Part for an aircraft turbine engine

Abstract

The invention relates to a part (9) for an aircraft turbine engine, the part (9) comprising: - a body (10) having a surface (10a) intended to be swept by an airflow, and - a multilayer coating (11) arranged on the surface (10a) of the body (10), characterized in that the coating (11) comprises: - a first electrically insulating layer (12), - a second layer (13) arranged on the first layer (12), the second layer (13) comprising an electrically conductive circuit, and - a third layer (14) arranged on the second layer (13) and comprising a polymeric matrix and piezoelectric fillers, the piezoelectric fillers being deformable under the effect of an electric current transmitted by the second layer (13).

Description

[0001] DESCRIPTION

[0002] TITLE: PART FOR AN AIRCRAFT TURBOMACHINE

[0003] Technical field of the invention

[0004] The invention relates to the field of parts for aircraft turbomachinery.

[0005] The invention relates in particular to the field of parts presenting a risk of ice or frost formation.

[0006] Technical background

[0007] The state of the art is illustrated by document EP-A1-2433868.

[0008] An aircraft turbomachine typically extends along and around a longitudinal axis. It comprises a gas generator which typically includes, 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.

[0009] 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, on the other hand, is connected to the rotor of the high-pressure turbine via a high-pressure shaft.

[0010] The turbomachine further includes a fan located upstream of the gas generator. The fan comprises a rotor driven in rotation about the longitudinal axis by a fan shaft connected to the low-pressure shaft. The fan rotor includes blades evenly distributed around the longitudinal axis and free to rotate about this longitudinal axis.

[0011] The fan can be either shrouded or unshrouded. In the latter case, the fan blades are not enclosed by a casing. The fan draws in an airflow that splits downstream into a primary airflow and a secondary airflow. The secondary airflow flows in an annular secondary channel, and the primary airflow flows in an annular primary channel surrounded by the secondary channel. The secondary airflow is responsible for the majority of the turbomachine's thrust. The primary airflow is compressed in the compressors and then mixed with fuel in the combustion chamber. The gases produced by combustion then power the turbines, driving the low-pressure shaft and, consequently, the low-pressure compressor.

[0012] Turbomachinery is equipped with components that are susceptible to frost and even ice formation. Indeed, ambient temperatures, which can often reach sub-zero levels, combined with air humidity, create favorable conditions for frost and, ultimately, ice formation. For example, the blades of an unshrouded fan are particularly prone to frost or ice buildup. Ice or frost formation is especially disruptive for the turbomachine, as it can disrupt its equilibrium, creating, for example, an imbalance. Furthermore, there is a risk that ice will penetrate the primary cooling channel and damage internal turbomachine components, such as the compressors, through impact.

[0013] To reduce the risk of ice and / or frost formation, it has been proposed to equip certain parts, such as the turbine blades, with active anti-icing systems. These systems are, for example, heating devices in the form of heating blankets that increase the temperature of the blades to reduce the risk of ice and / or frost formation. While this significantly reduces the risk of ice and / or frost formation, such a solution is not entirely satisfactory. These heating devices are bulky and difficult to integrate into the turbomachine. Furthermore, depending on the geometry of the part to be heated, it is not easy to guarantee uniform heating of the entire part with such a heating device.

[0014] Furthermore, these parts are subject to erosion, which can reduce their lifespan. Therefore, there is a need for a component for an aircraft turbomachine that is less prone to frost and / or ice formation and erosion, while also being easily integrated into the turbomachine.

[0015] Summary of the invention

[0016] To this end, the invention proposes a part for an aircraft turbomachine, the part comprising:

[0017] - a body with a surface designed to be swept by an airflow, and

[0018] - a multi-layered coating arranged on the surface of the body.

[0019] The room is remarkable in that the cladding includes:

[0020] - a first electrically insulating layer,

[0021] - a second layer arranged on top of the first layer, the second layer comprising an electrically conductive circuit, and

[0022] - a third layer arranged on the second layer and comprising a polymer matrix and piezoelectric charges embedded in the polymer matrix, the piezoelectric charges being deformable under the effect of an electric current transmitted by the second layer.

[0023] According to the invention, the part therefore includes a coating which comprises at least three layers.

[0024] The second layer allows an electric current to be transmitted to the first layer. Under the effect of this electric current, the piezoelectric charges of the third layer are deformed.

[0025] The deformation of piezoelectric charges results in the swelling of the third layer and / or the induction of vibrations in this third layer.

[0026] The oscillations of the third layer break up and shatter the ice and / or frost on the surface of the part. Furthermore, the first layer facilitates the bonding and deposition of the second and third layers on the surface of the part. The electrically insulating properties of this first layer prevent short circuits within the part.

[0027] Thanks to such a coating, it is therefore possible to reduce the risk of ice and / or frost forming on the part.

[0028] In addition, such a coating is compact and adapts to all part geometries, especially blades.

[0029] Finally, the third layer comprises a polymer matrix. This polymer matrix protects the part's body from erosion. Thanks to this coating, the part is protected from both erosion and the deposition of frost and / or ice.

[0030] The invention may include one or more of the following features, taken individually or in combination with each other:

[0031] - the polymer matrix comprises a polyurethane,

[0032] - the charges include piezoelectric particles,

[0033] - the third layer has a filler content between 10% and 30%,

[0034] - the first layer comprises a polymer, preferably an epoxy polymer,

[0035] - the first layer has a thickness between 10 µm and 20 µm,

[0036] - the second layer has a thickness of less than 1 pm,

[0037] - the third layer has a thickness between 50 µm and 150 µm,

[0038] - the deformation of the piezoelectric charges causes a deformation of the third layer. The invention also relates to a turbomachine for an aircraft, comprising at least one part according to any one of the preceding characteristics.

[0039] According to an advantageous feature of the turbomachine, the part is a blade.

[0040] Brief description of the figures

[0041] Other 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:

[0042] [Fig.1] Figure 1 is a perspective view of an aircraft turbomachine to which the invention can be applied.

[0043] [Fig.2] Figure 2 is a diagram of a blade to which the invention can be applied,

[0044] [Fig.3] Figure 3 is a diagram of the part according to the invention.

[0045] Detailed description of the invention

[0046] An example of an aircraft turbomachine 1 to which the invention can be applied is shown in Figure 1. The turbomachine 1 is, for example, a turbofan engine.

[0047] Turbomachine 1 extends along a longitudinal axis X. A gas flow F flows into turbomachine 1.

[0048] For the purposes of the present invention, the terms "upstream" and "downstream" are understood relative to the direction of flow of the gas flow F in the turbomachine 1 along the longitudinal axis X.

[0049] The terms "radial", "radially", "longitudinally", "axial", "axially", are understood in relation to the longitudinal axis X of the turbomachine 1. The terms "internal", "internally", "externally", are understood in relation to the distance of the longitudinal axis X along a radial axis from the longitudinal axis X.

[0050] The turbomachine 1 may include, from upstream to downstream, a blower 2 and a gas generator. The turbomachine 1 may further include a rectifier 3 located downstream of the blower 2. The gas generator may include, from upstream to downstream, a low-pressure compressor, a high-pressure compressor, at least one annular combustion chamber, a high-pressure turbine, and a low-pressure turbine.

[0051] Each compressor comprises a compressor rotor, and each turbine comprises a turbine rotor. The compressor rotor of the low-pressure compressor is connected to the turbine rotor of the low-pressure turbine by a low-pressure shaft. Together, they form a low-pressure unit.

[0052] The compressor rotor of the high-pressure compressor is connected to the turbine rotor of the high-pressure turbine by a high-pressure shaft. They form a high-pressure unit.

[0053] The low pressure and high pressure shafts can be centered on the longitudinal X axis and are movable in rotation around the longitudinal X axis. The high pressure shaft is arranged coaxially around the low pressure shaft.

[0054] The blower 2 comprises a disc 4 centered on the longitudinal axis X and blades 5 that rotate about the longitudinal axis X. The disc 4 is annular and centered on the longitudinal axis X. It rotates about the longitudinal axis X. The blades 5 extend radially from the disc 4 and are evenly distributed around the longitudinal axis X. They are driven in rotation about the longitudinal axis X.

[0055] Referring to the example in Figure 1, the fan 2 is preferably of the unducted type, also known as an "open rotor." Unlike ducted fans, the fan 2 is not enclosed by a fan casing surrounding its blades 5. The unducted fan turbomachine 1 is preferably a single unducted fan, also known as an "unducted single fan." Unlike contra-rotating open rotor turbomachines, the fan 2 comprises only a single annular row of blades 5 that rotate about the longitudinal axis X. This type of configuration significantly reduces the mass of the turbomachine 1.

[0056] The stator 3 comprises fixed blades 6 rotating about the longitudinal axis X. The blades 6 are evenly distributed around the longitudinal axis X. They may, for example, have variable pitch. The blades 6 are thus free to rotate about their axis of extension Y, which extends radially with respect to the longitudinal axis X of the turbomachine 1. These blades 6 are also known by the English acronym OGV for "outlet guided vanes". The blades 6 of the stator 3 are supported by an annular outer casing 7 centered on the longitudinal axis X. The outer casing 7 is located specifically around the gas generator.

[0057] The gas flow F passes through the blower 2 and splits into a primary air flow F1 through an annular primary stream and a secondary air flow F2 through an annular secondary stream v2 that surrounds the primary stream. The primary stream extends into the gas generator.

[0058] The primary airflow F1 passes through the primary duct and flows successively into the low-pressure and high-pressure compressors. The compressed primary airflow F1 then passes through the combustion chamber where it is mixed with fuel. The combustion gases then 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, which drives the rotation of the low-pressure shaft and, consequently, the low-pressure compressor.

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

[0060] With reference to Figure 2, each blade 5, 6 comprises a body, in particular a blade 8 extending between two opposite ends 8a, 8b along an elongation axis Y.

[0061] Blade 8, for example, comprises a metallic material or a composite material. The metallic material is, for example, aluminum or an aluminum alloy. The composite material is, for example, an organic matrix composite. It comprises a polymer matrix and fibers embedded within the matrix.

[0062] The blade 8 has an aerodynamic shape. It comprises a surface swept by the secondary airflow F2. This surface has an intrados face 8i and an extrados face which are connected by a leading edge 8c and a trailing edge 8d. The leading and trailing edges 8c, 8d extend along the aspect ratio axis Y. The leading and trailing edges 8c, 8d are connected by the intrados face 8i and extrados face 8e along a transverse axis perpendicular to the aspect ratio axis Y. When the blade 5,6 is mounted in the turbomachine 1, the aspect ratio axis Y extends radially with respect to the longitudinal axis X of the turbomachine 1.

[0063] With reference to Figure 3, the turbomachine 1 comprises parts 9. These parts 9 are in particular the blades 5 of the blower 2 or the blades 6 of the straightener 3.

[0064] Each part 9 includes a body 10 which has a surface 10a swept by an airflow, in particular the secondary airflow F2. The body 10 is for example the blade 8.

[0065] The secondary airflow F2 has a low temperature, which may be less than or equal to 0°C. Furthermore, the surface 10a of the body 10 may have a film of water. This moisture, combined with the temperature of the secondary airflow F2, promotes the formation of ice and / or frost on the surface 10a of the body 10. The deposition of frost or ice on the body 10 can create an imbalance in the turbomachine 1 and cause it to become unbalanced. Also, frost or ice formed on these parts 9 can enter the gas generator and cause serious damage.

[0066] In addition, parts 9 of the turbomachine 1, in particular the blades 5, 6 are subject to a risk of erosion.

[0067] In order to limit the risk of ice and / or frost formation and to reduce the erosion of these parts 9, each part 9 further includes a coating 11 arranged on the surface 10a of the body 10.

[0068] The coating 11 is multilayered. According to the invention, the coating 11 comprises a first layer 12 arranged on the surface 10a of the body 10, a second layer 13 arranged on the first layer 12, and a third layer 14 arranged on the second layer 13. The second layer 13 is thus sandwiched between the first and second layers 12 and 14. According to the invention, the first layer 12 is electrically insulating. The first layer 12 advantageously has an electrical conductivity greater than or equal to 10 10 ohm.

[0069] The first layer 12 advantageously comprises a polymer. The polymer is preferably an epoxy polymer. In other examples, the polymer is, for instance, polyester or polyurethane.

[0070] Preferably, the first layer 12 has a thickness between 10 pm and 20 pm.

[0071] The first layer 12 facilitates the deposition and adhesion of the second layer 13 on the surface 10a of the body 10.

[0072] According to the invention, the second layer 13 comprises an electrically conductive circuit. The second layer 13 is, for example, a printed circuit board or a layer containing this circuit.

[0073] Preferably, the second layer 13 has a thickness of less than 1 pm.

[0074] The second layer 13 ensures the transfer of an electric current to the third layer 14.

[0075] According to the invention, the third layer 14 comprises a polymer matrix and piezoelectric fillers. Preferably, the polymer matrix comprises a polyurethane. In another example, the polymer matrix comprises a polyester. The matrix of the third layer 14 protects the surface 10a of the body 10 of the part 9 from erosion.

[0076] The piezoelectric fillers are embedded in the polymer matrix. Preferably, the third layer 14 has a piezoelectric filler content of between 10% and 30%. The fillers preferably consist of piezoelectric particles. Examples include barium titanate (BaTiO3), lead zirconate titanate (PZT), or polyvinylidene fluoride (PVDF).

[0077] The piezoelectric charges are deformable under the effect of an electric current transmitted by the second layer 13. The deformation of the piezoelectric charges under the effect of the current allows the third layer 14 to be deformed, for example to generate vibrations or swelling in the third layer 14. These movements have the effect of breaking or detaching the ice and / or frost from the surface 10a of the body 10 of the part 9. Preferably, the third layer 14 has a thickness of between 50 pm and 150 pm.

[0078] The third layer 14 is swept by the secondary airflow F2.

[0079] The coating 11 is advantageously located on the lower surface 8i and / or on the upper surface 8e and / or on the leading edge 8c and / or on the trailing edge 8d of the fan blade 5 of the blower 2 or of the rectifier blade 6 of the rectifier 3. Each part 9 can be connected to a power supply device 15. The power supply device 15 can generate a voltage between 0 V and 800 V.

[0080] The power supply device 15 has a positive terminal 15a and a negative terminal 15b. The positive and negative terminals 15a, 15b are connected to the second layer 13 to supply electrical power to the second layer 13.

[0081] The power supply device 15 generates an electric current in the second layer 13. This electric current is then transferred to the third layer 14. The passage of the electric current through the third layer 14 deforms the piezoelectric charges. This deformation causes the third layer 14 to swell or vibrate, enabling the ice and / or frost to break away from the surface 10a of the body 10 of the part 9.

[0082] In addition, thanks to the first layer 12 which is electrically insulating, it is possible to eliminate the risk of short circuits.

[0083] The coating 11 of the invention thus exhibits both anti-erosion and anti-ice properties.

[0084] A manufacturing process for parts 5, 6, and 9 will now be described. The manufacturing process may include the following steps:

[0085] - provide body 8, 10 of part 5, 6, 9, and

[0086] - deposit the multilayer coating 11 on the surface 10a of the body 8, 10. The step of depositing the coating 11 may include the following steps: - deposit the first layer 12, preferably by spraying, - deposit the second layer 13 on the first layer 12, for example by spraying, by printing or by laser transfer, also known by the English acronym LIFT for "Laser Induced Forward Transfer", and - deposit the third layer 14 on the second layer 13, preferably by spraying.

Claims

DEMANDS 1. Part (5, 6, 9) for an aircraft turbomachine (1), part (5, 6, 9) comprising: - a body (8, 10) having a surface (10a) intended to be swept by an airflow (F2), and - a multilayer coating (11) arranged on the surface (10a) of the body (8, 10), characterized in that the coating (11) comprises: - a first electrically insulating layer (12), - a second layer (13) arranged on top of the first layer (12), the second layer (13) comprising an electrically conductive circuit, and - a third layer (14) arranged on the second layer (13) and comprising a polymeric matrix and piezoelectric charges embedded in the polymeric matrix, the piezoelectric charges being deformable under the effect of an electric current transmitted by the second layer (13).

2. Part according to the preceding claim, characterized in that the polymeric matrix comprises a polyurethane.

3. Part according to any one of the preceding claims, characterized in that the charges comprise piezoelectric particles.

4. Part according to any one of the preceding claims, characterized in that the third layer (14) has a filler content of between 10% and 30%.

5. Part according to any one of the preceding claims, characterized in that the first layer (12) comprises a polymer, preferably an epoxy polymer.

6. Part according to any one of the preceding claims, characterized in that the first layer (12) has a thickness between 10 pm and 20 pm.

7. Part according to any one of the preceding claims, characterized in that the second layer (13) has a thickness of less than 1 pm.

8. Part according to any one of the preceding claims, characterized in that the third layer (14) has a thickness between 50 pm and 150 pm.

9. Part according to any one of the preceding claims, characterized in that the deformation of the piezoelectric charges causes a deformation of the third layer (14).

10. Turbomachine (1) for an aircraft, characterized in that it comprises at least one part (5, 6, 9) according to any one of the preceding claims.

11. Turbomachine according to the preceding claim, characterized in that the part (9) is a blade (5, 6).

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