Support device for at least one stator blade of an aircraft turbomachine and its method of use

Abstract

A support device (1) for a stator blade (22) of an aircraft turbomachine with longitudinal axis (X) comprising an external wall (21) from which the stator blade (22) projects, the support device (1) comprising: - a housing (2) configured to radially receive a mounting foot (23) of the stator blade (22); - an upstream support foot (5) and a downstream support foot (6) connected respectively to an upstream end (3) and a downstream end (4) of the housing (2) and configured to be mounted on the external wall (21) of the aircraft turbomachine; the downstream support foot (6) comprising a cavity in which is mounted a shock indicator (10) configured to change its visual appearance irreversibly in the event of deformation of a contour (9) of predetermined shape of the cavity, so as to visually detect an impact exerted on the stator blade (22). Figure from the summary: Figure 2

Description

Title of the invention: Support device for at least one stator blade of an aircraft turbomachine and method of its use. Technical field

[0001] The present invention relates to an aircraft turbomachine and more specifically to a support device for at least one stator blade and its method of use.

[0002] Civil aviation has been actively contributing to the fight against climate change for several years now. Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain less energy-intensive and more environmentally friendly aeronautical components and products, whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0003] This sustained research and development work focuses in particular on new generations of aircraft turbomachinery known as "unfaired" in that they are free of a nacelle surrounding the aircraft turbomachine. An unfaired turbomachine typically comprises, upstream, a fan configured to guide an airflow in a defined air stream from upstream to downstream by one or more compressors, a combustion chamber, and one or more turbines. The absence of a fairing surrounds the fan, allowing for a very large fan diameter exceeding 4 meters. The mass of the aircraft turbomachine is advantageously reduced, and the thrust improved, resulting in a 20% reduction in fuel consumption compared to the latest generations of aircraft turbomachinery.

[0004] In practice, a stator is mounted externally on the aircraft turbomachine, downstream of the fan, to straighten the airflow not admitted into the air stream and thus enhance thrust. Like the fan, the stator is not enclosed in a fairing. Such a stator comprises a plurality of stator blades, each consisting of a radial blade and a mounting foot connected by a platform. The mounting foot of each stator blade is mounted in a housing that is attached to the outer casing of the compressor(s). In the case of variable-pitch stator blades, the mounting foot is pivotally mounted radially within the housing to adjust the angle of attack of the stator blades during flight.

[0005] Because it is not enclosed, such a stator is more exposed to the risk of impact from a solid object, such as a bird, which could in the long term damage the parts of the aircraft turbomachine, in particular deforming the compressor housing and / or outer casing. This sometimes necessitates replacing the damaged parts to preserve the performance of the aircraft turbomachine and extend its service life.

[0006] In addition to maintenance costs and ground downtime, another difficulty lies in detecting damage to parts. This requires operators to perform ground inspections that are costly and time-consuming, and in some cases, insufficient. Indeed, some damage may not be visible to the naked eye, preventing its detection and the replacement of the affected parts, with the risk of ultimately reducing the performance and lifespan of the aircraft turbomachine.

[0007] The invention thus aims to detect in a simple and reliable manner damage following an impact of a solid body on the uncased stator of an aircraft turbomachine. PRESENTATION OF THE INVENTION

[0008] The invention relates to a support device for at least one stator blade of an aircraft turbomachine, the aircraft turbomachine extending along a longitudinal axis oriented upstream to downstream and comprising an external wall from which the stator blade projects along a radial axis, the support device comprising: • At least one housing configured to radially receive a stator blade mounting foot, • An upstream support foot and a downstream support foot connected respectively to an upstream end and a downstream end of the housing and configured to be mounted on the external wall of the aircraft turbomachine.

[0009] The invention is remarkable in that the downstream support foot comprises at least one cavity in which at least one shock indicator is mounted, the cavity having a contour of predetermined shape, the shock indicator being configured to change its visual appearance irreversibly in the event of deformation of the contour of the cavity, so as to visually detect an impact exerted on the stator blade.

[0010] The shock indicator of the support device according to the invention advantageously allows for simple, early, and reliable detection of an impact, typically caused by a solid body, such as a bird. Thanks to the shock indicator, a simple visual check of the latter indicates whether an impact has occurred, without requiring a time-consuming and laborious examination of the parts of the aircraft turbomachine. Furthermore, the shock indicator reveals impacts invisible to the naked eye. By ensuring accurate detection, the shock indicator allows for the early and reliable determination of whether replacement of a component of the rectifier and / or the outer wall is necessary to maintain the performance of the aircraft turbomachine.

[0011] According to one aspect of the invention, under nominal conditions, the shock indicator is in contact with the contour of the cavity. This facilitates the transmission of the forces generated by the impact to the shock indicator. The shock indicator thus mounted in the cavity limits its size and mass.

[0012] According to one aspect of the invention, the shock indicator is passive, advantageously requiring no manual or electronic control.

[0013] According to one aspect of the invention, the shock indicator comprises a material adapted to break or deform plastically under compression in the event of deformation of the cavity contour. The shock indicator thus exhibits lower elasticity and / or ductility than the material constituting the body, which is more easily damaged and allows for easy detection of even a moderate impact.

[0014] According to one aspect of the invention, the cavity of the downstream support foot is through-hole. This promotes deformation of the contour under the effect of an impact.

[0015] According to one aspect of the invention, the cavity contour has a decreasing transverse width from upstream to downstream, preferably teardrop-shaped with a wide upstream end and a narrow downstream end aligned transversely with respect to the longitudinal axis. This promotes deformation of the contour under the effect of an impact, typically a bird striking the stator blade from upstream.

[0016] According to one aspect of the invention, the downstream support foot has a groove extending in the longitudinal direction of the cavity. This promotes deformation of the contour under the effect of an impact.

[0017] The invention also relates to an aircraft turbomachine extending along a longitudinal axis oriented from upstream to downstream and comprising: • An external wall, preferably in the form of an external compressor casing, • An unfaired rectifier comprising at least one stator blade projecting outwards from the outer wall along a radial axis, • At least one support device (1) as described above, in which the upstream support foot and the downstream support foot are mounted on the outer wall, the stator blade comprising a mounting foot mounted radially in the housing of the support device.

[0018] Preferably, the aircraft turbomachine is of the unfaired type. The stator blades of the rectifier are not protected by a fairing and are more exposed to the risk of impact from external foreign objects such as birds.

[0019] The invention also relates to a method of using a support device as described above, in which the shock indicator changes its visual appearance irreversibly upon deformation of the cavity contour, so as to visually detect an impact exerted on the stator blade. Such a method advantageously allows for simple, reliable, and rapid detection of an impact and signals a possible need for replacement of a turbomachine component.

[0020] The invention also relates to a method for manufacturing a support device as described above, comprising: • A cavity formation stage in the downstream support foot, • A step of filling the cavity with a malleable material, • A hardening step of the malleable material, in order to form the shock indicator.

[0021] Such an assembly is advantageously simple to implement and limits the bulk and mass associated with integrating the shock indicator into the support device. PRESENTATION OF THE FIGURES

[0022] The invention will be better understood upon reading the following description, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0023] Fig. 1 is a schematic perspective representation of an aircraft turbomachine according to one embodiment of the invention.

[0024] The [Fig.2] is a schematic representation in longitudinal half-section of the support device under nominal conditions according to one embodiment of the invention.

[0025] The [Fig.3] is a schematic representation in close perspective of the downstream support foot of the support device of the [Fig.2] having a nominal visual appearance.

[0026] The [Fig.4] is a schematic representation in longitudinal half-section of the support device of the [Fig.2] during an impact exerted on the stator blade.

[0027] Fig. 5 is a schematic close-up perspective representation of the downstream support foot of Fig. 4 having a visually damaged appearance according to a first embodiment of the invention.

[0028] The [Fig.6] is a schematic representation in close perspective of the downstream support foot of the [Fig.4] having a visually damaged appearance according to a second embodiment of the invention.

[0029] Fig. 7 is a schematic close-up perspective representation of a manufacturing process for the downstream support foot according to an embodiment of the invention.

[0030] It should be noted that the figures set out the invention in detail to implement the invention, said figures being of course able to serve to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0031] With reference to [Fig. 1], the invention relates to an aircraft turbomachine 20 extending along a longitudinal axis X oriented from upstream to downstream. The aircraft turbomachine 20 conventionally comprises, at its upstream end, a fan 27 configured to guide an airflow in an air stream 28 defined from upstream to downstream by one or more compressors, a combustion chamber, and one or more turbines. The fan 27 is of the unshod type and preferably has a diameter greater than 4 m. The aircraft turbomachine 20 is preferably in the form of a turboprop engine in which the fan 27 is driven by the turbine(s) via a reduction gear.

[0032] With reference to Figures 1 and 2, the aircraft turbomachine 20 also includes an unshod-type stator 29 extending radially outward from the air stream 28, downstream of the fan 27. The unshod stator 29 allows the airflow not admitted into the air stream 28 to be straightened and thus enhances thrust. The stator 29 comprises a plurality of stator blades 22 projecting outward from an external wall 21 of the aircraft turbomachine 20, preferably along a radial axis Y. Each stator blade 22 comprises a radial blade 25 and a mounting foot 23 connected by a platform 24.

[0033] The aircraft turbomachine 20 is preferably of the unfaired type, that is to say, it is free of a nacelle surrounding the aircraft turbomachine 20.

[0034] With reference to [Fig.2], the invention relates to a support device 1 for one or more stator blades 22 of the unfaired rectifier 29 of the aircraft turbomachine 20, comprising: • One or more housings 2, each configured to radially receive a mounting foot 23 for a stator blade 22, • An upstream support leg 5 and a downstream support leg 6 connected respectively to an upstream end 3 and a downstream end 4 of the(s) housings 2 and configured to be mounted on the external wall 21 of the aircraft turbomachine 20, • The downstream support foot 6 includes a cavity in which a shock indicator 10 is mounted, the cavity having a contour 9 of predetermined shape, the shock indicator 10 being configured to change its visual appearance irreversibly in the event of deformation of the contour 9 of the cavity 8 so as to visually detect an impact A exerted on the stator blade 22 (see [Fig.4]).

[0035] The shock indicator 10 of the support device 1 according to the invention advantageously allows for simple, early and reliable detection of an impact A. As illustrated in [Fig. 4], such an impact A is typically caused by a solid body, such as a bird, striking the stator 29, particularly at the leading edge of the stator blades 22 in a substantially longitudinal direction X. Due to its unshrouded design, the stator 29 is more exposed to such a risk of impact A, which can damage certain parts of the aircraft turbomachine 20, in particular the stator 29 and / or the outer wall 21.

[0036] Thanks to the shock indicator 10, a simple visual inspection of the latter indicates the occurrence of an impact A, without requiring a time-consuming and laborious examination of the parts of the aircraft turbomachine 20. Furthermore, the shock indicator 10 makes it possible to detect an impact A invisible to the naked eye that might otherwise have gone unnoticed. By ensuring accurate detection, the shock indicator 10 makes it possible to determine early and reliably whether the replacement of a part of the rectifier 29 and / or the outer wall 21 is necessary to maintain the performance of the aircraft turbomachine 20.

[0037] According to a preferred aspect, the support device 1 is in the form of a peripheral piece with longitudinal axis X comprising a housing 2 for each stator blade 22 of the rectifier 29. According to another preferred aspect, the support device 1 is in the form of one or more angular sectors each comprising one or more housings 2 and extending partially peripherally or peripherally around the longitudinal axis X.

[0038] According to a preferred aspect, the outer wall 21 to which the support device 1 is fixed is in the form of the outer wall of the air duct 28, and preferably the outer casing of one or more compressors mounted in the air duct 28. In the example of [Fig. 2], the upstream support foot 5 is fixed to the outer casing 21A of an upstream compressor and the downstream support foot 6 is fixed to the outer casing 21B of a downstream compressor of the aircraft turbomachine 20. One or more fasteners secure the support feet 5, 6 to the outer wall 21, such as screws, rivets, or bolts. The outer wall 21 may be typically made of composite material based on woven carbon fibers wrapped with thermosetting polymer resin.

[0039] According to a preferred aspect illustrated in [Fig. 2], the mounting foot 23 of the stator blade 22 is pivotally mounted about the radial axis Y in the housing 2. In other words, the stator blades 22 of the rectifier 29 are of the variable pitch type, which allows their angle of attack to be changed according to flight conditions. It should be noted that the stator blades 22, unlike rotor blades, are not mounted to rotate freely about the longitudinal axis X. The only degree of freedom of the rotor blade 22 is rotation about the radial axis Y. Alternatively, the mounting foot 23 of the stator blade 22 is fixedly mounted in the housing 2.

[0040] As illustrated in [Fig.2], the support device 1 preferably defines a volume L delimited upstream by the upstream support foot 5 and downstream by the downstream support foot 6. The volume L extends radially between the outer wall 21 and the housing 2 and allows for the housing of a control device (not shown) for the pitch angle of one or more stator blades 22, namely their pivot angle about the radial axis Y in the housing 2.

[0041] With reference to [Fig. 3], the downstream support foot 6 of the support device 1 comprises a body 7 connected upstream to the downstream end 4 of the housing 2 and downstream to the outer wall 21. Preferably, the body 7 is a single piece, and in this example, a single piece with the housing 2. In this example, the body 7 is fixed to the outer wall 21, for example, by screws, rivets, or bolts. The body 7 is preferably made of titanium. Such a body 7 exhibits good mechanical strength without increasing the mass of the aircraft turbomachine 20.

[0042] As illustrated in [Fig.7], the cavity 8 is formed in the body 7 of the downstream support foot 6, preferably by machining the body 7. The body 7 thus comprises a first branch 14 and a second branch 15 extending on either side of the cavity 8. The contour 9 of the cavity 8 is formed by the walls of the body 7 delimiting the cavity 8.

[0043] As illustrated in [Fig. 3], the shock indicator 10 extends into the cavity 8 and, under nominal conditions, i.e., before the occurrence of an impact A, has a first visual appearance OK. As illustrated in [Fig. 4], during an impact A exerted on the stator blade 22, the forces transmitted to the support device 1 pass through the body 7, which deforms the contour 9 and gives the shock indicator 10 a second visual appearance POK, as illustrated in Figures 5 and 6. Mounting the shock indicator 10 in the cavity 8 facilitates the transmission of forces to the shock indicator 10 without increasing the mass or size of the support device 1.

[0044] According to a preferred aspect illustrated in [Fig. 3], under nominal conditions, the shock indicator 10 is in contact with the contour 9 of the cavity 8, preferably with the entire circumference of the contour 9, i.e., fills the cavity 8. This facilitates the transmission of forces to the shock indicator 10. Preferably also, the cavity 8 is through-hole, i.e., it communicates with the volume L. This facilitates the deformation of the contour 9 and, consequently, the transmission of forces to the shock indicator 10.

[0045] According to a preferred aspect illustrated in [Fig. 7], the cavity 8 extends longitudinally and comprises a wide end 12 positioned upstream and a narrow end 13 positioned downstream. Preferably, the contour 9 of the cavity 8 has a transverse width with respect to the longitudinal axis X that decreases from the wide end 12 to the narrow end 13. The contour 9 typically has a teardrop or droplet shape in this example. Such a cavity 8 promotes the deformation of the contour 9 by bringing the wide end 12 closer to the narrow end 13 during an impact A exerted from upstream to downstream on the stator blade 22, as illustrated in [Fig. 4]. Other contour shapes 9 with a wide end 12 upstream and a narrow end 13 downstream, such as an ovoid, a pear, or a triangle, are alternatively suitable.

[0046] According to a preferred aspect illustrated in [Fig. 3], the cavity 8 is formed in the body 7 closer to the downstream end 4 of the housing 2 than to the outer wall 21. In this example, the cavity 8 is juxtaposed to the downstream end 4 of the housing 2 for better transmission of the impact forces A. Preferably also, the cavity 8 extends in a substantially longitudinal portion of the body 7 in a direction substantially identical to that of the solid object striking the stator blade 22. According to another preferred aspect, the cavity 8 extends over more than 20% of the length of the body 7, and preferably over less than 70%, to be easily visible to the operator and to ensure sufficient mechanical strength.

[0047] According to a preferred aspect illustrated in [Fig. 3], the body 7 also includes a groove 11 extending along the longitudinal axis of the cavity 8. The arms 14, 15 extend on either side of the groove 11 and the cavity 8. The groove 11 advantageously reinforces the deformation of the contour 9 in the event of an impact. In this example, the cavity 8 and the groove 11 extend together along the entire length of the body 7.

[0048] With reference to Figures 3 to 6, the shock indicator 10 is adapted to change its visual appearance from a first visual appearance OK ([Fig. 3]) under nominal conditions to a second visual appearance POK (Figures 5 and 6) in the event of deformation D of the contour 9, generated by an impact A exerted on the stator blade 22 ([Fig. 4]). The second visual appearance POK is irreversible and allows for simple and reliable confirmation of the occurrence of the impact A. According to a preferred design, the shock indicator 10 is of the type passive, meaning that it requires no manual or electrical control in a simple and practical way.

[0049] According to a preferred aspect illustrated in Figures 5 and 6, the impact indicator 10 comprises a material adapted to break ([Fig. 5]) or deform plastically ([Fig. 6]) under the effect of impact A, giving it its second visual appearance POK. The impact indicator 10 typically has lower elasticity and / or breaking strength than the body 7 and / or the outer wall 21. Thus, damage to the impact indicator 10 under the effect of an impact A will be more visible than on the body 7 and / or the outer wall 21. In the case of a moderate impact A, the impact indicator 10 will advantageously be in the second visual appearance POK, indicating to the operator that the body 7 and / or the outer wall 21 are likely to be damaged even if this is not visible, for example, elastic deformation or internal damage.

[0050] In the example of [Fig. 5], the material of the impact indicator 10 is designed to break and, in the second visual aspect POK, has one or more cracks or even breaks. In the first visual aspect OK, the impact indicator 10 is free of cracks. The impact indicator 10 is typically in the form of an abradable aircraft material, in particular a composite material comprising a set of glass elements embedded in an epoxy polymer. The glass promotes breakage under the effect of an impact A. The glass elements, such as beads, are preferably hollow to limit the mass.

[0051] In the example of [Fig. 6], the material of the shock indicator 10 is adapted to deform plastically, typically to compress irreversibly, and has, in the second visual aspect POK, a compressed state relative to the first visual aspect OK. In this example, the shock indicator 10 in the second visual aspect POK is no longer in contact with the entire contour 9 of the cavity 8, in particular the wide end 12. The shock indicator 10 is typically in the form of a hardened polyurethane foam, of low mass and adapted to compress without returning to its original shape.

[0052] As illustrated in [Fig. 7], the shock indicator 10 is typically formed by filling the cavity 8 with a malleable material M, which is then hardened. In the example of [Fig. 5], the malleable material M is in the form of an epoxy polymer paste loaded with glass elements, which is deposited in the cavity 8. It hardens in ambient air or by heating. In the example of [Fig. 6], the malleable material M is in the form of a polyurethane foam, which is sprayed into the cavity 8. The polyurethane foam hardens upon contact with ambient air.

[0053] With reference to figures 1 to 3, the method of using the support device 1 according to the invention is typically implemented during the flight of the aircraft turbomachine 20. Under nominal conditions, the shock indicator 10 has the first OK visual appearance, namely, in this example, is in contact with the entire contour 9 of the cavity 8 and is free from cracks.

[0054] As illustrated in [Fig. 4], during an impact A exerted on the stator blade 22, the shock indicator 10 is irreversibly modified and exhibits the second visual appearance POK, typically passively. In the example of [Fig. 5], the second visual appearance POK shows cracks. In the example of [Fig. 6], the second visual appearance POK is compressed and is no longer in contact with the wide end 12. The impact A is typically caused by a solid body such as a bird striking the stator blade 22 substantially longitudinally from upstream to downstream. The shock experienced by the stator blade 22 is transmitted to the support device 1, which generates a deformation D of the contour 9 of the cavity 8, elastic for a moderate impact and plastic for a more significant impact.

[0055] The second visual aspect POK of the shock indicator 10 advantageously informs an operator in a simple, reliable, and rapid manner that an impact A has occurred and of any possible damage to one or more parts of the aircraft turbomachine, in some cases imperceptible to the naked eye. This makes it possible to determine whether a replacement is necessary.

Claims

Demands

1. A support device (1) for at least one stator blade (22) of an aircraft turbomachine (20), the aircraft turbomachine (20) extending along a longitudinal axis (X) oriented upstream to downstream and comprising an external wall (21) from which the stator blade (22) projects along a radial axis (Y), the support device (1) comprising: • At least one housing (2) configured to radially receive a mounting foot (23) for the stator blade (22), • An upstream support foot (5) and a downstream support foot (6) connected respectively to an upstream end (3) and a downstream end (4) of the housing (2) and configured to be mounted on the external wall (21) of the aircraft turbomachine (20), • The support device (1) being characterized in that the downstream support foot (6) comprises at least one cavity (8) in which at least one shock indicator (10) is mounted, the cavity (8) having a contour (9) of predetermined shape,the shock indicator (10) being configured to change its visual appearance irreversibly in the event of deformation (D) of the contour (9) of the cavity (8) so as to visually detect an impact (A) exerted on the stator blade (22).

2. Support device (1) according to claim 1, wherein, under nominal conditions, the shock indicator (10) is in contact with the contour (9) of the cavity (8).

3. Support device (1) according to any one of claims 1 and 2, wherein the shock indicator (10) is passive.

4. Support device (1) according to any one of claims 1 to 3, wherein the shock indicator (10) comprises a material adapted to break or deform plastically by compression in the event of deformation (D) of the contour (9) of the cavity (8).

5. Support device (1) according to any one of claims 1 to 4, wherein the cavity (8) of the downstream support foot (6) is through.

6. Support device (1) according to any one of claims 1 to 5, wherein the contour (9) of the cavity (8) has a transverse width decreasing from upstream to downstream, preferably teardrop-shaped with a wide end (12) upstream and a narrow end (13) downstream aligned transversely with respect to the longitudinal axis (X).

7. Support device (1) according to any one of claims 1 to 6, wherein the downstream support foot (6) has a groove (11) extending in the longitudinal continuation of the cavity (8).

8. Aircraft turbomachine (20) extending along a longitudinal axis (X) oriented upstream to downstream and comprising: • An outer wall (21), preferably in the form of an external compressor casing, • An unshrouded stator (29) comprising at least one stator blade (22) projecting out from the outer wall (21) along a radial axis (Y), • At least one support device (1) according to any one of claims 1 to 7, wherein the upstream support foot (5) and the downstream support foot (6) are mounted on the outer wall (21), the stator blade (22) comprising a mounting foot (23) mounted radially in the housing (2) of the support device (1).

9. A method of using a support device (1) according to any one of claims 1 to 7, wherein the shock indicator (10) changes its visual appearance irreversibly during a deformation (D) of the contour (9) of the cavity (8) so as to visually detect an impact (A) exerted on the stator blade (22).

10. A method for manufacturing a support device (1) according to any one of claims 1 to 7, comprising: • A step of forming the cavity (8) in the downstream support foot (6), • A step of filling the cavity (8) with a malleable material (M), • A step of hardening the malleable material (M), so as to form the shock indicator (10).

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