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: - an airfoil (9) having a pressure face (11i) and a suction face (11e) which are connected by a leading edge (11a) and a trailing edge (11b), the airfoil (9) comprising a first metal material, - at least one heating line (13) extending along the airfoil (9), the heating line (13) comprising at least one electrically conductive body (17) comprising a second metal material, characterized in that the heating line (13) is integrated into the airfoil (9) and forms a monolithic assembly with the airfoil (9).

Description

[0001] DESCRIPTION

[0002] TITLE: BLADE FOR AN AIRCRAFT TURBOMACHINE AND METHOD FOR MANUFACTURING THE BLADE

[0003] Technical field of the invention

[0004] 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.

[0005] The invention also relates to the field of manufacturing methods for these blades.

[0006] Technical background

[0007] 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 gas flow in the turbomachine, a low-pressure compressor, a high-pressure compressor, a gas combustion chamber, a high-pressure turbine and a low-pressure turbine.

[0008] The low-pressure compressor rotor is typically connected to the low-pressure turbine rotor via a low-pressure shaft. The high-pressure compressor rotor is connected to the high-pressure turbine rotor via a high-pressure shaft.

[0009] The turbomachine further comprises a fan which is located upstream of the gas generator. The fan comprises a rotor rotated about the longitudinal axis by a fan shaft. The fan further comprises blades extending radially from the disc.

[0010] 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.

[0011] The fan promotes the suction of an air flow which is divided downstream of the fan 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 turbomachine's thrust. The primary air flow is compressed within the compressors and then mixed with fuel within the combustion chamber. The gases formed by the combustion then power the turbines and allow the low-pressure shaft and consequently the low-pressure compressor to rotate.

[0012] Turbomachines are subject to the risk of frost or even ice formation. Indeed, the temperature of the secondary airflow, which can reach negative temperatures, combined with the humidity in 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, for example by creating an unbalance. Also, there is a risk that ice will penetrate the primary flow and damage the internal components of the turbomachine, such as the compressors, by impact.

[0013] 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.

[0014] Summary of the invention

[0015] To this end, the invention proposes a blade for an aircraft turbomachine, the blade comprising: - a blade having an intrados face and an extrados face connected by a leading edge and a trailing edge, the blade comprising a first metallic material,

[0016] - at least one heating line extending along the blade, the heating line comprising at least one electrically conductive body comprising a second metallic material.

[0017] The blade according to the invention is remarkable in that the heating line is integrated into the blade and forms with the blade a monolithic assembly, the heating line having first and second electrical connection ends intended to be connected to a source of electrical energy.

[0018] The electrically conductive body of the heating line generates heat through the Joule effect under the effect of current. The blade is then heated by radiation, which helps prevent or remove ice or frost from the blade.

[0019] 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.

[0020] 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 includes 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, while these steps are long, tedious and expensive.

[0021] The invention may comprise one or more of the following features, taken in isolation from one another or in combination with one another: - the blade and the heating line are produced jointly by additive manufacturing,

[0022] - the heating line has a diameter between 0.1 mm and 5 mm, preferably between 0.3 mm and 3 mm,

[0023] - 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,

[0024] - the heating line further comprises an electrically insulating layer arranged around the electrically conductive body,

[0025] - the electrically insulating layer comprises a ceramic material, preferably alumina,

[0026] - the electrically insulating layer has a thickness of between 0.1 mm and 1 mm, preferably between 0.1 mm and 0.5 mm.

[0027] The invention also relates to a method for additively manufacturing a blade according to any one of the preceding characteristics.

[0028] The method according to the invention is remarkable in that it comprises the following steps:

[0029] (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,

[0030] (b) selectively fusing the first and second powders, and

[0031] (c) repeat steps (a) and (b) until you get the dawn.

[0032] The method may comprise one or more of the following features, taken in isolation from each other or in combination with each other:

[0033] - in step (a) the layer further comprises a third powder comprising a ceramic material and step (b) consists of selectively fusing the first and second powders. 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.

[0034] Brief description of the figures

[0035] 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:

[0036] [Fig.1] Figure 1 is a perspective view of an example of an aircraft turbomachine to which the invention can be applied;

[0037] [Fig.2] Figure 2 is a perspective view of a blade according to the invention, in which the heating line is illustrated by transparency;

[0038] [Fig.3] Figure 3 is a cross-sectional view of a heating line fitted to the blade of Figure 2;

[0039] [Fig. 4] Figure 4 is a longitudinal sectional view of a blade according to an exemplary embodiment of the invention,

[0040] [Fig. 5] Figure 5 is a cross-sectional view of the blade of Figure 4,

[0041] [Fig. 6] Figure 6 is a cross-sectional view of a blade according to another exemplary embodiment of the invention,

[0042] [Fig.7] Figure 7 is a longitudinal sectional view of a blade according to another exemplary embodiment of the invention,

[0043] [Fig.8] Figure 8 is a cross-sectional view of the blade of Figure 7, [Fig.9] Figure 9 is a block diagram of a manufacturing method according to the invention,

[0044] [Fig.10] Figure 10 is a diagram of an additive manufacturing installation that can be implemented in the method of the invention.

[0045] Detailed description of the invention An example of an aircraft turbomachine 1 according to the invention is shown in FIG. 1. The turbomachine 1 is for example a double-flow turboprop.

[0046] The turbomachine 1 extends along a longitudinal axis X. A gas flow F flows into the turbomachine 1.

[0047] 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.

[0048] The terms "radial", "radially", "longitudinal",

[0049] “longitudinally”, “axially”, “axially”, are understood in relation to the longitudinal axis X of the turbomachine 1.

[0050] 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.

[0051] 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.

[0052] Each compressor comprises a compressor rotor and each turbine comprises a turbine rotor. The rotors typically comprise a moving wheel carrying blades regularly distributed around the longitudinal axis X. Each compressor further comprises a row of fixed blades rotating between each moving wheel. A moving wheel and a row of fixed blades constitute a compressor or turbine stage. 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.

[0053] 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. The low-pressure and high-pressure shafts can 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.

[0054] The fan 2 comprises a disc 5 centered on the longitudinal axis X and blades 6 extending radially from the disc 5 and regularly distributed around the longitudinal axis X. The disc 5 and the blades 6 are rotatable around the longitudinal axis X.

[0055] 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.

[0056] 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 disc 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.

[0057] 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 comprises only 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. The gas flow F passes through the fan 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 F1 passes through the gas generator, and therefore successively through the low-pressure and high-pressure compressors. The compressed primary air flow F1 then passes through the combustion chamber, where it is mixed with fuel. The gases resulting from the 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, enabling the low-pressure shaft and, consequently, the low-pressure compressor to rotate.

[0059] The secondary air flow F2 passes through the rectifier 3 which limits the rotation of the secondary air flow F2 at the outlet of the fan 2. The secondary air flow F2 generates the majority of the thrust of the turbomachine 1.

[0060] With reference to Figure 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 a pressure 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 is made 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-icing 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-icing", 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 dispense with a step of assembling the heating line 9 in the blade 9 which is long, tedious and expensive. 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 involves 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 includes both the blade 9 and the heating line 13.

[0065] The heating line 13 extends along the blade 9 between the first and second ends 10a, 10b of the blade 9.

[0066] The heating line 13 is preferably located opposite the trailing edge 11 b along the transverse axis Z of the blade 9. The risk of ice or frost formation is particularly high at the leading edge 11 a of the blade 6, 7. This particular arrangement makes it possible to preferably heat the leading edge 11 a 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 11 a 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.

[0067] 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.

[0068] With reference to Figure 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.

[0069] The electrically conductive body 17 comprises a second metallic material. The second metallic material has a resistivity of between 1 x 10' 8 Qm and 2 x 10'8 Qm as measured at 20°C and an electrical conductivity between 59 x 10 6 Sm-1 and 60 x 10 6 Sm-1 as measured at 20°C. Advantageously the second metallic material comprises copper, or consists of copper or consists of a copper alloy.

[0070] The electrically conductive body 17 ensures the passage of the electric current in the heating line 13 and heating by Joule effect.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] The electrically insulating layer 18 extends from the first electrical connection end 14 to the second electrical connection end 15.

[0075] 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.

[0076] The electrically insulating layer 18 comprises a ceramic material. The ceramic material is preferably alumina, also known as aluminum oxide or molybdenum silicide. The heating line 13 has a cross-section of circular shape as illustrated in Figure 6 or elliptical as illustrated in Figure 5. It has a diameter of, for example, between 0.1 mm and 5 mm, preferably between 0.3 mm and 3 mm.

[0077] The heating line 13 further comprises line sections 16 connecting the first and second ends 14, 15 of the heating line to each other.

[0078] 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 electrical bridge 17.

[0079] 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 11 a and the trailing edge 11 b. 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 11 i and extrados 11 faces. efrom the leading edge 11 a to the trailing edge 11 b. In order to further optimize the heating, according to this example, the heating line 12 is equipped with the electrically insulating layer 8 described previously.

[0080] The heating line 13 is connected to a power supply device 20. The 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 21 a connected to the first electrical connection end 14 and an output terminal 21 b connected to the second electrical connection end 15 of the heating line 13.

[0081] 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.

[0082] 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.

[0083] The heating line 13 has a maximum power of between 500 W and 1000 W, preferably between 600 W and 800 W.

[0084] Heating line 13 allows temperatures of 5°C to be reached when the temperature of the cold air flow is between -120°C and 20°C.

[0085] 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. A method of manufacturing the blade 6, 7 will now be described with reference to FIG. 9.

[0086] The blade 6, 7 is made 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 by the acronym LMD for "Laser Metal Deposition".

[0087] The manufacturing process includes the following steps:

[0088] (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,

[0089] (b) selectively fusing the first and second powders, and (c) repeating steps (a) and (b) until blade 6, 7 is obtained.

[0090] In step (a), each deposited layer comprises a first powder and a second powder comprising respectively the first and second metallic materials of the blade 9 and of the heating line 13.

[0091] Each layer has a thickness of, for example, between 20 pm and 60 pm.

[0092] The first and second powders are respectively deposited from a first and second reservoir 106, 108 of metal powder.

[0093] 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.

[0094] Fusion can be achieved by laser or 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.

[0095] The method may comprise a preliminary step (i) as follows:

[0096] (i) provide a 3D model of the dawn 6, 7.

[0097] 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).

[0098] Steps (a) and (b) are repeated until dawn 6, 7 is obtained.

[0099] When the heating line 13 comprises the electrical insulation layer 18, in step (a), the layer comprises a third powder comprising the ceramic material.

[0100] In step (b), the third powder is not fused by the laser or the electron beam. This allows the electrical insulation properties of the electrical insulation layer 18 to be preserved.

[0101] The method can be implemented in an additive manufacturing installation 100 illustrated for example in FIG. 10.

[0102] 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. 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 may be movable in translation as indicated by the arrow.

[0103] 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 (11 i) and an extrados face (11 e) connected by a leading edge (11 a) and a trailing edge (11 b), 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, the heating line (13) having first and second electrical connection ends (14, 15) intended to be connected to an electrical energy source (21).

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 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.

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

5. 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).

6. Blade according to the preceding claim, characterized in that the electrically insulating layer (18) comprises a ceramic material, preferably alumina.

7. 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.

8. Method for additive manufacturing of a blade (6, 7) according to any one of the preceding claims, characterized in that it comprises the following 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) repeat steps (a) and (b) until you obtain dawn (6, 7).

9. 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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