Rotor blade for an aircraft turbine engine

Abstract

The invention relates to a rotor blade (20) for an aircraft turbine engine, this blade comprising an airfoil (22) and a root connected to the airfoil by a platform, the airfoil extending from the platform to a free end (22a) comprising a recessed bathtub (36), the rotor blade further comprising an internal circuit (38) for ventilation air to pass therethrough, the internal circuit (38) extending from the root to the free end and opening out through at least one air outlet opening (42) formed in the bottom (44) of the bathtub, the at least one air outlet opening extending along an axis (X) that is not parallel to a longitudinal axis (A) of the airfoil, the at least one opening being oriented toward a wall (33) of a pressure-side face (32) of the airfoil and toward the trailing edge (30) of the airfoil when the opening opens out at the bottom of the bathtub.

Description

Description TITLE: ROTOR BLADE FOR AN AIRCRAFT TURBOMACHINE Technical field of the invention

[0001] The present invention relates to a rotor blade for an aircraft turbomachine. Technological background

[0002] 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.

[0003] 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.

[0004] 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.

[0005] 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).

[0006] 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).

[0007] Figure 1 shows part of a turbomachine turbine 10 and in particular a rotor wheel 12 axially interposed between two stator blades 14, 16.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] 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).

[0012] 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, on one side, by a wall 33 of the intrados face 32 and, on the other side, by a wall 35 of the extrados face 34, as can be seen in figures 2 and 3.

[0013] The blade 20 also includes an internal ventilation air passage 38 extending from the foot 24 to the free end 22a, comprising 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 (Figures 2 and 3). The air outlet ports 42 are also oriented radially, i.e., parallel to the elongation axis A, to ensure the evacuation of ventilation air (Figure 2).

[0014] The internal circuit 38 further includes internal pockets 46 which are connected to the tub by 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).

[0015] 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.

[0016] Documents JP-B2-6885677, CN-A-1920258, US-A1-2022 / 290568, USAI-2016 / 169002 or US-B2-10563519 show examples of rotor blades for aircraft turbomachinery.

[0017] 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, which can reach 1200°C.

[0018] This temperature can generate defects (corrosion, oxidation, burning, cracks, etc.) and accelerate the aging of the blade.

[0019] The invention offers a solution to this problem that is simple, effective, and economical. Summary of the invention

[0020] A rotor blade for an aircraft turbomachine is therefore proposed, 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 aspect, the blade having a leading edge and a trailing edge, as well as intrados and extrados faces extending from the leading edge to the trailing edge, the free end having a recessed basin which has an elongated shape from the leading edge to the trailing edge and which is surrounded by walls of the intrados and extrados faces, the blade further comprising an internal ventilation air passage circuit which extends from the root to the free end, and which includes at least one air inlet orifice formed in the root, and at least one air outlet orifice formed at the bottom of the basin, the air outlet orifice extending along an axis not parallel to the axis of elongation,this opening being oriented towards the wall of the intrados face and the trailing edge when it opens at the bottom of said bathtub.

[0021] Thus, thanks to the invention, improved cooling of the free end of the blade is ensured. Indeed, since the air outlet(s) are oriented towards the wall of the lower surface and the trailing edge, i.e., in a non-radial manner, the escaping airflow is advantageously directed towards those parts of the blade most affected by the temperature effects of the hot airflow from the duct. In other words, the airflow generated by the internal ventilation air passage of the blade, and exiting through the air outlet(s), is directed towards a hot area of ​​the water bath to improve local heat exchange, thereby enhancing cooling and reducing blade degradation and slowing its aging.

[0022] The blade according to the invention may comprise one or more of the following features, taken individually or in combination with each other: at least one orifice has a general cylindrical shape; - the axis not parallel to the axis of elongation is inclined relative to the bottom of the bathtub with an angle of inclination between 15 degrees and 80 degrees; - the bottom of the bathtub has, at the level of the opening of each air outlet in the bathtub, a recess which flares out from the opening of the orifice towards the wall of the intrados face and the trailing edge; - the recess includes a projection face which is oriented towards the wall of the intrados face and the trailing edge; the recess has a general inverted pyramid shape, the apex of which is roughly centered on the air outlet; - the inverted pyramid has a triangular or polygonal base; - the projection face is inclined relative to the bottom of the bathtub with an angle between 5 degrees and 60 degrees; - at least one air outlet is located equidistant from the walls of the intrados and extrados faces surrounding the tub and is located at a distance from a longitudinal end of the tub, located on the trailing edge side; - the projection face has a triangular shape whose apex located at the level of the air outlet forms an angle between 10 degrees and 60 degrees; - the blade includes at least two air outlets; - the awl includes at least one dust removal opening at the bottom of the tub; - at least one dust extraction orifice has a cross-section whose dimension is greater than the dimension of a cross-section of the air outlet orifice.

[0023] The 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. Brief description of the figures

[0024] The invention will be better understood with the aid of the following description, given solely by way of example and made with reference to the accompanying drawings in which:

[0025] Figure 1 shows a semi-schematic axial cross-sectional view of an aircraft turbomachine turbine,

[0026] Figure 2 shows a partial schematic perspective view of a rotor blade apex,

[0027] Figure 3 shows a partial schematic top view of the top of the blade in Figure 2.

[0028] Figure 4 shows a partial schematic perspective view of a vertex of a rotor blade according to the invention,

[0029] Figure 5 shows a partial schematic top view of a vertex of a rotor blade according to the invention,

[0030] Figure 6 shows a partial schematic top view of the blade tip of Figure 5, specifically visualizing an area of ​​airflow distribution through an air outlet orifice.

[0031] Figure 7 shows a schematic axial cross-sectional view of the apex of the blade in Figure 5. Detailed description of the invention

[0032] Figures 1 to 3 have been described above.

[0033] We now turn our attention to Figure 4, which shows an example of an embodiment of the rotor blade 20 according to the invention for a turbine 10 and an aircraft turbomachine, as illustrated in Figure 1. In particular, Figure 4 illustrates the tip of the blade 22 of the blade 20.

[0034] The blade 20 is similar to that shown in Figures 1 to 3 and comprises a blade 22 and a foot 24, not shown in Figure 4, 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.

[0035] The blade 22 has a leading edge 28 and a trailing edge 30, as well as an intrados face 32 and an extrados face 34 which extend from the leading edge 28 to the trailing edge 30.

[0036] 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 on one side by a wall 33 of the intrados face 32 and, on the other side, by a wall 35 of the extrados face 34.

[0037] 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 air inlet orifices 40 (not visible in figure 4) formed in the foot 24, and air outlet orifices 42 formed at the bottom 44 of the tub 36.

[0038] The internal circuit 38 further includes internal pockets 46 which are connected to the tub by 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.

[0039] The distinctive feature of the blade 20 according to the invention, which sets it apart from those of Figures 1 to 3, lies in the fact that the air outlet orifice(s) 42 extend along an axis X that is not parallel to the axis of extension A. In other words, the orifice(s) 42 are inclined and are not oriented radially with respect to the rotor wheel on which the blade according to the invention is intended to be mounted. Furthermore, the air outlet orifice(s) 42 are oriented towards the wall 33 of the intrados face and the trailing edge 30 when the orifice(s) 42 open into the bottom 44 of the tub 36.

[0040] The non-radial orientation, on the one hand, and towards the intrados face 32 and the trailing edge 30, on the other hand, of the orifice(s) 42 allows the airflow coming out of it to be directed more effectively towards the parts of the blade 20 most affected by the high temperature of the airflow from the vein.

[0041] Advantageously, the X-axis, not parallel to the elongation axis A of each air outlet 42, is inclined relative to the bottom 44 of the tub 36 with an angle of inclination between 15 degrees and 80 degrees. In the example shown in Figure 4, the angle formed by the air outlet 42 is approximately 60 degrees.

[0042] Each air outlet 42 can have a general cylindrical shape.

[0043] Each air outlet 42 can be located equidistant from the walls 33, 35 of the intrados 32 and extrados 34 faces surrounding the tub 36. In addition, each outlet 42 can be located at a distance from a longitudinal end 37 of the tub 36, this longitudinal end 37 being located on the trailing edge side 30.

[0044] It is understood that the air outlet(s) 42 are located away from the longitudinal end 37. This improves the diffusion of the ventilation airflow exiting the outlet(s) 42. Preferably, the air outlet(s) 42 are situated at a distance from the hot zone to be cooled.

[0045] We now refer to figures 5 to 7 which represent another embodiment of the blade 20 according to the invention.

[0046] In this embodiment, the dawn 20 is similar to what was described previously in relation to figure 4.

[0047] In this embodiment, the bottom 44 of the bathtub 36 advantageously includes, at the level of the outlet of each air outlet 42 in the bathtub 36, a recess 50 which flares out from the outlet of the air outlet 42 towards the wall 33 of the intrados face 32 and the trailing edge 30.

[0048] This flared recess 50 allows for better distribution of the airflow exiting the orifices 42.

[0049] Advantageously, the recess 50 includes a projection face 52 which is oriented towards the wall 33 of the intrados face 32 and the trailing edge 30. This projection face 52 further improves the distribution of the airflow exiting the orifices 42, as seen in Figure 6.

[0050] Figure 6 shows a comparison of the distribution zones a, P of the airflow exiting an air outlet orifice 42 with and without a recess 50. When the bottom 44 of the tub 36 of the blade 20 does not have a recess 50 at the level of the air outlet orifice 42, i.e., the orifice 42 opens directly into the bottom 44 of the tub 36, the airflow exits in a first distribution zone a. When the bottom 44 of the tub 36 has a recess 50, and preferably with a projection face 52, the airflow exits in a second distribution zone p. It is observed that the first distribution zone a is smaller than the second distribution zone p. In other words, a better distribution of the airflow is obtained over a wider and more homogeneous area. This allows for better cooling of the intrados face 32 and the trailing edge 30 at the level of the free end 22a of the blade 22.

[0051] The recess 50 can have a general inverted pyramid shape, with its apex approximately centered on the air outlet 42. Furthermore, this inverted pyramid can have a triangular or polygonal base. It is understood that this base is located on the bottom side 44 of the bathtub 36. The projection face 52 is then one of the faces of this inverted pyramid.

[0052] The projection face 52 can be inclined relative to the bottom 44 of the bathtub 36 with an angle between 5 degrees and 60 degrees.

[0053] Figure 7 shows an axial cross-sectional view of the tip of the blade 20. In the example shown, the air outlet(s) 42 have an X-axis with a different angle of inclination than the angle of inclination of the projection face 52. A break in slope can thus be observed. It is preferred that the slope of the projection face 52 be shallower than the slope of the air outlet(s) 42. In other words, the angle of inclination of the projection face 52 is less than the angle of inclination of the air outlet(s) 42.

[0054] In other cases (not shown), the projection face 52 may be in line with the orifice 42. In other words, the angle of inclination of the projection face 52 may be substantially equal to the angle of inclination of the X axis of the air outlet orifice 42.

[0055] The angle of inclination of the projection face 52 is determined according to the desired specifications and the characteristics of the rotor blade 20.

[0056] When the recess 50 has the shape of an inverted pyramid, the projection face 52 has a triangular shape, the apex of which, located at the air outlet 42, can form an angle between 10 degrees and 60 degrees. This allows for the formation of a distribution zone for the airflow exiting the orifice 42, oriented towards the wall 33 of the intrados face 32 and the trailing edge 30. Advantageously, the flow distribution zone extends over an angular range substantially equal to the angle formed by the triangular projection face 52.

[0057] The awl 20 may include at least one dust removal orifice 60 at the bottom 44 of the tub 36. This dust removal orifice 60 is designed to allow the evacuation of foreign bodies which may accumulate in the internal circuit 38.

[0058] The dust extraction port(s) 60 may have a cross-section larger than the cross-section of the air outlet port(s) 42. In other words, a dust extraction port 60 is larger than an air outlet port 42.

[0059] The blade 20 according to the invention may include at least two air outlet orifices 42.

[0060] The invention also relates to a turbine 10 for an aircraft turbomachine comprising several blades 20 as described above. These blades 20 are mounted side by side on a rotor disc 18, by fitting their feet 24 into recesses on the outer periphery of the rotor disc 18.

[0061] In light of the foregoing, the invention offers the advantage of improved cooling of the free end of the blade. Indeed, since the air outlet(s) are oriented towards the wall of the lower surface and the trailing edge, i.e., in a non-radial manner, the escaping airflow is advantageously directed towards those parts of the blade that are most affected by the temperature effects of the hot air flow from the duct. In other words, the airflow generated by the internal ventilation air passage circuit of the blade, and exiting through the air outlet(s), is directed towards a hot area of ​​the tub in order to allow an improvement of local heat exchanges to improve cooling and thus reduce blade degradation and slow down its aging.

[0062] The aforementioned advantage is further enhanced when the bottom of the bathtub features a recess at the opening of each air vent, flaring outwards from the vent towards the back wall and trailing edge. This design increases the area where the airflow from the vent is distributed, resulting in improved cooling.

Claims

Demands [1] Rotor blade (20) for an aircraft turbomachine, said blade (20) comprising a blade (22) and a foot (24) connected to the blade (22) by a platform (26), said blade (22) extending from the platform (26) to a free end (22a) opposite the platform (26), along an axis of length (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 walls (33, 35) 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 (42) formed in the bottom (44) of said tub (36), said at least one air outlet (42) extending along an axis (X) not parallel to said axis of elongation (A), said at least one outlet (42) being oriented towards the wall (33) of said intrados face (32) and the trailing edge (30) when said at least one outlet (42) opens into the bottom of said tub (36), said bottom of the tub (36) having, at the level of the opening of each outlet (42) into the tub, a recess (50) which flares out from the opening of the outlet (42) towards the wall (33) of the intrados face (32) and the trailing edge (30), said recess having a general inverted pyramid shape whose apex is substantially centered on said outlet (42) and comprising a face projection (52) which is oriented towards the wall (33) said intrados face (32) and the trailing edge (30),said projection face (52) having a triangular shape whose apex, located at the level of the orifice (42), forms an angle between 10 and 60 degrees so as to form a distribution zone for an airflow exiting the orifice (42) oriented towards the wall (33) of the intrados face (32) and the trailing edge (30). [2] Blade (20) according to claim 1, wherein said at least one orifice (42) has a generally cylindrical shape. [3] Blade (20) according to any one of claims 1 or 2, wherein the axis (X) not parallel to the elongation axis (A) is inclined relative to the bottom (44) of the tub (36) with an angle of inclination between 15 degrees and 80 degrees. [4] Blade (20) according to any one of claims 1 to 3, wherein said inverted pyramid has a triangular or polygonal base. [5] Blade (20) according to any one of claims 1 to 4, wherein said projection face (52) is inclined relative to the bottom (44) of the tub (36) with an angle of inclination between 5 degrees and 60 degrees. [6] Blade (20) according to any one of claims 1 to 5, wherein said at least one orifice (42) is located equidistant from the walls (33, 35) of said intrados and extrados faces (32, 34) surrounding the tub (36) and is located at a distance from a longitudinal end (37) of the tub (36), located on the trailing edge side (30). [7] Blade (20) according to any one of claims 1 to 6, comprising at least two air outlet ports. [8] Blade (20) according to any one of claims 1 to 7, comprising at least one dust removal orifice at the bottom of the tub. [9] Blade (20) according to claim 8, wherein said at least one dust removal orifice has a cross-section whose dimension is greater than the dimension of a cross-section of the air outlet orifice. [10] Turbine (10) for an aircraft turbomachine, comprising several blades (20) according to any one of claims 1 to 9 which are mounted side by side on a rotor disc (18), by fitting their feet (24) into recesses in an outer periphery of the rotor disc (18).

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