BLADE FOR AN AIRCRAFT TURBOMACHINE AND METHOD FOR MANUFACTURING THE BLADE

Abstract

The invention relates to a blade (6, 7) for an aircraft turbomachine, the blade (6, 7) comprising: - a blade (9) having a pressure face (11i) and an extrados face (11e) connected by a leading edge (11a) and a trailing edge (11b), the blade (9) comprising a first metallic material, - at least one heating line (13) extending along the blade (9), the heating line (13) comprising at least one electrically conductive body (17) comprising a second metallic material, characterized in that the heating line (13) is integrated into the blade (9) and forms with the blade (9) a monolithic assembly. Abstract figure: 2

Description

Title of the invention: BLADE FOR AN AIRCRAFT TURBOMACHINE AND METHOD FOR MANUFACTURING THE BLADE Technical field of the invention

[0001] The invention relates to the field of blades for aircraft turbomachines. The invention relates in particular to the field of blades presenting a risk of ice or frost formation.

[0002] The invention further relates to the field of manufacturing methods for these blades. Technical background

[0003] An aircraft turbomachine generally extends along and around a longitudinal axis. It comprises a gas generator which typically comprises from upstream to downstream, in the direction of flow of the gases in the turbomachine, a low pressure compressor, a high pressure compressor, a gas combustion chamber, a high pressure turbine and a low pressure turbine.

[0004] The rotor of the low pressure compressor is typically connected to the rotor of the low pressure turbine via a low pressure shaft. The rotor of the high pressure compressor is connected to the rotor of the high pressure turbine via a high pressure shaft.

[0005] The turbomachine further comprises a fan which is located upstream of the gas generator. The fan comprises a rotor driven in rotation about the longitudinal axis by a fan shaft. The fan further comprises blades extending radially from the disk.

[0006] A blade typically comprises a blade having an aerodynamic shape. The blade thus comprises a pressure face and an extrados face which are connected by a leading edge and a trailing edge. The blade may be made of metallic material.

[0007] The blower promotes the suction of an air flow which is divided downstream of the blower into a primary air flow and a secondary air flow. The secondary air flow flows in an annular secondary vein and the primary air flow flows in an annular primary vein surrounded by the secondary vein. The secondary air flow is the source of the majority of the thrust of the turbomachine. The primary air flow is compressed within the compressors and then mixed with a fuel within the combustion chamber. The gases formed by the combustion then feed the turbines and make it possible to rotate the low-pressure shaft and consequently the low-pressure compressor.

[0008] Turbomachines are subject to risks of frost or even ice formation. Indeed, the temperature of the secondary airflow, which can reach negative temperatures, combined with the humidity of the air, are factors that favor the formation of frost and, ultimately, ice. For example, the blades of the turbomachine, particularly the fan blades, can carry blocks of ice. Such phenomena are particularly disruptive for the turbomachine since they can unbalance the balance of the turbomachine by creating, for example, an unbalance. Also, there is a risk that the ice penetrates into the primary flow and damages the internal components of the turbomachine, such as the compressors, by impact.

[0009] Therefore, there is a need to provide a blade for an aircraft turbomachine, the risk of frost or ice formation of which is limited or which allows the blade to be de-iced. Summary of the invention

[0010] For this purpose, the invention proposes a blade for an aircraft turbomachine, the blade comprising:

[0011] - a blade having an intrados face and an extrados face connected by an edge leading edge and a trailing edge, the blade comprising a first metallic material,

[0012] - at least one heating line extending along the blade, the heating line comprising at least one electrically conductive body comprising a second metallic material.

[0013] The blade according to the invention is remarkable in that the heating line is integrated into the blade and forms a monolithic assembly with the blade.

[0014] The electrically conductive body of the heating line allows, under the effect of the current, to generate heat by Joule effect. The blade is then heated by radiation which makes it possible to prevent or remove ice or frost from the blade.

[0015] According to the invention, the heating line and the blade form a monolithic assembly, that is to say an integral, homogeneous, single-piece and inseparable assembly. There is a continuity of material without voids or play between the blade and the heating line. Such a monolithic assembly is typically obtained by simultaneous additive manufacturing of the blade and the heating line.

[0016] Such a configuration of the blade makes it possible to dispense with a step of assembling the heating line with the blade. Indeed, such a step comprises sub-steps of first providing a housing for receiving the heating line in the blade, inserting the heating line into the blade, and closing the ends of the housing, whereas these steps are long, tedious and expensive.

[0017] The invention may comprise one or more of the following features, taken in isolation from one another or in combination with one another:

[0018] - the blade and the heating line are produced jointly by additive manufacturing,

[0019] - the heating line has first and second electrical connection ends intended to be connected to a source of electrical energy,

[0020] - the heating line has a diameter between 0.1 mm and 5 mm, preferably between 0.3 mm and 3 mm,

[0021] - the heating line and the leading edge are separated by a distance between 0.1 cm and 5 cm, preferably between 0.5 cm and 2 cm,

[0022] - the heating line further comprises an electrically insulating layer arranged around the electrically conductive body,

[0023] - the electrically insulating layer comprises a ceramic material, preferably alumina,

[0024] - the electrically insulating layer has a thickness of between 0.1 mm and 1 mm, preferably between 0.1 mm and 0.5 mm.

[0025] The invention also relates to a method for additively manufacturing a blade according to any one of the preceding characteristics.

[0026] The method according to the invention is remarkable in that it comprises the following steps:

[0027] (a) depositing on a support a layer comprising a first powder of the first metallic material and a second powder of the second metallic material,

[0028] (b) selectively fusing the first and second powders, and

[0029] (c) repeat steps (a) and (b) until the dawn is obtained.

[0030] The method may comprise one or more of the following features, taken in isolation from each other or in combination with each other:

[0031] - in step (a) the layer further comprises a third powder comprising a ceramic material and step (b) comprises selectively fusing the first and second powders.

[0032] The invention also relates to an assembly comprising at least one blade comprising any one of the above characteristics and an electrical power supply device comprising an electrical energy source connected to the heating line. Brief description of the figures

[0033] 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:

[0034] [Fig-1] [Fig.l] is a perspective view of an example of a turbomachine aircraft to which the invention can be applied;

[0035] [Fig.2] [Fig.2] is a perspective view of a blade according to the invention, in which the heating line is illustrated by transparency;

[0036] [Fig.3] [Fig.3] is a cross-sectional view of a heating line equipping the dawn of [Fig.2];

[0037] [Fig.4] [Fig.4] is a longitudinal sectional view of a blade according to an example of realization of the invention,

[0038] [Fig.5] [Fig.5] is a cross-sectional view of the blade of [Fig.4],

[0039] [Fig.6] [Fig.6] is a cross-sectional view of a blade according to another example of realization of the invention,

[0040] [Fig.7] [Fig.7] is a longitudinal sectional view of a blade according to another exemplary embodiment of the invention,

[0041] [Fig.8] [Fig.8] is a cross-sectional view of the blade of [Fig.7],

[0042] [Fig.9] [Fig.9] is a block diagram of a manufacturing process according to the invention,

[0043] [Fig. 10] [Fig. 10] is a diagram of an additive manufacturing installation that can be implemented in the method of the invention. Detailed description of the invention

[0044] An example of an aircraft turbomachine 1 according to the invention is shown in [Fig.l]. The turbomachine 1 is for example a dual-flow turboprop.

[0045] The turbomachine 1 extends along a longitudinal axis X. A gas flow F flows into the turbomachine 1.

[0046] For the purposes of the present invention, the terms “upstream” and “downstream” are understood to mean relative to the direction of flow of the gas flow F in the turbomachine 1 along the longitudinal axis X.

[0047] The terms “radial”, “radially”, “longitudinal”, “longitudinally”, “axial”, “axially”, are understood relative to the longitudinal axis X of the turbomachine 1.

[0048] The terms “internal”, “internally”, “externally”, “externally”, are understood in relation to the distance from the longitudinal axis X along an axis radial to the longitudinal axis X.

[0049] The turbomachine 1 comprises, from upstream to downstream, a fan 2 and a gas generator 3. The gas generator comprises, from upstream to downstream, a rectifier 4, a low-pressure compressor, a high-pressure compressor, at least one annular combustion chamber, a high-pressure turbine and a low-pressure turbine.

[0050] Each compressor comprises a compressor rotor and each turbine comprises a turbine rotor. The rotors typically comprise a movable wheel carrying blades regularly distributed around the longitudinal axis X. Each compressor further comprises a row of fixed blades rotating between each movable wheel. A movable wheel and a row of fixed blades constitute a compressor stage or turbines. The compressor rotor of the low-pressure compressor is connected to the turbine rotor of the low-pressure turbine by a low-pressure shaft. They form a low-pressure body.

[0051] The compressor rotor of the high-pressure compressor is connected to the turbine rotor of the high-pressure turbine by a high-pressure shaft (not shown). They form a high-pressure body.

[0052] The low pressure and high pressure shafts may be centered on the longitudinal axis X and are rotatable about the longitudinal axis X. The high pressure shaft is arranged coaxially around the low pressure shaft.

[0053] The fan 2 comprises a disk 5 centered on the longitudinal axis X and blades 6 extending radially from the disk 5 and regularly distributed around the longitudinal axis X. The disk 5 and the blades 6 are movable in rotation around the longitudinal axis X.

[0054] The fan 2 is particularly advantageously of the unducted type, also known by the English expression "open rotor". Unlike ducted type fans, the fan 2 is not surrounded by a fan casing surrounding the fan blades.

[0055] The rectifier 3 comprises blades 7 fixed in rotation about the longitudinal axis X. The blades 7 are regularly distributed about the longitudinal axis X. They are for example variable pitch. The blades 7 are thus movable in rotation about their axis of elongation Y which extends radially relative to the longitudinal axis X of the turbomachine 1. The blades 7 of the rectifier 3 are for example carried by a motor casing 8. The motor casing 8 is located downstream of the disk 5 and is connected to the latter. The motor casing 8 is annular and centered on the longitudinal axis X. It has an aerodynamic shape to facilitate the flow of the air flow downstream of the fan 2.

[0056] The turbomachine 1 is preferably a single unducted fan, also known by the English acronym USF for “Unducted Single Fan”. Unlike turbomachines with a contra-rotating fan, also known by the English acronym CROR for “Contra-Rotating Open Rotor”, the fan only comprises a single annular row of blades rotating around the longitudinal axis X. This type of configuration makes it possible to considerably reduce the mass of the turbomachine 1.

[0057] The gas flow F passes through the blower 2 and is divided into a primary air flow F1 passing through an annular primary vein located inside the engine casing 8 and into a secondary air flow F2 passing through an annular secondary vein located outside the engine casing 8.

[0058] The primary air flow Fl passes through the gas generator, and therefore successively through the low pressure and high pressure compressors. The compressed primary air flow Fl then passes through the combustion chamber in which it is mixed with a fuel. The gases from combustion thus pass through the high-pressure and low-pressure turbines. The energy of the gases is transformed by the turbine rotor of the low-pressure turbine into mechanical energy to rotate the low-pressure shaft and consequently the low-pressure compressor.

[0059] The secondary air flow F2 passes through the rectifier 3 which makes it possible to limit the rotation of the secondary air flow F2 at the outlet of the fan 2. The secondary air flow F2 makes it possible to generate the majority of the thrust of the turbomachine 1.

[0060] With reference to [Fig.2], each of the blades 6, 7 of the fan 2, of the rectifier 7 or of the first stage of the low-pressure compressor for example, comprises a blade 9 extending between two opposite ends 10a, 10b along an elongation axis Y of the blade 9. The blade 9 has an aerodynamic shape. It comprises an intrados face 11i and an extrados face 11e which are connected by a leading edge 11a and a trailing edge 11b. The leading and trailing edges 11a, 11b extend along the elongation axis Y of the blade 9. The leading and trailing edges 11a, 11b are connected by the intrados 11i and extrados 11e faces along a transverse axis Z perpendicular to the elongation axis of the blade 9. When mounted in the turbomachine 1, the axis Y of the blade 9 extends radially relative to the longitudinal axis X of the turbomachine 1 and the transverse axis Z extends substantially parallel to the longitudinal axis X of the turbomachine 1.

[0061] The blade 9 comprises and preferably consists of a first metallic material. The first metallic material comprises titanium or is made of titanium. It is for example chosen from titanium alloys, such as grade TA6V. Titanium has good tensile strength, good fatigue resistance and good impact resistance. According to another example, the first metallic material comprises aluminum, such as an aluminum alloy. The aluminum alloy is for example grade 7075.

[0062] The blade 9 has an external surface 12 swept by a cold air flow, such as the secondary air flow F2, and capable of forming frost or ice. The formation of frost or ice can create an imbalance and unbalance the turbomachine 1. Also, the frost or ice formed on these blades 6, 7 can enter the gas generator and cause serious damage.

[0063] In order to prevent the formation of ice or frost and / or to remove the ice or frost formed, the blade 6, 7 comprises at least one heating line 13 integrated into the blade 9. The heating line 13 is a defrosting or anti-frosting line for the blade 6, 7. By "defrosting", it is understood that the heating of the blade 9 makes it possible to remove or reduce the quantity of frost or ice previously formed and by "anti-frosting", it is understood that the heating of the blade 9 makes it possible to prevent or limit the risk of frost or ice forming on the external surface 12 of the blade 9.

[0064] According to the invention, the heating line 13 and the blade 9 form a monolithic assembly. By "integrated into the blade and forming a monolithic assembly", it is understood that the heating line 13 and the blade 9 form an integral, homogeneous, single-piece and inseparable assembly. There is therefore a continuity of material without voids or play between the blade 9 and the heating line 12. The heating line 13 integrated into the blade 9 and forming a monolithic assembly with the blade 9 therefore opposes a heating line arranged in the blade, the blade and the heating line each forming an assembly distinct from one another. Such a configuration of the invention makes it possible to avoid a step of assembling the heating line 9 in the blade 9 which is long, tedious and expensive.

[0065] According to a particularly preferred embodiment of the invention, the blade 9 and the heating line 13 are produced jointly by additive manufacturing. Joint additive manufacturing comprises the deposition of several layers, each layer being able to have two materials to produce both the blade 9 and the heating line 13. Such additive manufacturing therefore makes it possible to produce a monolithic assembly which comprises both the blade 9 and the heating line 13.

[0066] The heating line 13 extends along the blade 9 between the first and second ends 10a, 10b of the blade 9.

[0067] The heating line 13 is preferably located opposite the trailing edge 11b along the transverse axis Z of the blade 9. The risk of ice or frost formation is particularly high at the leading edge 11a of the blade 6, 7. This particular arrangement makes it possible to preferably heat the leading edge 11a to reduce the risk or reduce or even eliminate the ice or frost formed. The heating line 13 is for example separated from the leading edge 11a by a distance d, or a blade thickness 9 of between 0.1 cm and 5 cm, preferably between 0.5 cm and 2 cm as measured along the transverse axis Z.

[0068] The heating line 13 further comprises first and second electrical connection ends 14, 15. The first and second electrical connection ends 14, 15 are located opposite the first or second end 10a, 10b of the blade 9. The first and second electrical connection ends 14, 15 are thus located on the same side along the elongation axis Y of the blade 9.

[0069] With reference to [Fig. 3], the heating line 13 further comprises an electrically conductive body 17 and optionally an electrically insulating layer 18 arranged around the electrically conductive body 17. The electrically conductive body 17 extends from the first electrical connection end 14 to the second electrical connection end 15.

[0070] The electrically conductive body 17 comprises a second metallic material. The second metallic material has a resistivity of between 1 x 108 Qm and 2 x 108 Qm as measured at 20°C and an electrical conductivity of between 59 x 106 Sm-1 and 60 x 106 Sm-1 as measured at 20°C. Advantageously the second metallic material comprises copper, or consists of copper or consists of a copper alloy.

[0071] The electrically conductive body 17 ensures the passage of the electric current in the heating line 13 and heating by Joule effect.

[0072] The blade 9 being made of metallic material and therefore also being electrically conductive, the electric current also passes through the blade 9 not equipped with the heating line 13 causing heating by the Joule effect of the entire blade 9.

[0073] Depending on the heat input required by the blade 6, 7, the electrically conductive body 17 may be surrounded by the electrically insulating layer 18. The electrically insulating layer 18 makes it possible to limit the passage of the electric current in the blade 9 and to reserve this passage of electric current exclusively in the electrically conductive body 17. This makes it possible to promote the increase in the temperature of the blade 6, 7 in a localized manner and therefore in a more significant manner.

[0074] In particular, in the absence of an electrically insulating layer 18, the heating line 13 makes it possible to reach a temperature of the external surface 12 of 5°C when the temperature of the cold air flow is between -50°C and 20°C and the presence of the electrically insulating layer 18 makes it possible to reach a temperature of the external surface 12 of 5°C when the temperature of the cold air flow is between -120°C and 20°C.

[0075] The electrically insulating layer 18 extends from the first electrical connection end 14 to the second electrical connection end 15.

[0076] The electrically insulating layer 18 has a thickness of between 0.1 mm and 1 mm, preferably between 0.1 mm and 0.5 mm.

[0077] The electrically insulating layer 18 comprises a ceramic material. The ceramic material is preferably alumina, also known as aluminum oxide or molybdenum silicide.

[0078] The heating line 13 has a cross-section of circular shape as illustrated in [Fig.6] or elliptical as illustrated in [Fig.5]. It has a diameter of, for example, between 0.1 mm and 5 mm, preferably between 0.3 mm and 3 mm.

[0079] The heating line 13 further comprises line sections 16 connecting the first and second ends 14, 15 of the heating line to each other.

[0080] According to a first example illustrated in Figures 4 to 6, the first and second ends 14, 15 are each connected to a line section 16. Each line section 16 extends along the blade 9, parallel to the elongation axis Y between the first and second ends 10a and 10b of the blade 9. The line sections 16 are connected to each other opposite the first and second electrical connection ends. 14, 15 by an electric bridge 17.

[0081] According to a second example illustrated in Figures 7 and 8, the first and second ends 14, 15 are connected to a line section 16. The line section 16 may have a serpentine shape which extends between the leading edge 11a and the trailing edge 11b. This embodiment is particularly suitable when the blade 6, 7 must be heated over the entire external surface 12, that is to say on all the intrados 11i and extrados 11e faces from the leading edge 11a to the trailing edge 11b. In order to further optimize the heating, according to this example, the heating line 12 is equipped with the electrically insulating layer 18 described previously.

[0082] The heating line 13 is connected to an electrical supply device 20.

[0083] The electrical power supply device 20 typically comprises an electrical energy source 21 connected to the heating line 13. The electrical energy source has an input terminal 21a connected to the first electrical connection end 14 and an output terminal 21b connected to the second electrical connection end 15 of the heating line 13.

[0084] The electrical energy source 21 is for example a generator. The electrical energy source 21 is capable of delivering an electrical voltage making it possible to adjust the heating power of each blade 6, 7, for example between 20 V and 100 V.

[0085] The series and parallel arrangement of the blades 6, 7 makes it possible to adapt to the voltage of the electrical network, for example between 500V and 1000V, preferably 800V.

[0086] The heating line 13 has a maximum power of between 500 W and 1000 W, preferably between 600 W and 800 W.

[0087] The heating line 13 makes it possible to reach temperatures of 5°C when the temperature of the cold air flow is between -120°C and 20°C.

[0088] Depending on the requirements, the blade 6, 7 may comprise several heating lines 12 which may be electrically connected in parallel or in series. The turbomachine 1 may further comprise several blades 6, 7 with heating line 12 which may be connected to the same supply device 20.

[0089] A method of manufacturing the blade 6, 7 will now be described with reference to [Fig.9].

[0090] The blade 6, 7 is produced by additive manufacturing. The additive manufacturing process may be a powder bed fusion process. The powder bed fusion process may be a selective laser sintering process, also known by the acronym SLS for “Selective Laser Sintering”, or a selective laser melting process, also known by the acronym SLM for “Selective Laser Melting”, or an electron beam melting process, also known by the acronym EBM for “Electron Beam Melting”. According to another example, the process may be a laser metal deposition process also known as the English acronym LMD for “Laser Metal Deposition”.

[0091] The manufacturing process comprises the following steps:

[0092] (a) depositing on a support a layer comprising a first powder of the first metallic material and a second powder of the second metallic material,

[0093] (b) selectively fusing the first and second powders, and

[0094] (c) repeat steps (a) and (b) until dawn 6, 7 is obtained.

[0095] In step (a), each deposited layer comprises a first powder and a second powder respectively comprising the first and second metallic materials of the blade 9 and of the heating line 13.

[0096] Each layer has a thickness for example between 20 μm and 60 μm.

[0097] The first and second powders are respectively deposited from a first and second reservoir 106, 108 of metal powder.

[0098] During step (b), after the deposition of each layer, each powder is selectively fused to form the blade 9 and the heating line 13 simultaneously and jointly.

[0099] The fusion can be carried out by laser or by an electron beam. The laser has a power for example between 200W and 1000W and a speed for example between 500 mm / s and 2000 mm / s.

[0100] The method may comprise a following preliminary step (i):

[0101] (i) providing a 3D model of the blade 6, 7.

[0102] The deposition step (a) and the fusion step (b) are then carried out according to the spatial coordinates of the model obtained in step (i).

[0103] Steps (a) and (b) are repeated until blade 6, 7 is obtained.

[0104] When the heating line 13 comprises the electrical insulation layer 18, step (a), the layer comprises a third powder comprising the ceramic material.

[0105] In step (b), the third powder is not fused by the laser or the electron beam. This makes it possible to preserve the electrical insulation properties of the electrical insulation layer 18.

[0106] The method can be implemented in an additive manufacturing installation 100 illustrated for example in [Fig. 10].

[0107] The installation 100 comprises a support 102 for manufacturing the blade 6, 7. The support 102 may for example be metallic. It may be fixed or movable in translation and / or rotation.

[0108] The installation 100 further comprises a tank 104 comprising a first powder reservoir 106 and a second powder reservoir 108 respectively comprising the first and second powders of the first and second metallic materials. The tank 104 can be movable in translation as indicated by the arrow.

[0109] The installation 100 further comprises a fusion device 110 such as a laser. The fusion device 110 can also be movable in translation.

Claims

Claims

1. Blade (6, 7) for an aircraft turbomachine (1), the blade (6, 7) comprising: - a blade (9) having an intrados face (1 li) and an extrados face (lie) connected by a leading edge (1 la) and a trailing edge (11b), the blade (9) comprising a first metallic material, - at least one heating line (13) extending along the blade (9), the heating line (13) comprising at least one electrically conductive body (17) comprising a second metallic material, characterized in that the heating line (13) is integrated into the blade (9) and forms with the blade (9) a monolithic assembly.

2. Blade according to the preceding claim, characterized in that the blade (9) and the heating line (13) are produced jointly by additive manufacturing.

3. Blade according to the preceding claim, characterized in that the heating line (13) has first and second electrical connection ends (14, 15) intended to be connected to an electrical energy source (21).

4. Blade according to any one of the preceding claims, characterized in that the heating line (13) has a diameter of between 0.1 mm and 5 mm, preferably between 0.3 mm and 3 mm.

5. Blade according to any one of the preceding claims, characterized in that the heating line (13) and the leading edge (11a) are separated by a distance of between 0.1 cm and 5 cm, preferably between 0.5 cm and 2 cm.

6. A blade according to any one of the preceding claims, characterized in that the heating line (13) further comprises an electrically insulating layer (18) arranged around the electrically conductive body (17).

7. A blade according to any one of the preceding claims, characterized in that the electrically insulating layer (18) comprises a ceramic material, preferably alumina.

8. Blade according to one of claims 5 or 6, characterized in that the electrically insulating layer (18) has a thickness of between 0.1 mm and 1 mm, preferably between 0.1 mm and 0.5 mm.

9. Method for additive manufacturing of a blade (6, 7) according to any one of the preceding claims, characterized in that it comprises the next steps: (a) depositing on a support (102) a layer comprising a first powder of the first metallic material and a second powder of the second metallic material, (b) selectively fusing the first and second powders, and (c) repeating steps (a) and (b) until the blade (6, 7) is obtained.

10. Method according to the preceding claim, characterized in that in step (a) the layer further comprises a third powder comprising a ceramic material and in that step (b) consists of selectively fusing the first and second powders.

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