbomachine technologies, such as turboprops or turbojets, which include, for example, a propulsion propeller located upstream of the turbomachine and which is also driven by the turbine rotor, this propeller being able to be shrouded or unshrouded.

[0008] There are also several turbomachine configurations, such as single-spool or multi-spool. In a twin-spool turbomachine, for example, the turbomachine comprises a low-pressure (LP) spool and a high-pressure (HP) spool. The low-pressure spool includes a low-pressure compressor rotor connected by a low-pressure shaft to a low-pressure turbine rotor. The high-pressure spool includes a high-pressure compressor rotor connected by a high-pressure shaft to a high-pressure turbine rotor. In the direction of gas flow within the turbomachine, from upstream to downstream, the twin-spool turbomachine thus comprises the low-pressure compressor, the high-pressure compressor, the combustion chamber, the high-pressure turbine, and the low-pressure turbine.

[0009] A turbomachine compressor comprises one or more compression stages extending around and along a single axis, each of which includes a rotor wheel and a stator blade (also called a rectifier blade).

[0010] Similarly, a turbomachine turbine comprises one or more expansion stages which extend around and along the same axis, and which each include a rotor wheel and a stator blade (also called a distributor blade).

[0011] Figure 1 shows part of a turbomachine turbine 10 and in particular a rotor wheel 12 axially interposed between two stator blades 14, 16.

[0012] The rotor wheel 10 generally comprises a disc 18 carrying blades 20 at its periphery. The disc 18 is centered on the axis of rotation of the wheel 12 and the blades 20 are distributed around this axis and mounted at the periphery of the disc 18.

[0013] The rotor blade 20 here comprises a blade 22 and a foot 24 connected to the blade 22 by a platform 26. The blade 22 extends from the platform 26 to a free end 22a (also called the apex) opposite the platform 26, along an axis of extension A.

[0014] The blades 20 are mounted side by side on the disc 18 by fitting their feet 24 into recesses on the outer periphery of the disc 18.

[0015] The blade 22 has a leading edge 28 and a trailing edge 30, as well as intrados 32 and extrados 34 faces which extend from the leading edge 28 to the trailing edge 30 (figures 1 and 2).

[0016] The free end 22a comprises a recessed tub 36 which is elongated from the leading edge 28 to the trailing edge 30 and is surrounded by portions of the intrados 32 and extrados 34 faces, as shown in Figure 2. The blade 20 further comprises an internal ventilation air passage circuit 38 extending from the foot 24 to the free end 22a, and which includes air inlet ports 40 formed in the foot 24 (Figure 1), and air outlet ports 42 formed at the bottom 44 of the tub 36 (Figure 2). The internal circuit 38 further comprises internal pockets 46 which are connected to the tub by the air outlet ports 42. The trailing edge 30 further includes air outlet openings 48 which open into the internal pocket 46 located closest to the trailing edge 30 (figure 2).

[0017] Bath turbine blades are generally those of high-pressure turbines and are therefore located just outside the combustion chamber. These blades can be regularly exposed to temperatures exceeding the melting point of the metal from which they are made. To counteract this effect, the blades' internal cooling circuits allow them to be cooled by circulating ventilation air from their roots to their baths. These blades are cooled from the inside by air circulating within internal pockets. In addition, a ceramic coating can be applied to the blade to further protect the metal from the temperature.

[0018] The technical problem to be solved is increasing the temperature resistance of this type of blade, and in particular its tip containing the tub. Indeed, despite the blade's cooling, this free end is subjected to the highest temperature.

[0019] This temperature can generate defects (corrosion, oxidation, burning, cracks, etc.) and accelerate the aging of the blade.

[0020] The invention offers a solution to this problem that is simple, effective, and economical.

[0021] Summary of the invention

[0022] The invention relates to a rotor blade for an aircraft turbomachine, this blade comprising a blade and a root connected to the blade by a platform, the blade extending from the platform to a free end opposite the platform, along an axis of elongation, the blade comprising a leading edge and a trailing edge, as well as intrados and extrados faces extending from the leading edge to the trailing edge, said free end comprising a recessed basin having an elongated shape from the leading edge to the trailing edge and surrounded by portions of said intrados and extrados faces, the blade further comprising an internal ventilation air passage circuit extending from the root to said free end, and comprising at least one air inlet orifice formed in the root, and at least one air outlet orifice formed at the bottom of said basin.characterized in that said internal circuit comprises an internal cavity which is located at said free end, just below said tub, and which is connected to the bottom of the tub by said at least one outlet orifice, this cavity having an elongated shape from the leading edge to the trailing edge and being surrounded by portions of said intrados and extrados faces.

[0023] The invention therefore proposes an improved internal circuit for a tub rotor blade, this internal circuit comprising an internal cavity directly beneath the tub and extending along its length. The addition of this cavity allows for better cooling of the blade tip and thus reduces the risk of blade damage.

[0024] The blade according to the invention may comprise one or more of the following features, taken individually or in combination with each other:

[0025] - said cavity has a general shape similar to that of the bathtub, the bathtub and the cavity following an aerodynamic profile of the blade;

[0026] - the cavity and the tub each have a shape in the form of a portion of a blade and each comprise two curved walls, respectively concave and convex, which are similar to the intrados and extrados faces of the portion of the blade, and two opposite connecting edges of these curved walls, which are similar to the leading and trailing edges of the portion of the blade;-- the cavity has a length measured in a direction passing through the leading and trailing edges of the blade, which is equal to approximately + / -10% to a length of the tub measured in the same direction;

[0027] -- the cavity has a maximum width measured in a direction normal to at least one of the intrados and extrados faces, which is equal to approximately + / -10% to a maximum width of the tub measured in the same direction;

[0028] -- the cavity has a height measured in a direction parallel to the elongation axis, which is equal to approximately + / -10% to a height of the bathtub measured in the same direction;

[0029] - the cavity is separated from the bathtub by a distance measured along the axis of elongation which is less than a height of the cavity and / or a height of the bathtub measured in the same direction;

[0030] - the cavity is connected to the bathtub by at least two or three outlet orifices which extend parallel to said axis of elongation;

[0031] - the internal circuit includes internal pockets which are separated from said tub by said internal cavity and are connected to the internal cavity by at least one, and preferably at least two or three, air passage orifice(s);

[0032] - at least some of the internal pockets have an elongated shape along the axis of elongation and include longitudinal ends located on the side of the internal cavity and connected to the internal cavity by said at least one passage orifice;

[0033] - at least three, or even four, internal pockets are connected to the internal cavity;

[0034] - at least part of said internal pockets includes smooth internal surfaces; the presence of smooth surfaces characterized by the absence of disturbances and / or perforations, minimizes heat exchange with the rest of the blade and thus allows the maximum amount of cold air to be brought into the cavity;

[0035] - the internal cavity comprises transverse partitions; - each of the partitions is connected to a wall of the cavity located on the intrados or extrados side;

[0036] -- each of the partitions has a dimension measured in a direction normal to the intrados or extrados face, which represents more than 50% of a maximum dimension of the cavity measured in the same way at the level of the corresponding partition;

[0037] - the pockets are separated from each other by veils of material extending along the axis of elongation, and in which the partitions extend in the continuation of these veils of material;

[0038] - the blade includes drillings extending from said cavity to the intrados face and / or the extrados face.

[0039] The present invention also relates to a turbine for an aircraft turbomachine, comprising several blades as described above which are mounted side by side on a rotor disc, by fitting their feet into recesses in the outer periphery of the disc.

[0040] Brief description of the figures

[0041] Other features and advantages will become apparent from the following description of a non-limiting embodiment of the invention with reference to the accompanying drawings in which:

[0042] [Fig.1] Figure 1 is a semi-schematic axial cross-sectional view of an aircraft turbomachine turbine,

[0043] [Fig.2] Figure 2 is a partial schematic perspective view of a rotor blade apex,

[0044] [Fig. 3] Figure 3 is a partial schematic perspective view of a rotor blade apex according to one embodiment of the invention, [Fig. 4] Figure 4 is a partial schematic perspective view of a rotor blade apex according to an alternative embodiment of the invention, [Fig. 5] Figure 5 is a schematic cross-sectional view of the blade of Figure 4, the section passing through the internal cavity of the apex of this blade, and

[0045] [Fig.6] Figure 6 is a partial schematic perspective view of a rotor blade apex according to another embodiment of the invention.

[0046] Detailed description of the invention

[0047] Figures 1 and 2 have already been described above.

[0048] Figure 3 illustrates a first embodiment of a rotor blade 20 according to the invention for a turbine 10 and an aircraft turbomachine, such as that illustrated in Figure 1.

[0049] The blade 20 is similar to that of Figures 1 and 2 and comprises a blade 22 and a foot 24 (not visible in Figure 3) connected to the blade 22 by a platform 26 (not visible). The blade 22 extends from the platform 26 to a free end 22a (or apex) opposite the platform 26, along an axis of extension A.

[0050] The blade 22 has a leading edge 28 and a trailing edge 30, as well as intrados 32 and extrados 34 faces which extend from the leading edge 28 to the trailing edge 30.

[0051] The free end 22a has a hollow tub 36 which has an elongated shape from the leading edge 28 to the trailing edge 30 and which is surrounded by parts of the intrados 32 and extrados 34 faces, as seen in figure 3.

[0052] The vane 20 further includes an internal ventilation air passage circuit 38 which extends from the foot 24 to the free end 22a, and which includes at least one air inlet orifice 40 (not visible) formed in the foot 24, and at least one air outlet orifice 42 formed at the bottom 44 of said tub 36 (figure 2).

[0053] The internal circuit 38 further includes internal pockets 46 which are connected to the tub 36 by the air outlet(s) 42. The trailing edge 30 may further include air outlet openings 48 which open into the internal pocket 46 located closest to the trailing edge 30 (Figure 3).

[0054] At least part of the internal pockets 46 includes smooth internal surfaces and therefore does not include disruptors or perforations.

[0055] The particularity of the blade 20 according to the invention, which distinguishes it from that of figures 1 and 2, is related to the fact that the internal circuit 38 includes an internal cavity 50 which is located at the free end 20a, just below the tub 36. This cavity 50 is connected to the bottom 44 of the tub 36 by the outlet orifice(s) 42. This cavity 50 has an elongated shape from the leading edge 28 to the trailing edge 30 and is surrounded by parts of the intrados and extrados faces 32, 34, as can be seen in figure 3.

[0056] Advantageously, the cavity 50 has a general shape similar to that of the tub 36. The tub 36 and the cavity 50 thus preferably follow an aerodynamic profile of the blade 22.

[0057] The cavity 50 and the tub 36 preferably each have a shape in the form of a portion of a blade and each comprise two curved walls, respectively concave P1 and convex P2, which are similar to the intrados and extrados faces of the portion of a blade, and two opposite edges B1, B2 of connection of these curved walls P1, P2, which are similar to the leading and trailing edges of the portion of a blade.

[0058] The cavity 50 preferably has a length L1 measured in a direction passing through the leading and trailing edges 28, 30 of the blade 22, which is equal to approximately + / -10% to a length L2 of the tub 36 measured in the same direction.

[0059] The cavity 50 has a maximum width U1 measured in a direction normal to at least one of the intrados and extrados faces 32, 34, which is equal to approximately + / -10% to a maximum width U2 of the tub 36 measured in the same direction. The cavity preferably has a height H1 measured in a direction parallel to the elongation axis A, which is equal to approximately + / -10% to a height H2 of the tub measured in the same direction.

[0060] Advantageously, the cavity 50 is separated from the tub 36 by a distance X measured along the elongation axis A which is less than the height H1 of the cavity 50 and / or the height H2 of the tub 36 measured in the same direction.

[0061] Advantageously, the cavity 50 is connected to the tub 36 by at least two or three outlet ports 42 which extend parallel to the elongation axis 46.

[0062] The internal pockets 46 are separated from the tub 36 by the internal cavity 50 and are connected to this internal cavity 50 by at least one, and preferably at least two or three, air passage(s) 52. The number of these air passages 52 can be equal to the number of internal pockets 46 in the circuit 38, and each of these pockets 46 can be connected to the cavity 50 by one of the air passages 42. The number of air passages 52 can be equal to the number of air passages 42. Each of the air passages 52 can be aligned with one of the air passages 42, as in the example shown.

[0063] The internal cavity 50 may include a bottom 50a located on the side of the blade foot, and a top 50b located on the side of the tub 36. Preferably, the bottom 50a and the top 50b are parallel. Preferably, the orifices 42 open respectively into the bottom 44 of the tub 36 and the top 50b of the cavity 50. Preferably, the orifices 52 open respectively into the bottom 50a of the cavity 50 and into the pockets 46.

[0064] At least some of the internal pockets 46 preferably have an elongated shape along the elongation axis A. At least some of the internal pockets 46 may include longitudinal ends 46a located on the side of the internal cavity 50, which are connected to the internal cavity 50 by the passage orifices 52. At least three, or even four, internal pockets 46 may be connected to the internal cavity 50.

[0065] The variant embodiment of figures 4 and 5 differs from the blade 20 of figure 3 essentially in that the internal cavity 50 includes transverse partitions 54.

[0066] Preferably, each of the partitions 54 is connected to a wall 50c, 50d of the cavity 50 located on the side of the intrados or extrados face 32, 34.

[0067] Each of the partitions 54 preferably has a dimension R1 measured in a direction normal to the intrados or extrados face 32, 34, which represents more than 50% of a maximum dimension R2 of the cavity 50 measured in the same way at the level of the corresponding partition 54.

[0068] The pockets 46 are preferably separated from each other by sails of material 56 which extend along the axis of elongation A. The partitions 54 preferably extend in the continuation of these sails of material 56.

[0069] The variant embodiment of figure 6 differs from the blade 20 of figure 3 essentially in that the blade 22 further includes holes 58 extending from the cavity 50 to the intrados face 32 and / or the extrados face 34. These holes 58 can be inclined with respect to normals to the faces 32, 34, in particular so that their ends which open onto these faces 32, 34 are oriented on the side opposite to the foot of the blade.

Claims

DEMANDS 1. Rotor blade (20) for an aircraft turbomachine, said blade (20) comprising a blade (22) and a root (24) connected to the blade (22) by a platform (26), the blade (22) extending from the platform (26) to a free end (22a) opposite the platform (26), along an axis of extension (A), the blade (22) comprising a leading edge (28) and a trailing edge (30), as well as upper and lower surfaces (32, 34) extending from the leading edge (28) to the trailing edge (30), said free end (22a) comprising a recessed tub (36) having an elongated shape from the leading edge (28) to the trailing edge (30) and surrounded by portions of said upper and lower surfaces (32, 34), the blade (20) further comprising an internal ventilation air passage circuit (38) extending from the foot (24) to said free end (22a), and comprising at least one air inlet orifice (40) formed in the foot (24),and at least one air outlet orifice (42) formed at the bottom (44) of said tub (36), characterized in that said internal circuit (38) comprises an internal cavity (50) which is located at said free end (22a), just below said tub (36), and which is connected to the bottom (44) of the tub (36) by said at least one outlet orifice (42), this cavity (50) having an elongated shape from the leading edge (28) to the trailing edge (30) and being surrounded by portions of said intrados and extrados faces (32, 34).

2. Blade (20) according to claim 1, wherein said cavity (50) has a general shape similar to that of the tub (36), the tub (36) and the cavity (50) following an aerodynamic profile of the blade (22).

3. Blade (20) according to claim 1 or 2, wherein the cavity (50) and the tub (36) each have a blade portion shape and each comprise two curved walls, respectively concave and convex (P1, P2), which are similar to the intrados and extrados faces of the blade portion, and two opposite connecting edges (B1, B2) of these curved walls (P1, P2), which are similar to the leading and trailing edges of the blade portion.

4. Blade (20) according to any one of the preceding claims, wherein the cavity (50) is separated from the tub (36) by a distance (X) measured along the elongation axis (A) which is less than a height (H1) of the cavity (50) and / or a height (H2) of the tub (36) measured in the same direction.

5. Blade (20) according to any one of the preceding claims, wherein the cavity (50) is connected to the tub (36) by at least two or three outlet orifices (42) extending parallel to said elongation axis (A).

6. Blade (20) according to any one of the preceding claims, wherein the internal circuit (38) comprises internal pockets (46) which are separated from said tub (36) by said internal cavity (50) and are connected to the internal cavity (50) by at least one, and preferably at least two or three, air passage orifice(s) (52).

7. Blade (20) according to claim 6, wherein at least some of the internal pockets (46) have an elongated shape along the elongation axis (A) and include longitudinal ends (46a) located on the side of the internal cavity (50) and connected to the internal cavity (50) by said at least one passage orifice (52).

8. Blade (20) according to claim 6 or 7, in which at least three, or even four, internal pockets (46) are connected to the internal cavity (50).

9. Blade (20) according to any one of claims 6 to 8, wherein at least a part of said internal pockets (46) comprises smooth internal surfaces.

10. Blade (20) according to any one of the preceding claims, wherein the internal cavity (50) comprises transverse partitions (54).

11. Blade (20) according to claim 10, in which each of the partitions (54) is connected to a wall (50a, 50b) of the cavity (50) located on the side of the intrados or extrados face (32, 34).

12. Blade (20) according to claim 10 or 11, depending on any one of claims 6 to 9, wherein the pockets (46) are separated from each other by sails of material (56) extending along the axis of elongation (A), and wherein the partitions (54) extend in the continuation of these sails of material (56).

13. Blade (20) according to any one of the preceding claims, wherein the blade (22) comprises drillings (58) extending from said cavity (50) to the intrados face (32) and / or the extrados face (34).

14. Turbine (10) for an aircraft turbomachine, comprising several blades (20) according to any one of the preceding claims which are mounted side by side on a rotor disk (18), by fitting their feet (24) into recesses in the outer periphery of the disk (18).

Images