Blade for aeronautical turbomachines and method for manufacturing a blade

Abstract

The present invention relates to a blade (6, 7) for an aircraft turbine, the blade (6, 7) comprising: - an airfoil (9) having a pressure surface (11i) and a suction surface (11e) connected by a leading edge (11a) and a trailing edge (11b), the airfoil (9) comprising a first metallic material; - at least one heating wire (13) extending along the airfoil (9), the heating wire (13) comprising at least one conductor (17) comprising a second metallic material, characterized in that the heating wire (13) is integrated in the airfoil (9) and forms an integral assembly with the airfoil (9).

Description

Technical Field

[0001] This invention relates to the field of fan blades for aircraft turbines. Specifically, this invention relates to the field of fan blades where there is a risk of icing or frosting.

[0002] The present invention also relates to the field of methods for manufacturing these fan blades. Background Technology

[0003] Aircraft turbines typically extend along and around a longitudinal axis. A turbine includes a gas generator, which, from upstream to downstream, typically comprises a low-pressure compressor, a high-pressure compressor, a gas combustion chamber, a high-pressure turbine, and a low-pressure turbine, all along the direction of gas flow within the turbine.

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

[0005] The turbine also includes a fan located upstream of the gas generator. The fan includes a rotor that rotates about a longitudinal axis and is driven by a fan shaft. The fan also includes fan blades that extend radially from the disk.

[0006] Fan blades typically consist of aerodynamically shaped blades. Therefore, a blade comprises a pressure surface and a suction surface connected by its leading and trailing edges. Blades can be made of metallic materials.

[0007] The fan helps draw in airflow, which splits into primary and secondary airflow downstream of the fan. The secondary airflow flows in an annular secondary bypass duct, while the primary airflow flows in an annular primary bypass duct surrounded by the secondary bypass duct. The secondary airflow is the source of most of the turbine's thrust. The primary airflow is compressed within the compressor and then mixed with fuel in the combustion chamber. The resulting gases are then supplied to the turbine to drive the low-pressure shaft, which in turn drives the low-pressure compressor.

[0008] Turbines are at risk of frosting and icing. In fact, the combination of secondary airflow temperature (which can often reach sub-zero temperatures) and humidity is a favorable factor for frosting and eventually icing. For example, turbine blades, particularly fan blades, can carry ice. This phenomenon is particularly destructive to turbines because it can disrupt their balance by creating imbalances, for example. There is also a risk that ice can penetrate the main bypass duct and damage internal turbine components, such as the compressor, through impact.

[0009] Therefore, there is a need for a fan blade for an aircraft turbine that has a limited risk of frost or icing, or that enables de-icing of the fan blade. Summary of the Invention

[0010] Therefore, the present invention proposes a fan blade for an aircraft turbine, the fan blade comprising: - Blade, the blade having a pressure surface and a suction surface connected by a leading edge and a trailing edge, the blade comprising a first metallic material. - At least one heating wire, the heating wire extending along the blade, the heating wire including at least one conductor comprising a second metallic material.

[0011] The unusual feature of the fan blade according to the invention is that the heating wire is integrated into the blade and forms an integral assembly with the blade, and the heating wire has a first electrical connection terminal and a second electrical connection terminal intended to be connected to an electrical energy source.

[0012] The conductors in the heating wire generate heat through the Joule effect under the influence of an electric current. The blades are then heated by radiation, which prevents ice or frost from forming on the blades or removes ice or frost from them.

[0013] According to the present invention, the heating wire and the blade form an integral assembly, that is, a one-piece, uniform, monolithic, and inseparable assembly. The material is continuous, and there are no gaps between the blade and the heating wire. Such an integral assembly is typically obtained by simultaneously additive manufacturing the blade and the heating wire.

[0014] This type of fan blade construction eliminates the need to assemble the heating wire to the blade. Such a process involves the following sub-steps: first, creating a housing for the heating wire in the blade, inserting the heating wire into the blade, and sealing the end of the housing, although these steps are lengthy, tedious, and expensive.

[0015] The present invention may include one or more of the following characteristics, either individually or in combination thereof: - The blades and heating wires are manufactured together using additive manufacturing. - The diameter of the heating wire is between 0.1mm and 5mm, preferably between 0.3mm and 3mm. - The heating wire is separated from the leading edge by a distance between 0.1cm and 5cm, preferably between 0.5cm and 2cm. - The heating wire also includes an electrically insulating layer arranged around the conductor. - The electrical insulating layer comprises a ceramic material, preferably alumina. - The thickness of the electrical insulation layer is between 0.1 mm and 1 mm, preferably between 0.1 mm and 0.5 mm.

[0016] The present invention also relates to a method for additive manufacturing of fan blades, the fan blades being fan blades according to any one of the foregoing characteristics.

[0017] The unusual aspect of the method according to the invention is that it includes the following steps: (a) Depositing a layer on a substrate comprising a first powder of a first metallic material and a second powder of a second metallic material. (b) Selectively melting the first powder and the second powder, and (c) Repeat steps (a) and (b) until the fan blades are obtained.

[0018] The method may include one or more of the following characteristics, either individually or in combination: - In step (a), the layer further includes a third powder containing ceramic material, and step (b) involves selectively melting the first powder and the second powder.

[0019] The present invention also relates to a component comprising at least one fan blade and a power supply device, wherein the at least one fan blade comprises any of the characteristics described above, and the power supply device comprises a power source connected to a heating wire. Attached Figure Description

[0020] Further features and advantages will become apparent from the following description of non-limiting embodiments of the invention with reference to the accompanying drawings, in which: [ Figure 1 ] Figure 1 This is a perspective view of an example of an aircraft turbine to which the present invention can be applied. [ Figure 2 ] Figure 2 This is a perspective view of the fan blade according to the invention, wherein the heating wire is shown in a transparent manner. [ Figure 3 ] Figure 3 Is it installed to Figure 2 A cross-sectional view of the heating wires on the fan blades. [ Figure 4 ] Figure 4 This is a longitudinal cross-sectional view of a fan blade according to an example of the present invention. [ Figure 5 ] Figure 5 yes Figure 4 A cross-sectional view of the fan blades. [ Figure 6 ] Figure 6 A cross-sectional view of a fan blade according to another embodiment of the present invention is shown. [ Figure 7 ] Figure 7 This is a longitudinal cross-sectional view of a fan blade according to another embodiment of the present invention. [ Figure 8 ] Figure 8 yes Figure 7 A cross-sectional view of the fan blades. [ Figure 9 ] Figure 9 This is a block diagram of the manufacturing method according to the present invention. [ Figure 10 ] Figure 10 This is a diagram of an additive manufacturing apparatus that can be used in the method of the present invention. Detailed Implementation

[0021] An example of the aircraft turbine 1 according to the present invention is shown in Figure 1 As shown in the diagram. For example, turbine 1 is a two-flow turboprop engine.

[0022] Turbine 1 extends along the longitudinal axis X. Gas flow F flows in turbine 1.

[0023] For the purposes of this invention, the terms “upstream” and “downstream” are understood in relation to the flow direction of the gas flow F in turbine 1 along the longitudinal axis X.

[0024] The terms “radial,” “radially,” “longitudinal,” “longitudinal,” “axial,” and “axially” refer to the longitudinal axis X of turbine 1.

[0025] The terms “internal,” “internally,” “externally,” and “externally” are understood in relation to the distance of the axis radially to the longitudinal axis X from the longitudinal axis X.

[0026] Turbine 1 includes a fan 2 and a gas generator 3 from upstream to downstream. The gas generator includes a stator 4, a low-pressure compressor, a high-pressure compressor, at least one annular combustion chamber, a high-pressure turbine, and a low-pressure turbine from upstream to downstream.

[0027] Each compressor includes a compressor rotor, and each turbine includes a turbine rotor. The rotor typically includes a rotor wheel that carries blades evenly distributed around a longitudinal axis X. Each compressor also includes a row of fixed rotating blades located between each rotor wheel. The rotor wheel and the row of fixed blades constitute a compressor or turbine stage. The compressor rotor of a low-pressure compressor is connected to the turbine rotor of a low-pressure turbine via a low-pressure shaft. They form the low-pressure body.

[0028] The compressor rotor of the high-pressure compressor is connected to the turbine rotor of the high-pressure turbine via a high-pressure shaft (not shown). They form the high-pressure body.

[0029] The low-pressure shaft and the high-pressure shaft can rotate around the longitudinal axis X. The high-pressure shaft is arranged coaxially around the low-pressure shaft.

[0030] Fan 2 includes a disk 5 centered on a longitudinal axis X and fan blades 6 extending radially from the disk 5 and evenly distributed around the longitudinal axis X. The disk 5 and fan blades 6 can move in a rotational manner around the longitudinal axis X.

[0031] Particularly advantageous is that fan 2 is an open rotor type fan. Unlike crowned fans, fan 2 is not surrounded by a fan housing to enclose the fan blades. Stator 3 includes fan blades 7 fixed in relation to rotation about the longitudinal axis X. The fan blades 7 are evenly spaced about the longitudinal axis X. For example, the fan blades 7 have variable spacing. Thus, the fan blades 7 can rotate about their extension axis Y, which extends radially relative to the longitudinal axis X of turbine 1. For example, the fan blades 7 of stator 3 are supported by engine housing 8. Engine housing 8 is located downstream of and connected to disk 5. Engine housing 8 is annular and centered on the longitudinal axis X. Engine housing 8 is aerodynamically shaped to facilitate airflow downstream of fan 2.

[0032] Preferably, turbine 1 is a ductless single fan (USF). Unlike turbines with counter-rotating fans (also known as those using the acronym CROR, meaning "counter-rotating open rotor"), the fan consists of only a single annular row of blades that can rotate about the longitudinal axis X. This type of construction significantly reduces the weight of turbine 1.

[0033] The gas flow F passes through the fan 2 and is divided into a main air flow F1 and a secondary air flow F2. The main air flow F1 passes through the main annular duct located inside the engine housing 8, and the secondary air flow F2 passes through the secondary annular duct located outside the engine housing 8.

[0034] The main airflow F1 passes through the gas generator, and thus sequentially through the low-pressure compressor and the high-pressure compressor. The compressed main airflow F1 then passes through the combustion chamber, where it mixes with the fuel. The combustion gases then pass through the high-pressure turbine and the low-pressure turbine. The energy of the gases is converted into mechanical energy by the turbine rotor of the low-pressure turbine, which allows the low-pressure shaft to rotate, and thus the low-pressure compressor to rotate.

[0035] The secondary airflow F2 passes through the stator 3, which restricts the movement of the secondary airflow F2 at the outlet of the fan 2. The secondary airflow F2 generates most of the thrust of the turbine 1.

[0036] refer to Figure 2Each of the fan blades 6, 7 in the fan 2, stator 7, or first low-pressure compressor stage includes, for example, a blade 9 extending along its elongation axis Y between two opposing ends 10a, 10b. The blade 9 has an aerodynamic shape. The blade 9 includes a pressure surface 11i and a suction surface 11e connected by a leading edge 11a and a trailing edge 11b. The leading edge 11a and trailing edge 11b extend along the elongation axis Y of the blade 9. The leading edge 11a and trailing edge 11b are connected by the pressure surface 11i and the suction surface 11e along a transverse axis Z perpendicular to the elongation axis of the blade 9. When the blade 9 is mounted in the turbine 1, the axis Y of the blade 9 extends radially relative to the longitudinal axis X of the turbine 1, and the transverse axis Z extends substantially parallel to the longitudinal axis X of the turbine 1.

[0037] The blade 9 comprises a first metallic material, preferably composed of a first metallic material. The first metallic material includes or is composed of titanium. For example, a titanium alloy, such as TA6V grade. Titanium has good tensile strength, fatigue strength, and impact strength. In another example, the first metallic material includes aluminum, such as an aluminum alloy. For example, an aluminum alloy of grade 7075.

[0038] Blade 9 has an outer surface 12 that is swept by a cold airflow, such as a secondary airflow F2, and is prone to frost or ice formation. Frost or ice formation can create imbalance and cause turbine 1 to become unbalanced. Furthermore, frost or ice formed on these blades 6, 7 can enter the gas generator and cause serious damage.

[0039] To prevent icing or frost formation and / or remove any formed ice or frost, fan blades 6 and 7 include at least one heating wire 13 integrated into the blade 9. The heating wire 13 is a de-icing or anti-icing wire for the fan blades 6 and 7. "De-icing" means that heating the blade 9 removes or reduces the amount of previously formed frost or ice, while "anti-icing" means that heating the blade 9 prevents or limits the risk of frost or ice formation on the outer surface 12 of the blade 9.

[0040] According to the present invention, the heating wire 13 and the blade 9 form an integral assembly. The phrase "integrated into the blade and forming an integral assembly" should be understood to mean that the heating wire 13 and the blade 9 form a single, uniform, monolithic, and inseparable assembly. Therefore, the material is continuous, and there are no gaps between the blade 9 and the heating wire 12. Thus, the heating wire 13 is integrated into the blade 9 and forms an integral assembly with the blade 9, which is the opposite of the heating wire being arranged in the blade, where the blade and the heating wire each form a separate assembly. This construction of the present invention eliminates the time-consuming, cumbersome, and expensive step of assembling the heating wire 9 in the blade 9.

[0041] In a particularly preferred embodiment of the invention, the blade 9 and the heating wire 13 are jointly produced by additive manufacturing. Additive manufacturing involves the deposition of multiple layers, each of which can be made of two materials to produce both the blade 9 and the heating wire 13. Therefore, this additive manufacturing enables the production of an integral assembly comprising both the blade 9 and the heating wire 13.

[0042] The heating wire 13 extends along the blade 9 between the first end 10a and the second end 10b of the blade 9.

[0043] Preferably, the heating wire 13 is positioned relative to the trailing edge 11b along the transverse axis Z of the blade 9. The risk of icing or frost formation is particularly high at the leading edge 11a of the blades 6 and 7. This specific arrangement enables heating of the leading edge 11a to reduce, limit, or even eliminate the formed ice or frost. For example, the heating wire 13 is separated from the leading edge 11a by a distance d, or the thickness of the blade 9, as measured along the transverse axis Z, which is between 0.1 cm and 5 cm, preferably between 0.5 cm and 2 cm.

[0044] The heating wire 13 also includes a first electrical connection terminal 14 and a second electrical connection terminal 15. The first electrical connection terminal 14 and the second electrical connection terminal 15 are positioned opposite to the first end 10a or the second end 10b of the blade 9. Therefore, the first electrical connection terminal 14 and the second electrical connection terminal 15 are located on the same side along the elongation axis Y of the blade 9.

[0045] refer to Figure 3 The heating wire 13 also includes a conductor 17, and optionally, the heating wire 13 further includes an electrically insulating layer 18 arranged around the conductor 17. The conductor 17 extends from the first electrical connection terminal 14 to the second electrical connection terminal 15.

[0046] Conductor 17 comprises a second metallic material. The resistivity of the second metallic material, as measured at 20°C, is between 1 × 10⁻⁶. -8 Ω.m to 2×10 -8 The conductivity of the second metallic material is between Ω·m, and, if measured at 20°C, between 59 × 10⁻⁶. 6 Sm-1 to 60×10 6 Between Sm-1. Advantageously, the second metallic material comprises copper, or is composed of copper, or is composed of copper alloys.

[0047] Conductor 17 ensures that current flows through heating wire 13 and heating is achieved through the Joule effect.

[0048] Since blade 9 is made of metal, it is also conductive, so the current also passes through blade 9 without heating wire 13, thereby heating the entire blade 9 by the Joule effect.

[0049] Depending on the required heat input of the fan blades 6 and 7, the conductor 17 can be surrounded by an electrically insulating layer 18. The electrically insulating layer 18 restricts the flow of current through the blades 9 and restricts the current to flow only to the conductor 17. This helps to increase the temperature of the fan blades 6 and 7 locally and thus more significantly.

[0050] Specifically, in the absence of the electrical insulation layer 18, when the temperature of the cold air flow is between -50°C and 20°C, the heating wire 13 can achieve a temperature of 5°C on the outer surface 12. However, with the electrical insulation layer 18 present, when the temperature of the cold air flow is between -120°C and 20°C, the temperature of the outer surface 12 can also be achieved at 5°C.

[0051] The electrical insulation layer 18 extends from the first electrical connection terminal 14 to the second electrical connection terminal 15.

[0052] The thickness of the electrical insulation layer 18 is between 0.1 mm and 1 mm, preferably between 0.1 mm and 0.5 mm.

[0053] The electrical insulating layer 18 comprises a ceramic material. Preferably, the ceramic material is alumina (also known as aluminum oxide) or molybdenum silicide.

[0054] Heating wire 13 has such Figure 6 The circular cross section shown or as Figure 5 The elliptical cross-section is shown. The diameter of the heating wire 13 is, for example, between 0.1 mm and 5 mm, preferably between 0.3 mm and 3 mm.

[0055] The heating wire 13 also includes a wire section 16 that connects the first end 14 and the second end 15 of the heating wire together.

[0056] according to Figures 4 to 6 In the first example shown, the first end 14 and the second end 15 are each connected to a line segment 16. Each line segment 16 extends along the blade 9, parallel to the elongation axis Y, between the first end 10a and the second end 10b of the blade 9. The line segments 16 are connected together by a bridge 17 opposite to the first electrical connection end 14 and the second electrical connection end 15.

[0057] exist Figure 7 and Figure 8 In the second example shown, the first end 14 and the second end 15 are connected to the line segment 16. The line segment 16 may have a meandering shape extending between the leading edge 11a and the trailing edge 11b. This embodiment is particularly suitable when the fan blades 6, 7 need to be heated over the entire outer surface 12, i.e., when the fan blades 6, 7 need to be heated over both the pressure surface 11i and the suction surface 11e from the leading edge 11a to the trailing edge 11b. To further optimize heating, in this example, the heating wire 12 is fitted with the aforementioned electrical insulation layer 8.

[0058] The heating wire 13 is connected to the power supply device 20. The power supply device 20 typically includes a power source 21 connected to the heating wire 13. The power source has an input terminal 21a connected to a first electrical connection terminal 14 of the heating wire 13 and an output terminal 21b connected to a second electrical connection terminal 15 of the heating wire 13.

[0059] For example, the power source 21 is a generator. The power source 21 is capable of delivering voltage that enables the regulation of the heating power of each fan blade 6, 7, and this voltage is, for example, between 20V and 100V.

[0060] The series and parallel arrangement of fan blades 6 and 7 can achieve compatibility with the power supply voltage, which is, for example, between 500V and 1000V, preferably 800V.

[0061] The maximum power of the heating wire 13 is between 500W and 1000W, preferably between 600W and 800W.

[0062] When the temperature of the cold air stream is between -120°C and 20°C, the heating wire 13 can achieve a temperature of 5°C.

[0063] As required, fan blades 6 and 7 may include multiple heating wires 12, which may be electrically connected in parallel or series. The turbine 1 may also include several fan blades 6 and 7 with heating wires 12, which may be connected to the same power supply device 20. Now, reference will be made to... Figure 9 Describe the methods used to manufacture fan blades 6 and 7.

[0064] Fan blades 6 and 7 are manufactured using additive manufacturing. The additive manufacturing method can be a powder bed melting method. The powder bed melting method can be a selective laser sintering (SLS), a selective laser melting (SLM), or an electron beam melting (EBM) method. According to another example, the method can be a laser metal deposition method, also known as LMD.

[0065] The manufacturing method includes the following steps: (a) Depositing a layer on a substrate comprising a first powder of a first metallic material and a second powder of a second metallic material. (b) Selectively melting the first powder and the second powder, and (c) Repeat steps (a) and (b) until fan blades 6 and 7 are obtained.

[0066] In step (a), each deposited layer includes a first powder and a second powder, the first powder and the second powder respectively containing a first metal material of blade 9 and a second metal material of heating wire 13.

[0067] For example, the thickness of each layer is between 20 μm and 60 μm.

[0068] The first powder and the second powder are deposited from the first metal powder reservoir 106 and the second metal powder reservoir 108, respectively.

[0069] During step (b), after each layer has been deposited, each powder is selectively melted to simultaneously and collectively form blade 9 and heating line 13.

[0070] Melting can be achieved using lasers or electron beams. The laser power ranges from 200W to 1000W, and the laser speed ranges from 500mm / s to 2000mm / s.

[0071] The method may include the following preparatory steps (i): (i) Provide 3D models of fan blades 6 and 7.

[0072] Then, the deposition step (a) and melting step (b) are performed based on the spatial coordinates of the model obtained in step (i).

[0073] Repeat steps (a) and (b) until fan blades 6 and 7 are obtained.

[0074] In the case where the heating wire 13 includes an electrically insulating layer 18, in step (a), the layer includes a third powder containing ceramic material.

[0075] In step (b), the third powder is not melted by laser or electron beam. This maintains the electrical insulation properties of the electrical insulating layer 18.

[0076] In, for example Figure 10 The method is implemented in the additive manufacturing apparatus 100 shown.

[0077] The device 100 includes a support 102 for manufacturing the fan blades 6, 7. For example, the support 102 may be metal. The support 102 may be fixed or may move in a translational and / or rotational manner.

[0078] The device 100 also includes a container 104, which includes a first powder container 106 and a second powder container 108, the first powder container 106 and the second powder container 108 respectively containing a first powder of a first metal material and a second powder of a second metal material. The tray 104 can be translated as indicated by the arrow.

[0079] The apparatus 100 also includes a melting device 110, such as a laser. The melting device 110 can also be translated.

Claims

1. A fan blade (6, 7) for an aircraft turbine (1), said fan blade (6, 7) comprising: - A blade (9) having a pressure surface (11i) and a suction surface (11e) connected by a leading edge (11a) and a trailing edge (11b), the blade (9) comprising a first metallic material, - At least one heating wire (13) extending along the blade (9), the heating wire (13) comprising at least one conductor (17) containing a second metallic material. The characteristic is that the heating wire (13) is integrated into the blade (9) and forms an integral assembly with the blade (9). The heating wire (13) has a first electrical connection end and a second electrical connection end (14, 15) intended to be connected to a power source (21).

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

3. The fan blade according to any one of the preceding claims, characterized in that, The diameter of the heating wire (13) is between 0.1 mm and 5 mm, preferably between 0.3 mm and 3 mm.

4. The fan blade according to any one of the preceding claims, characterized in that, The heating wire (13) is separated from the leading edge (11a) by a distance between 0.1 cm and 5 cm, preferably between 0.5 cm and 2 cm.

5. The fan blade according to any one of the preceding claims, characterized in that, The heating wire (13) also includes an electrically insulating layer (18) arranged around the conductor (17).

6. The fan blade according to the preceding claim, characterized in that, The electrical insulating layer (18) comprises a ceramic material, preferably alumina.

7. The fan blade according to any one of claims 5 or 6, characterized in that, The thickness of the electrical insulation layer (18) is between 0.1 mm and 1 mm, preferably between 0.1 mm and 0.5 mm.

8. A method for additive manufacturing of fan blades (6, 7), said fan blades being the fan blades according to any one of the preceding claims, characterized in that, The method includes the following steps: (a) Depositing a layer comprising a first powder of the first metallic material and a second powder of the second metallic material on the support (102), (b) Selectively melting the first powder and the second powder, and (c) Repeat steps (a) and (b) until the fan blades (6, 7) are obtained.

9. The method according to the preceding claim, characterized in that, In step (a), the layer further includes a third powder comprising ceramic material, and step (b) involves selectively melting the first powder and the second powder.

Images