Vane for an aircraft turbine engine, associated core and manufacturing method
Patent Information
- Application Number
- EP2024808702
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-10-31
- Filing Date
- 2024-10-24
- Publication Date
- 2026-09-09
AI Technical Summary
Existing cooling systems for aircraft turbomachine blades are insufficient in providing effective cooling, leading to potential overheating and oxidation of the blades due to limited airflow through internal cavities and perpendicular channels.
The design incorporates additional second air outlet mouths in the internal wall of the blade, oriented to promote airflow into internal channels by the coanda effect, enhancing the cooling efficiency of the external blade wall.
This configuration significantly increases the airflow into internal channels, improving the cooling efficiency of the blade's external wall and reducing the risk of overheating and oxidation.
Smart Images
Figure FR2024051406_08052025_PF_FP_ABST
Abstract
Description
[0001] DESCRIPTION
[0002] TITLE: BLADE FOR AN AIRCRAFT TURBOMACHINE, ASSOCIATED CORE AND MANUFACTURING METHOD
[0003] Technical field of the invention
[0004] The invention relates to the field of blades for aircraft turbomachines.
[0005] The invention relates in particular to the field of blades comprising internal cavities for the passage of a cooling air flow.
[0006] The invention also relates to the field of cores for the manufacture of these blades as well as the methods for manufacturing these blades.
[0007] Technical background
[0008] An aircraft turbomachine, such as a turbojet, typically comprises, from upstream to downstream in the direction of gas flow, a fan rotating about a longitudinal axis, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine and a gas exhaust nozzle.
[0009] The blower allows the suction of an air flow divided into a primary flow and a secondary flow. The primary flow passes through a primary vein of the turbomachine while the secondary flow is directed towards a secondary vein surrounding the primary vein.
[0010] The primary flow is compressed within the compressors. The compressed air is then mixed with fuel and burned within the combustion chamber. The gases from the combustion pass through the turbines and then escape through the nozzle, whose cross-section allows the acceleration of these gases to generate propulsion.
[0011] Turbines are typically equipped with blades regularly distributed around a rotating wheel about the longitudinal axis. A blade extends radially between a root and a tip. A blade also includes a blade connected to the root by a platform, for example. The blade has an outer wall with an aerodynamic shape typically comprising a pressure face and an extrados face connected by a leading edge and a trailing edge and an inner wall.
[0012] Because high-pressure turbine blades are located downstream of the combustion chamber, they are subjected to high temperatures. These blades are typically made of metal or composite materials, particularly ceramic matrix composites (CMCs). These materials have the advantage of being able to withstand high temperatures. However, such blades cannot be subjected to temperatures higher than those that metal or ceramic matrix composite materials can withstand.
[0013] In this context, it has been proposed to equip the blades with a cooling system in order to increase the temperature range in which these blades can be implemented. The cooling system comprises a cooling circuit arranged inside the blades and allowing the passage of air from the compressors inside the blades. The cooling circuit comprises internal cavities formed during the manufacture of the blades. Each internal cavity is delimited by the internal wall of the blade. In addition, it has been proposed to drill holes in the blade, in particular on the intrados or extrados face of the blade, and opening into the internal cavities to create a film of air around the blade. In order to increase the efficiency of this cooling system, it has been proposed to make at least one row of holes in the blade.
[0014] In order to improve the cooling efficiency of the blade, it has been proposed to optimize the configuration of these holes. The holes thus have an air outlet mouth arranged in the external wall of the blade and an internal channel connecting the outlet mouth to the internal cavity. The outlet mouth has a generally elongated shape towards the trailing edge so that the air film is as close as possible to the external wall of the blade and thus improve its cooling.
[0015] However, although improving the cooling of the blade, such a solution is not entirely satisfactory. Indeed, the internal channel has an axis perpendicular to the direction of flow of the air flow in the internal cavity. Such a configuration of the channel therefore limits the entry of the air flow into the channel and therefore the air flow exiting through the outlet.
[0016] Thus, despite the presence of this outlet, the quantity of cooling airflow exiting the internal cavity is insufficient to ensure effective cooling of the blades. The blade can then encounter high temperatures, and undergo oxidation favored by these high temperatures.
[0017] In this context, there is a need to provide a blade with improved cooling.
[0018] Summary of the invention
[0019] For this purpose, the invention proposes a blade for an aircraft turbomachine, the blade comprising:
[0020] - a blade extending along an axis of elongation and having an external wall comprising an intrados face and an extrados face connected by a leading edge and a trailing edge,
[0021] - at least one internal cavity for circulating a cooling air flow located in the blade and extending along the axis of elongation, the internal cavity being delimited by an internal wall of the blade,
[0022] - at least one first air outlet provided in at least one of the intrados and extrados faces,
[0023] - at least one internal channel connected to the first outlet mouth and extending along an axis transverse to the elongation axis.
[0024] The blade is remarkable in that said at least one internal channel is further connected to at least one second air outlet opening provided in the internal wall and opening into the internal cavity, the second outlet opening having a bottom wall connected to the internal channel and inclined relative to the axis of the internal channel, the second outlet opening having a generally trapezoidal or triangular shape and a flared shape in a direction substantially parallel to the axis of elongation, the second outlet opening further comprising side walls located on either side of the bottom wall from the internal wall.
[0025] Thus, the blade of the invention comprises second cooling air outlet vents arranged in the internal wall of the blade and opening into the internal cavity.
[0026] Thanks to the second outlet vents, the cooling air flow flowing into the internal cavity is preferentially directed towards the internal channel. Indeed, the inclined bottom wall of these second outlet vents promotes the deflection of the cooling air flow in the second outlet vents by Coanda effect. A greater quantity of cooling air flow thus flows into the internal channel, thus improving the cooling of the external wall of the blade.
[0027] The invention may comprise one or more of the following features, taken in isolation from each other or in combination with each other:
[0028] - the side walls are inclined towards the inside of the internal cavity,
[0029] - the side walls are inclined relative to the axis of elongation at an angle of between 30° and 60°,
[0030] - the second outlet has a curved wall connecting the side walls to each other and to the internal channel.
[0031] The invention also relates to a core for the manufacture by lost wax casting of a blade according to any one of the preceding characteristics, the core comprising a body extending along a main axis and defining a counterform of the internal cavity, the body having at least one protuberance defining a counterform of the second air outlet mouth, the protuberance having a main face inclined relative to the main axis and to an axis perpendicular to this main axis, the main face having a substantially trapezoidal or triangular shape, the protuberance further comprising two side walls connecting the body to the main face, the side walls being inclined relative to the main axis of the core.
[0032] The invention also relates to a method of manufacturing a blade according to any one of the above characteristics, the method comprising the following steps:
[0033] (a) providing a core defining a counterform of the internal cavity,
[0034] (b) make a model defining the external wall of the blade,
[0035] (c) arrange the core in the model,
[0036] (d) make a shell mold around the model, and
[0037] (f) pour a metal into the shell mold.
[0038] The method is remarkable in that in step (a) the core is according to any of the preceding characteristics.
[0039] Brief description of the figures
[0040] Other characteristics and advantages will emerge from the following description of non-limiting embodiments of the invention with reference to the appended drawings in which: Figure 1 is a schematic representation in longitudinal section of a half-turbomachine of an aircraft according to the invention, Figure 2 is a schematic representation of a blade according to the invention, Figure 3 is a schematic representation in cross section of the blade of Figure 2, Figure 4 is a schematic representation in perspective of a first outlet mouth of the blade of Figure 2, Figure 5 is a schematic representation in longitudinal section of the internal wall of the blade according to the invention in which a flow of cooling air flows, Figure 6 is another schematic representation of the internal wall of the blade according to the invention in which a flow of cooling air flows, Figure 7 is a block diagram of the method of the invention,Figure 8 is a schematic perspective representation of a core according to the invention for the manufacture of the blade.,
[0041] Detailed description of the invention
[0042] An example of an aircraft turbomachine 1 according to the invention is shown in FIG. 1. The turbomachine 1 extends around and along a longitudinal axis X.
[0043] In the present application, the terms “upstream” and “downstream” are defined in relation to the direction of circulation of the gases in the turbomachine 1 along the longitudinal axis X.
[0044] The terms “axial”, “axially”, “radial”, “radially”, “longitudinal”, “longitudinally”, are defined in relation to the longitudinal axis X of the turbomachine 1.
[0045] The terms "internal", "interior", "external", "exterior",
[0046] “externally” are defined relative to the distance from the longitudinal axis X of the turbomachine 1 along a radial axis.
[0047] The turbomachine 1 comprises, from upstream to downstream, a fan 2, at least one compressor such as a low pressure compressor 3 and a high pressure compressor 4, a combustion chamber 5, at least one turbine such as a high pressure turbine 6 and a low pressure turbine 7, and a nozzle (not shown).
[0048] The blower 2 allows the suction of an air flow F dividing into a primary air flow F1 and a secondary air flow F2. The primary air flow F1 passes through a primary vein of the turbomachine 1 while the secondary air flow F2 is directed towards a secondary vein surrounding the primary vein.
[0049] The primary air flow F1 is compressed within the low pressure compressor 3 then the high pressure compressor 4. The compressed air is then mixed with a fuel and burned within the combustion chamber 5. The gases formed by the combustion pass through the high pressure turbines 6 and low pressure turbines 7. The gases finally escape through the nozzle, the cross-section of which allows the acceleration of these gases to generate propulsion.
[0050] The fan 2 is for example shrouded. It is surrounded by an annular casing 2b centered on the longitudinal axis X. The casing 2b is for example surrounded by a nacelle (not shown) of the turbomachine 1.
[0051] With reference to Figure 2, the high-pressure turbine 6 comprises blades 8 extending radially from a disk (not shown) movable or fixed in rotation relative to the longitudinal axis X. Each blade 8 extends along an elongation axis Y between a head 10 and a root 12 mounted in the disk to retain the blade 8 on the disk. The elongation axis Y of the blade 8 extends radially relative to the longitudinal axis X of the turbomachine 1 when the blade 8 is mounted in the turbomachine 1.
[0052] Each blade 8 comprises a blade 14 extending along the elongation axis Y between the head 10 and the root 12. The blade 14 comprises an outer wall 16 and an inner wall 18 located inside the outer wall 16. The outer wall 16 has an aerodynamic shape and comprises a lower surface face 16i and an upper surface face 16e connected by a leading edge 16a and a trailing edge 16b.
[0053] The outer and inner walls 16, 18 are separated by a thickness e (shown in FIG. 3) of the blade 14 as measured along a transverse axis Z transverse to the elongation axis Y of the blade 8. This thickness e varies in the blade 8.
[0054] The blade 8 is made of an electrically conductive material. The material is, for example, a metallic material or a composite material. Advantageously, the composite material is a ceramic matrix composite (CMC) material. Such materials have the advantage of being resistant to high temperatures and therefore allowing the implementation of these blades near the combustion chamber 5, in an environment subject to high temperatures.
[0055] In order to further improve the temperature resistance of the blades 8, each blade 8 comprises a cooling system. With reference to FIG. 3, the cooling system comprises at least one internal cavity 20 for the circulation of a cooling air flow F3 (illustrated in FIG. 4). Advantageously, a plurality of internal cavities 20 are provided in the blade 8.
[0056] Each internal cavity 20 is located inside the blade 8 and advantageously extends along the elongation axis Y between the head 10 and the root 12 of the blade 8. Each internal cavity 20 is delimited or defined by the internal wall 18 of the blade 8.
[0057] The cooling air flow F3 is for example taken from the low pressure compressor 4 and is conveyed to the internal cavities 20.
[0058] In order to further improve the temperature resistance of the blades 8, the cooling system further comprises at least one first air outlet vent 22 provided in the outer wall 16. Advantageously, the blade 8 comprises a plurality of first air outlet vents 22 provided in the outer wall 16. The blade 8 advantageously comprises at least one row of first outlet vents 22 aligned along the elongation axis Y of the blade 8. The first outlet vents 22 may also be distributed in a staggered pattern.
[0059] Each first outlet mouth 22 comprises an elongated shape. Each first outlet mouth 22 has an elongated shape and flares towards the trailing edge 16b. Each first outlet mouth 22 has a substantially trapezoidal or triangular shape.
[0060] As best seen in Figure 4, each first outlet mouth 22 comprises a bottom wall 26 which extends from the outer wall 16 towards the inner wall 18 of the blade 8. The bottom wall 26 is inclined towards the inside of the blade 8. It is inclined from the outer wall 16 relative to the transverse axis Z and in a transverse plane P containing the extrados or intrados face 16e, 16i of the outer wall 16. Advantageously, the angle of inclination a of the bottom wall 26 as measured between the bottom wall 26 and the outer wall 16 in this plane is for example between 10° and 40°. Each first outlet mouth 22 further comprises a connecting wall 28 which extends from the outer wall 16 towards the inner wall 18 of the blade 8. The connecting wall 28 is connected to one end of the first outlet mouth 22 opposite the end to which the bottom wall 26 is connected. The connecting wall 28 is inclined towards the inside of the blade 8.It is inclined in the transverse plane P. Advantageously, the connecting wall 28 is inclined in this transverse plane P from the external wall 16 at an angle P of between 80° and 90°.
[0061] The first outlet vents 22 allow the passage of air from the internal cavity 20 to the external wall 16 of the blade 8 in order to create a film of air around the blade 8 to cool it. Such a configuration of the first outlet vents 22 makes it possible to create a film of air as close as possible to the external wall 16 in order to optimize its cooling.
[0062] The blade 8 further comprises at least one internal channel 30 which is connected to the first outlet mouth 22. Advantageously, the blade 8 comprises a plurality of internal channels 30, each internal channel 30 being respectively connected to a first outlet mouth 22. There are therefore as many internal channels 30 as there are first outlet mouths 22.
[0063] Each internal channel 30 advantageously has a tubular or cylindrical shape. In the present example, each internal channel 30 has a circular section. The section of each first outlet mouth 22 is greater than the section of each internal channel 30.
[0064] Each internal channel 30 has an air inlet end 30a and an air outlet end 30b connected to the first outlet vents 22. The bottom and connecting walls 26, 28 are connected to the outlet end 30b of the internal channel 30. Each internal channel 30 has an axis Z' parallel or inclined relative to the transverse axis Z. Advantageously, the axis Z' of each internal channel 30 is inclined relative to the transverse axis Z at an angle TT between 5° and 30°. The axis Z' of each internal channel 30 is inclined relative to the surfaces of the external and internal walls 16, 18.
[0065] According to the invention, each internal channel 30 is advantageously produced by electroerosion (EDM for “Electrical Discharge Machining” in English). Indeed, such a method is compatible with the aerodynamic shape of the blade 8 and makes it possible to guarantee the material health when drilling the internal channels 30. Each internal channel 30 could be produced by laser drilling or by casting.
[0066] With reference to Figure 5, the at least one internal channel 30 opens into the internal cavity 20 through at least one second air outlet opening 32. Advantageously, each internal channel 30 opens into the internal cavity 20 through a second outlet opening 32 respectively. The blade 8 thus comprises as many second outlet openings 32 as internal channels 30.
[0067] Each second outlet mouth 32 forms a recess in the thickness e of the blade 14. Each second outlet mouth 32 is formed in the internal wall 18 of the blade 8 and opens into a respective internal channel 30. The internal channels 30 thus connect the first and second outlet mouths 22, 32 to each other.
[0068] Advantageously, each second outlet mouth 32 has an elongated shape. Each second outlet mouth 32 has a shape that flares towards the inside of the internal cavity 20. Each second outlet mouth 32 has a generally trapezoidal or triangular shape. Each second outlet mouth 32 thus has a large base 32a upstream and a small base 32b downstream, the terms upstream and downstream being understood here according to the flow direction of the cooling air flow F3 in the internal cavity 20. According to the invention, each second outlet mouth 32 has a bottom wall 34 connected to the internal channel 30. The bottom wall 34 is inclined relative to the axis Z' of the internal channel 30. The bottom wall 34 is also inclined relative to the elongation axis Y of the blade 8 and of the internal cavity 20.The bottom wall 34 is inclined at an angle A of less than 90°, preferably between 5° and 80°, even more preferably between 5° and 45° as measured relative to the elongation axis Y. The bottom wall 34 extends the large base 32a towards the outside of the internal cavity 20.
[0069] Advantageously, each second outlet mouth 32 has a curved wall 36 which extends the small base 32b towards the outside of the internal cavity 20. The curved wall 36 is concave from the inside towards the outside of the internal cavity 20. The curved wall 36 is connected to the internal channel 30.
[0070] Advantageously, each second outlet mouth 32 further comprises two side walls 38 located on either side of the bottom wall 34 and extending from the internal wall 18. The side walls 38 widen in the direction of the internal cavity 20. In other words, they diverge from downstream to upstream with respect to the flow of the cooling air flow F3 in the internal cavity 20. The side walls are inclined with respect to the elongation axis Y at an angle advantageously between 30° and 60°.
[0071] Such second outlet vents 32 and in particular the presence of such a bottom wall 34 makes it possible to create a Coanda effect. This makes it possible to direct the cooling air flow F3 preferentially towards the internal channel 30 by promoting the deflection of this cooling air flow F3. Thanks to these second outlet vents 32, a greater quantity of cooling air flow F3 flows into the internal channel 30, thus making it possible to improve the cooling of the external wall 16 of the blade 8.
[0072] Preferably, the blade 8 comprises at least one row of second outlet openings 32 which are in particular aligned along the elongation axis Y of the blade 8. Even more preferably, the second outlet openings 32 are arranged on the upper part of the blade 8, the upper part being between the head 10 of the blade 8 and the point situated at an equal distance between the head 10 and the root 12 of the blade 8.
[0073] The blade 8 is more sensitive to thermal attacks in this upper part. Such a distribution of the second outlet vents 32 therefore makes it possible to optimize the cooling of the blade 8 in this part and to limit the thermal degradation of the blade 8.
[0074] The blade 8 is manufactured using a lost wax casting process. With reference to Figure 7, the process comprises the following steps:
[0075] (a) providing a core 100 defining a counterform of the internal cavity 20,
[0076] (b) optionally, fabricating a model defining the outer wall 16 of the blade 16,
[0077] (c) arrange the core 100 in the model,
[0078] (d) make a shell mold around the model,
[0079] (e) remove the model,
[0080] (f) pouring a metal into the shell mold,
[0081] (g) destroy the shell mold, and.
[0082] (h) remove core 100.
[0083] The method optionally comprises a step (i) for piercing the blade 8 so as to form the internal channel 30.
[0084] In step (b), the model advantageously comprises a wax. To maximize manufacturing yield, several models are made and organized in a cluster in order to simultaneously create several blades 8.
[0085] The shell mold includes a ceramic material.
[0086] Step (d) may include the following steps:
[0087] (dO) dip the model in a slip,
[0088] (d1) possibly, spray a powder on the model, such as sand, (d2) dry the model.
[0089] Steps (d0), (d1), (d2) can be repeated until a shell mold with sufficient mechanical characteristics is obtained. Step (e) of removing the model corresponds to a wax removal step. The shell mold is, for example, subjected to a temperature higher than the degradation temperature of the wax.
[0090] Next, step (f) of casting the metal is carried out in the shell mold. After the casting step, the metal is solidified. This makes it possible to form a casting blank of the blade 8.
[0091] After solidification, during step (g), the shell mold is destroyed by shocks for example. The core 100 is removed to form the internal cavity 20 of the blade 8.
[0092] Then, during step (i), the outer wall 16 of the blade 8 can be pierced to form the inner channel 30 connecting the first and second outlet mouths 22, 32. The outer wall 16 is pierced by electroerosion or laser drilling.
[0093] Alternatively, the internal channel 30 is formed by casting. The core 100 then has a counterform of the internal channel 30.
[0094] The core 100 according to the invention implemented in step (a) of the method will now be described.
[0095] As seen in Figure 8, the core 100 comprises a body 102 and at least one protrusion 104.
[0096] The body 102 has an elongated shape which extends along a main axis W corresponding to the elongation axis of the blade 8 after its manufacture. The body 102 is a counterform of the internal cavity 20 of the blade 8.
[0097] The protrusion 104 is located on the body 102. Advantageously, the core 100 comprises a plurality of protrusions 104 located on the body 102. The protrusions 104 are distributed along the main axis W of the core 100.
[0098] Each protrusion 104 defines a counterform of the second outlet openings 32. Each protrusion 104 extends projecting from the body 102. Each protrusion 104 has a generally trapezoidal or triangular shape. Each protrusion 104 thus comprises a main face 106 which has a substantially triangular or trapezoidal shape. The main face 106 has an end 106a which is connected to the body 102 of the core 100 and an opposite end 106b forming the apex of the main face 106. This opposite end 106b is intended to be connected to the internal channel 30. The main face 106 is located in a plane inclined relative to the main axis W of the core 100. Preferably, the main face 106 is inclined at an angle of between 5° and 45°.
[0099] Each protrusion 104 further comprises two lateral faces 108 extending projecting from the body 102 and on either side of the main face 106. The lateral faces 108 connect the body to the main face 106. Each lateral face 108 extends between the ends 106a, 106b of the lateral face 106.
[0100] Each protrusion 104 further comprises a curved face 110 connecting the apex 106b of the main face 106 to the body 102 of the core 100.
[0101] By implementing such a core 100, it is possible to manufacture the second outlet mouths 32 precisely while limiting the risks of poor positioning of these second outlet mouths 32.
[0102] The core 100 may comprise a counterform of the internal channel 30. This counterform is connected to the protuberance 104 by the opposite end 106b of the main face 106.
[0103] The first outlet mouth 22 may also be produced by casting. The shell mold may comprise a counterform of the first outlet mouth 22.
Claims
CLAIMS 1. Blade (8) for an aircraft turbomachine (1), the blade (8) comprising: - a blade (14) extending along an elongation axis (Y) and having an external wall (16) comprising an intrados face (16i) and an extrados face (16e) connected by a leading edge (16a) and a trailing edge (16b), - at least one internal cavity (20) for circulating a flow of cooling air (F3) located in the blade (14) and extending along the elongation axis (Y), the internal cavity (20) being delimited by an internal wall (18) of the blade (14), - at least one first air outlet (22) provided in at least one of the intrados and extrados faces (16i, 16e), - at least one internal channel (30) connected to the first outlet mouth (22) and extending along an axis (Z') transverse to the elongation axis (Y), characterized in that said at least one internal channel (30) is further connected to at least one second air outlet mouth (32) formed in the internal wall (18) and opening into the internal cavity (30), the second outlet mouth (32) having a bottom wall (34) connected to the internal channel (30) and inclined relative to the axis (Z') of the internal channel (30), the second outlet mouth (32) having a generally trapezoidal or triangular shape and a flared shape in a direction substantially parallel to the elongation axis (Y), the second outlet mouth (32) further comprising side walls (38) located on either side of the bottom wall (34) from the internal wall (18).
2. Blade according to the preceding claim, characterized in that the side walls (38) are inclined towards the inside of the internal cavity (20).
3. Blade according to the preceding claim, characterized in that the side walls (38) are inclined relative to the elongation axis (Y) at an angle of between 30° and 60°.
4. Blade according to any one of the preceding claims, characterized in that the second outlet mouth (32) has a curved wall (36) connecting the side walls (38) to each other and to the internal channel (30).
5. Core (100) for the manufacture by lost wax casting of a blade (8) according to any one of the preceding claims, the core (100) comprising a body (102) extending along a main axis (W) and defining a counter-shape of the internal cavity (20), the body (102) having at least one protuberance (104) defining a counter-shape of the second air outlet mouth (32), the protuberance (104) having a main face (106) inclined relative to the main axis (W) and to an axis perpendicular to this main axis (W), the main face (106) having a substantially trapezoidal or triangular shape and the protuberance (104) further comprising two side walls (108) connecting the body (102) to the main face (106), the side walls (106) being inclined relative to the main axis (W) of the core (100) .
6. Method of manufacturing a blade (8) according to any one of claims 1 to 4, the method comprising the following steps: (a) providing a core (100) defining a counterform of the internal cavity (20), (b) fabricating a model defining the outer wall (16) of the blade (14), (c) arrange the core (100) in the model, (d) make a shell mold around the model, and (f) casting a metal into the shell mold, characterized in that in step (a), the core (100) is according to claim 5.