DAWN FOR AN AIRCRAFT TURBOMACHINE

Abstract

The invention relates to a blade (11, 11') for an aircraft turbomachine comprising: - a body (12) extending along an axis of elongation (X) and comprising an intrados face (12i) and an extrados face (12e) connected by a leading edge (12a) and a trailing edge (12b), characterized in that it comprises at least one reinforcing layer (16) comprising a shear-thickening material. Abbreviated figure: Figure 2

Description

Title of the invention: BLADE FOR AN AIRCRAFT TURBOMACHINE Technical field of the invention

[0001] The invention relates to the technical field of blades for aircraft turbomachines. Technical background

[0002] 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, a low pressure turbine and a gas exhaust nozzle.

[0003] 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.

[0004] The turbomachine further comprises a fan which is located upstream of the gas generator. The fan comprises a rotor comprising a disc centered on the longitudinal axis and which is rotated about the longitudinal axis by a fan shaft. The fan further comprises blades extending radially from the disc.

[0005] The turbomachine may further comprise a rectifier located downstream of the fan and comprising fixed blades, also known by the English acronym OGV for “Outlet Guided Vanes”.

[0006] The blower allows the suction of an air flow dividing into a primary flow and a secondary flow. The primary flow passes through a primary vein of the turbomachine while the secondary flow is directed towards a secondary vein surrounding the primary vein.

[0007] The primary flow is compressed within the compressors. The compressed air is then mixed with a fuel and burned within the combustion chamber. The gases resulting from the combustion pass through the turbines and then escape through the nozzle, the cross-section of which allows the acceleration of these gases to generate propulsion.

[0008] The blades of the turbomachine, such as the fan blades or the fixed blades, make it possible to exert an action on the air flow. For example, the fan blades make it possible to compress the secondary air flow and the fixed blades to straighten this secondary air flow in order to improve the propulsion force generated.

[0009] A blade typically comprises a body or blade which has an aerodynamic shape. The body thus has an intrados face and an extrados face connected by a leading edge and a trailing edge. The body has a metallic material or a composite material.

[0010] In order to reduce fuel consumption and decrease the environmental footprint of turbomachines while maximizing the propulsive efficiency of the turbomachines, it has been proposed to increase the bypass ratio of aircraft turbomachines. The bypass ratio represents the ratio between the mass of secondary flow and the mass of primary flow flowing in the turbomachine.

[0011] In order to increase this bypass ratio, it has been proposed to increase the size of the blades, such as fan blades, in order to increase the mass of secondary flow passing through the turbomachine.

[0012] However, increasing the size of the blades presents many challenges. Indeed, the larger the size of the blades, the more likely they are to experience impacts. For example, it has been found that by doubling the surface area of ​​fan blades, the number of impacts with flying foreign objects, such as birds, is also at least doubled. In addition, the larger the size of the blades, the more their mass increases, which goes against the desired performance gain. Also, it is necessary to ensure easy and low-cost manufacturing of such blades.

[0013] Therefore, there is a need to provide blades for aircraft turbomachines, the dimensions of which can be increased, while ensuring their impact resistance, low mass and easy manufacture. Summary of the invention

[0014] To this end, the invention proposes a blade for an aircraft turbomachine comprising:

[0015] - a body extending along an elongation axis and comprising an intrados face and an extrados face connected by a leading edge and a trailing edge.

[0016] The blade is remarkable in that it comprises at least one reinforcing layer comprising a rheothickening material.

[0017] The reinforcing layer according to the invention makes it possible to reinforce the body of the blade against impacts.

[0018] According to the invention, this reinforcing layer comprises a rheothickening material. Such a material is characterized in particular by a viscosity which increases when the shear rate increases. This material is also called a “dilating” material.

[0019] Such a material, the state of which changes according to the force applied to it, makes it possible to provide good impact resistance.

[0020] Furthermore, such a material has a density lower than the density of metallic materials and thus makes it possible to reinforce the impact resistance of the blade without considerably increasing its mass.

[0021] Thanks to the invention, it is therefore possible to considerably increase the size of the blade while guaranteeing good impact resistance or shock resistance without significantly increasing the mass of this blade.

[0022] Consequently, it is possible to reduce the fuel consumption of the turbomachines in which the blade is integrated and to reduce the environmental footprint of these turbomachines while maximizing their propulsive efficiency without impacting the impact resistance of the blades.

[0023] Furthermore, such a layer can be easily integrated into the blade, which allows easy manufacture of the blade.

[0024] The invention may comprise one or more of the following features, taken in isolation from one another or in combination with one another:

[0025] - the rheothickening material has a density of between 0.1 and 0.65,

[0026] - the rheothickening material has a tensile strength as measured at 20°C between 0.5 and 5 MPa, preferably 1 MPa,

[0027] - the rheothickening material is D3O®,

[0028] - the reinforcing layer is arranged on the intrados face and / or the extrados face and / or the leading edge and / or trailing edge and / or along the leading edge and / or along the trailing edge,

[0029] - the reinforcing layer has a thickness of between 2 mm and 50 mm,

[0030] - the reinforcing layer extends along the elongation axis between a first end and a second end of the blade,

[0031] - the body comprises a metallic material or a composite material,

[0032] - a protective shield arranged on the leading edge and / or the trailing edge, the reinforcement layer being located between the protective shield and the body of the blade,

[0033] - at least one protective layer arranged on the intrados and / or extrados face of the blade body, the reinforcing layer being located between the protective layer and the blade body. Brief description of the figures

[0034] 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:

[0035] [Fig.l] [Fig.l] is a longitudinal sectional view of an example of an aircraft turbomachine;

[0036] [Fig.2] [Fig.2] is a cross-sectional view of a blade according to a first embodiment of the invention;

[0037] [Fig.3] [Fig.3] is a cross-sectional view of a blade according to a second embodiment of the invention. Detailed description of the invention

[0038] An example of an aircraft turbomachine 1 according to the invention is shown in [Fig.l]. The turbomachine 1 extends around and along a longitudinal axis A.

[0039] In the present application, the terms "axial", "axially", "radial" and "radially" are defined with respect to the longitudinal axis A.

[0040] The terms “upstream” and “downstream” are defined in relation to the direction of circulation of the gases in the turbomachine 1 along the longitudinal axis A.

[0041] The terms “internal”, “interior”, “external”, “exterior”, “externally” are defined in relation to the distance from the longitudinal axis A along a radial axis perpendicular to the longitudinal axis A.

[0042] The turbomachine 1 comprises from upstream to downstream in the direction of flow of the gases F along the longitudinal axis A, a fan 2, at least one compressor such as a low pressure compressor 3 and a high pressure compressor 4, a combustion chamber 5, at least one turbine 6 such as a high pressure turbine and a low pressure turbine, and a gas exhaust nozzle.

[0043] The rotor of the low pressure turbine is connected to the fan 2 and to the rotor of the low pressure compressor 3 by a low pressure shaft (not shown). The rotor of the high pressure turbine is connected to the rotor of the high pressure compressor 4 by a high pressure shaft (not shown).

[0044] The turbomachine 1 further comprises a rectifier 10. The rectifier 10 makes it possible to straighten the air flow at the outlet of a rotor located upstream in order to provide maximum thrust at the outlet of the turbomachine 1. In the particular example of [Fig.l], the rectifier 10 is located downstream of the fan 2.

[0045] The blower 2 allows the suction of an air flow F dividing into a primary air flow F1 and a secondary air flow F2. The primary air flow F1 passes through a primary vein of the turbomachine 1 while the secondary air flow F2 is directed towards a secondary vein surrounding the primary vein.

[0046] The primary air flow F1 is compressed within the low-pressure compressor 3 and then the high-pressure compressor 4. The compressed air is then mixed with a fuel and burned within the combustion chamber 5. The gases formed by the combustion pass through the high-pressure turbine and the low-pressure turbine. The gases finally escape through the nozzle, the cross-section of which allows the acceleration of these gases to generate propulsion. The secondary air flow F2 passes through the rectifier 10, which accelerates the circulation speed of the secondary air flow F2 to generate propulsion.

[0047] The fan 2 comprises blades 11 regularly distributed around the longitudinal axis A and movable in rotation around this longitudinal axis A.

[0048] The rectifier 10 also comprises vanes 11' regularly distributed around the longitudinal axis A and generally fixed in rotation around this longitudinal axis A. They are known by the English acronym OGV for “Outlet Guide Vane”.

[0049] In the remainder of the description, the blades 11 of the fan 2 and the blades 11' of the rectifier 10 are referred to interchangeably as "blade".

[0050] Each blade 11, 11' comprises a body or a blade 12. The body 12 extends along an elongation axis X. The elongation axis X of the body 12 extends radially relative to the longitudinal axis A of the turbomachine 1 after mounting the blade 11, 11' on the turbomachine 1.

[0051] As best seen in Figures 2 and 3, the body 12 has an aerodynamic profile. The body 12 thus has an extrados face 12e and an intrados face 12i. The extrados face 12e is connected to the intrados face 12i by a leading edge 12a and a trailing edge 12b. The leading edges 12a and trailing edge 12b extend along the elongation axis X.

[0052] The body 12 also extends longitudinally along the elongation axis X between a first end and a second end opposite the first end.

[0053] According to a first embodiment illustrated in [Fig.2], the body 12 comprises a metallic material. The metallic material of the body 12 is for example aluminum.

[0054] According to this embodiment, the blade 11, 11' may further comprise at least one protective layer 14 arranged on the body 12. The protective layer 14 may be arranged on the intrados face 12i and / or the extrados face 12e of the body 12. The protective layer 14 comprises, for example, a metallic material such as aluminium.

[0055] According to this embodiment, the blade 11, 11' may further comprise a protective shield (not shown) arranged on the leading edge 12a and / or the trailing edge 12b. It advantageously extends along the entire length of the leading edge 12a. The protective shield is advantageously made of a metallic material. The metallic material is, for example, titanium or an alloy such as a steel, for example, a stainless steel or a nickel and cobalt alloy (NiCo), an aluminum, silver, zinc, nickel, copper or a mixture thereof. The protective shield is, according to another example, made of a ceramic material. It is intended to improve the protection of the leading edge 12a against external impacts.

[0056] According to a second embodiment illustrated in [Fig. 3], the body 12 comprises a composite material. The composite material comprises a polymer matrix and a fibrous reinforcement embedded in the matrix. The composite material is for example a organic matrix composite (OMC). The matrix is, for example, a thermoplastic or thermosetting polymer matrix. The thermosetting material is, for example, an epoxy polymer. The fiber reinforcement includes fibers, for example, carbon fibers or glass fibers. The fibers are organized, for example, in the form of a fiber preform.

[0057] According to this second embodiment, the blade 11, 11' may further comprise at least one protective shield 15 arranged on the body 12. The protective shield 15 is advantageously arranged on the leading edge 12a. It advantageously extends along the entire length of the leading edge 12a. The protective shield 15 is advantageously made of metallic material. The metallic material is for example titanium or an alloy such as a steel, for example a stainless steel or a nickel and cobalt alloy (NiCo), an aluminum, silver, zinc, nickel, copper or a mixture thereof. The protective shield 15 is according to another example made of ceramic material. It is intended to improve the protection of the leading edge 12a against external impacts.

[0058] The protective shield 15 has an elongated dihedral shape. The protective shield 15 has a V-shaped or U-shaped cross-section. The protective shield 15 comprises a first lateral fin 15a and a second lateral fin 15b connected to the first lateral fin 15a by a web 15j. The first and second lateral fins 15a, 15b define between them a cavity in which the leading edge 12a is arranged.

[0059] The first lateral fin 15a has a first free longitudinal end and the second lateral fin 15b has a second free longitudinal end which are opposite the core 15j. The free longitudinal ends extend along the body 12. The free longitudinal ends extend respectively on the intrados face 12i and the extrados face 12e of the body 12.

[0060] Alternatively, the protective shield 15 is arranged on the trailing edge 12b. According to yet another alternative not shown, the blade 11, 11' comprises two protective shields 15 arranged respectively on the leading edge 12a and the trailing edge 12b.

[0061] According to the invention, the blade 11, 11' further comprises at least one reinforcing layer 16. The reinforcing layer 16 may be arranged on the body 12 or in the body 12. The reinforcing layer 16 may be located on the leading edge 12a and / or on the trailing edge 12b and / or on the intrados face 12i and / or on the extrados face 12e of the body 12.

[0062] Advantageously, the reinforcing layer 16 has a thickness of between 2 mm and 50 mm. The thickness of the reinforcing layer 16 may for example be greater than or equal to one fifth of the thickness of the body 12.

[0063] The reinforcing layer 16 can be glued, molded, welded onto or into the body 12.

[0064] The reinforcing layer 16 may have an elongated shape along the elongation axis Y of the body 12. It may, for example, extend from the first end to the second end of the body 12.

[0065] The reinforcing layer 16 may be of any shape adapted to the blade 11, 11'. It may, for example, have a plane or revolution shape. It may have a circular, elliptical or polygonal cross-section.

[0066] With reference to [Fig.2] illustrating the first embodiment in which the body 12 comprises a metallic material, the blade 11, 11' comprises a first reinforcing layer 16a located on at least a portion of the extrados face 12e and / or a second reinforcing layer 16b located on at least a portion of the intrados face 12i and / or a third reinforcing layer 16c located on the leading edge 12a and / or a fourth reinforcing layer 16d located on the trailing edge 12b.

[0067] According to this embodiment, the third and fourth reinforcement layers 16c, 16d have a shape of revolution. They have, for example, a circular section. They are, for example, located in a cavity extending along the elongation axis X in the body 12.

[0068] According to this embodiment, the reinforcing layer 16, and in particular the first and second reinforcing layers 16a, 16b are located between the body 12 and the protective layer 14. According to an alternative, the first and second reinforcing layers 16a, 16b are located in a cavity provided in the body 12.

[0069] With reference to [Fig. 3] illustrating the second embodiment in which the body 12 comprises a composite material, the reinforcing layer 16 is located on the leading edge 12a. In particular, the reinforcing layer 16 is located between the protective shield 15 and the body 12. According to this example, the reinforcing layer 16 may comprise an elongated dihedral shape. The reinforcing layer 16 has a V-shaped or U-shaped cross-section. The reinforcing layer 16 comprises a first lateral fin 17a and a second lateral fin 17b connected to the first lateral fin 17a by a core 17c. The first and second lateral fins 17a, 17b define between them a cavity in which the leading edge 12a is arranged.

[0070] The or each reinforcing layer 16 comprises a rheothickening material. In known manner, rheothickening materials are part of the category of non-Newtonian fluids. Rheothickening materials are characterized in particular by a viscosity which increases when the shear rate increases. Rheothickening materials are also called “dilating” materials.

[0071] The rheothickening material can be characterized by its critical shear rate. The term “critical shear rate” means any shear rate from which the viscosity value (measured in Pa.s) of the rheothickening material increases by more than one order of magnitude (i.e. by at least one factor 10 or one logarithmic unit). This corresponds to a sudden “thickening” of the suspension.

[0072] Advantageously, the rheothickening material has a density of between 0.1 and 0.65.

[0073] Advantageously, the rheothickening material has a tensile strength as measured at 20°C of between 0.5 and 5 MPa, preferably 1 MPa.

[0074] Advantageously, the rheothickening material is the D3O® material marketed by the company D3O.

[0075] The reinforcing layer 16 according to the invention has remarkable impact resistance or shock resistance properties thanks to the rheothickening material used. Also, the mass of such a reinforcing layer 16 is not very significant given the density of this rheothickening material. This makes it possible to improve the impact resistance of the blade 11, 11' without significantly increasing the mass of the blade 11, 11'.

Claims

Claims

1. Blade (11, 11') for an aircraft turbomachine (1) comprising: - a body (12) extending along an elongation axis (X) and comprising an intrados face (12i) and an extrados face (12e) connected by a leading edge (12a) and a trailing edge (12b), characterized in that it comprises at least one reinforcing layer (16, 16a, 16b, 16c, 16d) comprising a rheothickening material.

2. Blade according to the preceding claim, characterized in that the rheothickening material has a density of between 0.1 and 0.

65.

3. Blade according to one of claims 1 or 2, characterized in that the rheothickening material has a tensile strength as measured at 20°C of between 0.5 and 5 MPa, preferably 1 MPa.

4. Blade according to any one of the preceding claims, characterized in that the rheothickening material is D3O®.

5. Blade according to any one of the preceding claims, characterized in that the reinforcing layer (16, 16a, 16b, 16c, 16d) is arranged on the intrados face (12i) and / or the extrados face (12e) and / or the leading edge (12a) and / or the trailing edge (12b) and / or along the leading edge (12a) and / or along the trailing edge (12b).

6. Blade according to any one of the preceding claims, characterized in that the reinforcing layer (16, 16a, 16b, 16c, 16d) has a thickness of between 2 mm and 50 mm.

7. Blade according to any one of the preceding claims, characterized in that the reinforcing layer (16, 16a, 16b, 16c, 16d) extends along the axis of elongation (X) between a first end and a second end of the blade (11, 11').

8. A blade according to any preceding claim, characterized in that the body (12) comprises a metallic material or a composite material.

9. Blade according to any one of the preceding claims, characterized in that it further comprises a protective shield (15) arranged on the leading edge (12a) and / or the trailing edge (12b), the reinforcing layer (16) being located between the protective shield (15) and the body (12) of the blade (11, 11').

10. Blade according to any one of the preceding claims, characterized in that it further comprises at least one layer of protection (14) arranged on the intrados (12i) and / or extrados (12e) face of the body (12) of the blade (11, 11'), the reinforcing layer (16a, 16b) being located between the protection layer (14) and the body (12) of the blade (11, H').

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