Aircraft turbomachine fan and its method of use

Abstract

An aircraft turbomachine (30) fan (1) comprising blades (3) supported by a rotating hub about a longitudinal axis (X), an outer shell (4) integral with the rotating hub, and a fan compartment defined radially between the rotating hub and the outer shell (4), the outer shell (4) comprising: - at least one frame (7) defining an inspection opening (8) for accessing the fan compartment, and - at least one panel (9) removably mounted on the frame (7) to close the inspection opening (8), the panel (9) having at least one first end and a second opposite end extending against an inner face of the frame (7) facing the longitudinal axis (X). Figure 1

Description

Title of the invention: Aircraft turbomachine blower and its method of use technical field

[0001] The present invention relates to the field of aircraft turbomachine blowers.

[0002] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new types of aircraft and those already in service, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively working for several years now to contribute to the fight against climate change.

[0003] 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 aeronautical components and products that are less energy-intensive, more environmentally friendly, and whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0004] This sustained research and development work focuses in particular on new generations of aircraft turbomachinery known as "unfaired" in that no nacelle surrounds the turbomachine, thus reducing its mass. Such an unfaired aircraft turbomachine typically comprises, upstream, an unfaired fan that guides an airflow through a duct comprising, from upstream to downstream, 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 diameter fan, particularly one exceeding 3.5 m, to improve thrust.

[0005] In practice, the fan comprises a set of blades supported by a rotating hub connected in rotation to a shaft of the aircraft turbomachine via a reduction gear. Each blade comprises a foot mounted in a housing of the rotating hub, a blade extending radially outward, and a platform connecting the foot and the blade. To protect the rotating hub and ensure aerodynamics, the unshod fan comprises an external ferrule extending radially around the rotating hub and integral to it. Mounting openings are formed in the outer shell for the blades. A fan compartment is defined radially between the rotating hub and the outer shell and houses the blade platforms as well as one or more aircraft turbomachinery components, such as a telemetry unit.

[0006] To reduce aircraft downtime during fan maintenance or inspection, it is known to provide access openings in the outer shell downstream of the mounting openings. Such access openings are closed by removable panels screwed externally onto the outer shell. During maintenance, the operator removes the panel by loosening the screws, allowing easy and convenient access to the fan compartment without having to disassemble the blades and the outer shell.

[0007] In practice, one or more panel fasteners are likely to loosen under the effect of centrifugal forces generated by the fan's rotation. This can eventually disrupt aerodynamics, generate vibrations, and in some cases lead to the loss of a panel during aircraft flight. To avoid this, one solution is to implement procedures for regularly checking the panels' stability, which is cumbersome and costly. Another solution would be to use stronger and more numerous fasteners, which would undesirably complicate access to the inspection openings.

[0008] The invention thus aims to eliminate one or more of the aforementioned drawbacks in aircraft turbomachinery fans, particularly those without shrouds. PRESENTATION OF THE INVENTION

[0009] The invention relates to an aircraft turbomachine fan comprising a hub rotating about a longitudinal axis and a plurality of blades carried by the rotating hub, the fan comprising an outer shell integral with the rotating hub and a fan compartment defined radially between the rotating hub and the outer shell, the outer shell comprising: • at least one frame defining an access opening to the blower compartment, • at least one panel mounted removably on the frame to close off the inspection opening.

[0010] The invention is remarkable in that the panel of the external ferrule of the blower has at least a first end and a second end, opposite to the first end, which extend in support against an internal face of the frame turned towards the longitudinal axis.

[0011] The outer face of the panel recreates the aerodynamic surface of the outer ferrule at the inspection opening. The first end and the second end of the The panels have an outer face resting on the inner face of the access opening. The first and second ends are said to be opposite in that they form two portions of the perimeter which are not adjacent and extend substantially opposite each other so as to hold the entire panel against the frame.

[0012] Mounting the panel against the inner face of the frame allows the panel ends to be pressed against the frame by centrifugal force, thus preventing any risk of the panel coming loose during flight. Therefore, even if the panel mounting on the frame is subject to play or even weakened, the frame radially retains the panel by overlapping its ends. This internal mounting also reduces stress on the mounting elements, thereby decreasing the risk of play or weakening. The procedures for verifying the panel mounting by an operator can thus be less frequent. Furthermore, access to the inspection opening remains simple and convenient. The internal mounting of the panel allows the use of a small number of inexpensive mounting elements to ensure sufficient strength.

[0013] According to a preferred design, the blower is of the unenclosed type. This allows simple and easy access to the blower compartment.

[0014] According to a preferred aspect, the first end and the second end are opposed in the circumferential direction with respect to the longitudinal axis for better holding under the effect of centrifugal force.

[0015] According to one aspect of the invention, the first end of the panel extends along the entire length or width of the panel. Preferably, the second end of the panel extends along the entire length or width of the panel. This ensures that the panel is properly positioned against the inner face of the frame during the rotation of the hub.

[0016] According to one aspect of the invention, the panel has a perimeter comprising the first end and the second end, the entire perimeter of the panel being in contact with the inner face of the frame. This ensures optimal contact of the panel with the inner face of the frame during the drive of the rotating hub.

[0017] According to a preferred aspect of the invention, the longitudinal axis of the fan's rotating hub is oriented from upstream to downstream along the direction of airflow during a thrust phase of the aircraft turbomachine, with the inspection opening of the outer shell extending downstream of the blades. This improves the aerodynamics of the fan's outer shell. Alternatively or complementarily, one or more inspection openings extend upstream of the blades.

[0018] According to one aspect of the invention, the frame has two sides extending in an oblique direction forming an angle with respect to a longitudinal direction parallel to the longitudinal axis. This reduces the drag generated by the boundary layer of airflow around the outer ferrule circulating at the joint between the frame and the panel.

[0019] According to one aspect of the invention, the outer ferrule comprises at least one fastener mounted through the frame and in the first end of the panel, the fastener being removable from an outer face of the frame opposite the inner face. Preferably, at least one fastener removable from the outer face of the frame is mounted through the frame and in the second end of the panel. Preferably, the fastener is in the form of a screw. This allows the panel to be secured to the frame in a reversible, simple, and practical manner.

[0020] According to another aspect of the invention, the outer ferrule comprises at least one movable locking element accessible from an outer face of the frame opposite the inner face, the first end of the panel being sandwiched between the locking element and the frame. Preferably, the second end of the panel is sandwiched between the frame and a movable locking element accessible from the outer face of the frame. Preferably, the locking element is in the form of a cleat. This allows the panel to be held against the frame in a reversible, simple, and practical manner.

[0021] According to one aspect of the invention, the panel comprises a first part and a second part, the first part comprising the first end, the second part comprising the second end, the first part comprising a third end, opposite the first end, cooperating with a fourth end of the second part, opposite the second end. This allows the panel to be extracted more easily from the access opening.

[0022] According to a preferred aspect of the invention, the outer ferrule comprises: • a plurality of frames distributed around the circumference of the outer shell, each defining an inspection opening to access the blower compartment, • at least one panel mounted removably on each frame to close the inspection opening, each panel having at least a first end and a second end, opposite the first end, which extend in support against an internal face of the frame facing the longitudinal axis.

[0023] This allows easy and convenient access to the entire blower compartment.

[0024] The invention also relates to an aircraft turbomachine comprising a blower as described above and a gas generator driving the blower in rotation.

[0025] The invention also relates to a method of using a blower as described above, in which the rotational drive of the rotating hub presses the first end and the second end of the panel against the inner face of the The frame is secured by centrifugal force. This prevents any risk of the panel falling off, even if there is some play in the panel mounting.

[0026] The invention also relates to a method for maintaining a blower as described above, consisting of removing the panel from the frame and extracting the panel from the blower through the inspection opening. Advantageously, the frame removal is simple, convenient, and quick for an operator. PRESENTATION OF THE FIGURES

[0027] 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.

[0028] Fig. 1 is a schematic perspective representation of an unfaired aircraft turbomachine comprising an unfaired fan according to one embodiment of the invention.

[0029] Fig. 2 is a schematic perspective representation of the outer shell of the unfaired blower of Fig. 1.

[0030] Fig. 3 is a schematic cross-sectional representation of the panels sealing the inspection openings of the external shell of the unfaired blower of Fig. 2.

[0031] Fig. 4 is a schematic representation of the dismantling of a panel to access an inspection opening of the external shell of the shrouded blower of Fig. 2.

[0032] The [Fig.5] is a schematic perspective representation from inside a panel closing an inspection opening of the outer shell of the faired blower of the [Fig.2].

[0033] Fig. 6 is a schematic cross-sectional representation of the panels sealing the inspection openings of the external shell of the unfaired blower according to another embodiment of the invention.

[0034] The [Fig.7] is a schematic perspective representation from inside a panel closing an inspection opening of the external shell of the faired blower according to another embodiment.

[0035] Fig. 8 is a schematic cross-sectional representation of the panels sealing the inspection openings of the external shell of the unfaired blower according to another embodiment of the invention.

[0036] Fig. 9 is a schematic perspective representation of the outer ferrule with oblique panels according to another embodiment of the invention.

[0037] It should be noted that the figures explain the invention in detail to put into works the invention, the said figures being of course able to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0038] With reference to [Fig. 1], the invention is presented in the context of an unshod-type aircraft turbomachine 30 fan 1, that is, no shroud surrounds the fan 1. Such an unshod-type fan 1 usually has a large diameter greater than 3.5 m and a reduced mass, which allows it to generate significant thrust. The invention also applies to shod aircraft turbomachine 30 fans for which access to the fan compartment is desired.

[0039] As illustrated in [Fig. 1], the aircraft turbomachine 30 conventionally comprises an air duct 31 extending along a longitudinal axis X and in which an airflow flows from upstream to downstream in a gas generator during a thrust phase of the aircraft turbomachine 30. The gas generator conventionally comprises, from upstream to downstream, one or more compressors, a combustion chamber, and one or more turbines. The fan 1 conventionally extends upstream of the gas generator and guides the airflow in the air duct 31. In this example, the aircraft turbomachine 30 is in the form of a turboprop in which the fan 1 is driven in rotation by the turbine(s) via a speed reducer.

[0040] In the example of [Fig.1], the aircraft turbomachine 30 is of the unfaired type, that is to say that no nacelle surrounds the aircraft turbomachine 30. Also in this example, the compressor of the aircraft turbomachine 30 includes upstream an unfaired stator 32 whose stator blades extend radially outward from the air stream 31 to promote thrust.

[0041] With reference to Figures 1 and 2, the fan 1 comprises a rotating hub 2 about the longitudinal axis X carrying a set of blades 3. Each blade 3 typically comprises a foot (not shown) mounted in a housing of the rotating hub 2, a blade 18 extending radially outward, and a platform 19 connecting the foot and the blade 18. To protect the rotating hub and ensure aerodynamics, the fan 1 comprises an outer shell 4 extending radially around the rotating hub 2 and integral with it. The outer shell 4, either a single piece or comprising several portions assembled together, includes mounting openings 6 through which the blades 3 pass to allow the blades 18 to extend outward. A blower compartment 5 is defined radially between the rotating hub 2 and the outer shell 4 and houses the blade platforms 19 3 as well as one or more aircraft turbomachine equipment 30, such as a telemetry box.The blower compartment 5 corresponds to the inside of the outer shell 4.

[0042] According to the invention and as illustrated in Figures 1 to 4, the outer shell 4 comprises at least one frame 7 defining an inspection opening 8 (see [Fig. 4]) for accessing the blower compartment 5. Also according to the invention, the outer shell 4 comprises at least one panel 9 removably mounted on the frame 7 to close the inspection opening 8 (see [Fig. 3]). Again according to the invention, the panel 9 has at least a first end 10 and a second end 11, opposite the first end 10, which extend in contact with an inner face 14 of the frame 7 facing the longitudinal axis X.

[0043] Mounting the panel 9 against the inner face 14 of the frame 7 advantageously eliminates the risk of losing a panel 9 during aircraft flight. Indeed, the rotational drive of the fan 1, and in particular of the outer ferrule 4, allows the ends 10, 11 of the panel 9 to be pressed against the frame 7 by centrifugal force. Thus, even if the mounting of the panel 9 on the frame 7 is subject to play or even weakened, the frame 7 overlaps the panel 9 at the ends 10, 11, which radially retains the panel 9 and prevents it from passing through the inspection opening 8. Such an internal mounting also reduces the stress on the mounting elements, thereby decreasing the risk of play or weakening. The procedures for verifying the mounting of the panel 9 by an operator can therefore be less frequent.

[0044] Furthermore, access to the inspection opening 8 remains simple and convenient. The internal mounting of the panel 9 allows the use of few, inexpensive mounting elements to ensure sufficient strength. As will be explained later, the panel 9 is designed, when removed from the frame 7, to be extracted from the blower 1 via the inspection opening 8. As illustrated in [Fig. 4], since the panel 9 has a larger surface area than the inspection opening 8, its extraction is achieved by tilting the panel 9, taking advantage of the free volume present in the blower compartment 5.

[0045] According to a preferred aspect illustrated in Figures 1 and 2, the outer shell 4 comprises several frames 7 distributed around the circumference of the outer shell 4, each defining an inspection opening 8. A panel 9 is removably mounted on the inner face 14 of each frame 7 to close the associated inspection opening 8. This provides several access points to the fan compartment 5 to facilitate inspection or maintenance. In this example, the frames 7 are aligned transversely with respect to the longitudinal axis X to minimize bulk. Preferably, and as illustrated in [Fig. 1], the frame(s) 7 are mounted downstream of the mounting openings 6 to improve the aerodynamics of the unshod fan 1. Alternatively or complementaryly, one or more frames 7 are mounted upstream of the mounting openings 6. A single frame 7 and a single panel 9 are hereafter described. panel 9, this description being valid for each.

[0046] As illustrated in Figures 3 and 4, the panel 9 covers the entire surface of the inspection opening 8 to seal it. The outer face of the panel 9 preferably extends in line with the frame 7 to improve the aerodynamics of the outer ferrule 4. The outer face of the panel 9 is exposed to the outside airflow. The first end 10 and the second end 11 of the panel 9 protrude on either side of the inspection opening 8, radially inwards, so that their external face rests against the internal face 14 of the frame 7. The first end 10 and the second end 11 are said to be opposite in that they form two portions of the perimeter 12 which are not adjacent and extend substantially opposite each other so as to retain the whole panel 9 against the frame 7. Preferably, the first end 10 and the second end 11 are opposite in a circumferential direction with respect to the longitudinal axis.

[0047] Preferably, the first end 10 and the second end 11 of the panel 9 extend over the entire width or length of the panel 9, that is, they form two opposite sides of the panel 9, namely the short sides or the long sides. This ensures good support of the panel 9 on the frame 7 and thus promotes clamping when the blower 1 is rotated. Preferably, and as illustrated in [Fig. 5], the entire perimeter of the panel 9, formed by the four sides of the panel 9, rests against the inner face 14 of the frame 7 to maximize support and clamping.

[0048] According to a first embodiment of the invention illustrated in Figures 3 to 5, the panel 9 is removably mounted on the inner face 14 of the frame 7 by means of fasteners 16, such as screws, passing through the frame 7 and the first end 10 of the panel 9. One or more other fasteners 16 pass through the frame 7 and the second end 11 of the panel 9. The fasteners 16 are inserted from the outer face 15 of the frame 7 so as to be easily loosened during maintenance by an operator. Nuts 17, preferably integral with the panel 9, allow the screws 16 to be tightened.

[0049] As illustrated in [Fig. 5], the fastening elements 16 are preferably distributed around the entire perimeter 12 of the panel 9 for good mechanical strength. According to a preferred aspect illustrated in [Fig. 5], the perimeter 12 of the panel 9 includes protruding fastening tabs 24 configured to receive the fastening elements 16. This helps to reduce the mass of the panel 9 and its width, which can facilitate assembly and disassembly.

[0050] According to a second embodiment of the invention illustrated in Figures 6 and 7, the panel 9 is removably mounted on the inner face 14 of the frame 7 by means of movable locking elements 13, such as pivoting cleats. The locking elements 13 allow the panel 9 to be sandwiched at its ends. 10, 11 between the locking elements 13 and the frame 7. The locking elements 13 are preferably mounted on the inner face 14 of the frame 7, in this example by screws passing through the frame 7, which allows the locking elements 13 to pivot from the outside. A small number of locking elements 13 are required, which can be distributed on only two sides of the frame 7, and the ends 10, 11 can advantageously be narrower.

[0051] Preferably, and as illustrated in [Fig. 6], the ends 10, 11 of the panel 9, and preferably all or part(s) of the perimeter 12, are hooked in a U-shape open outwards to cooperate with the frame 7, which is hooked and curved inwards. This facilitates the positioning of the panel 9 and allows for better fixing and sealing, both with the locking elements 13 and the fastening elements 16.

[0052] According to a preferred aspect illustrated in [Fig.9], the frame 7 (and consequently the panel 9) is oblique, that is to say, it comprises: • two first opposite sides 25, in this example the short sides, extending along an oblique direction Y1 forming an angle α, preferably non-zero, preferably between 5° and 30° with respect to a longitudinal direction XI parallel to the longitudinal axis X, and • two second opposite sides 26, in this example the long sides, extending transversely with respect to the longitudinal axis X.

[0053] Such an oblique frame 7 and such an oblique panel 9 make it possible to reduce the drag of the airflow at the joints between the frame 7 and the panel 9. Alternatively, as illustrated in [Fig.2], the first opposite sides 25 extend longitudinally.

[0054] According to a preferred aspect illustrated in [Fig. 8], the panel 9 comprises a first part 20 on which the first end 10 is formed and a second part 21 on which the second end 11 is formed. The first part 20 and the second part 21 are juxtaposed and their outer faces extend in line with each other to enhance the aerodynamics of the outer ferrule 4. The first part 20 comprises a third end 22 opposite the first end 10 and cooperating with a fourth end 23 of the second part 21, opposite the second end 11, in this example by complementary shapes. In this example, all or part of the third end 22 is preferably hooked and curved inwards, and all or part of the fourth end 23 is hooked in the shape of a U open outwards.

[0055] Advantageously, during the rotation of the blower 1, this allows the first part 20 and the second part 21 of the panel 9 to be pressed together under the effect of centrifugal force without using any fastening or blocking elements between the first part 20 and the second part 21 of panel 9. Parts 20 and 21 of panel 9 are, as before, removably mounted on frame 7. Furthermore, during maintenance, it is sufficient to detach the first part 20 and the second part 21 from frame 7 to separate the first part 20 from the second part 21. Each part 20 and 21 is then extracted from the access opening 8, in a simplified manner because they are smaller than a complete panel 9. Advantageously, this solution allows for a large access opening 8. Assembly and disassembly are facilitated.

[0056] The invention has been described for inspection openings 8 and panels 9 of quadrilateral shape, particularly with rounded corners. The invention also applies to inspection openings 8 and panels 9 of different shapes, for example oval or elliptical. The first end 10 and the second end 11 may be of different lengths and are said to be substantially opposite in that they together allow the panel 9 to be held against the frame 7 on either side. In order to install or remove the panel 9, its greatest width must be less than the greatest length of one of the inspection openings 8, and the available internal space in the blower compartment must allow the panel 9 to be moved and pivoted to extend and retract it by positioning the greatest width of the panel 9 along a sufficient length of the inspection opening 8.

[0057] The invention has been presented for inspection openings 8 and panels 9 located downstream of the blades 3 but also applies to inspection openings 8 and panels 9 located upstream of the blower 1. As described previously, the invention also applies to a shrouded blower 1 comprising a rotating ferrule in which at least one inspection opening 8 is provided.

[0058] The invention also relates to a method of using the blower 1, in which the panel 9 is mounted on the frame 7, as illustrated in Figures 2 and 3 and Figures 5 to 9. The rotational drive of the rotating hub 2 has the effect of pressing the ends 10, 11 of the panel 9 against the inner face 14 of the frame 7 in an outward radial direction. This prevents any risk of loss of the panel 9, even if the fixing elements 16 or the locking elements 13 have some play.

[0059] The invention also relates to a method for maintaining the blower 1 consisting of removing the panel 9 from the frame 7 by loosening the fastening elements 16 in the example of [Fig. 4] or by pivoting the locking elements 13 in the example of Figures 6 and 7. As illustrated in [Fig. 4], the panel 9 is then extracted from the blower 1 via the inspection opening 8, typically by pivoting it along the diagonal of the frame 7 and taking advantage of the free space offered by the blower compartment 5. This allows an operator to easily and conveniently access the blower compartment 5.

[0060] Once maintenance or inspection is completed, the panel 9 is inserted into the access opening 8, typically by pivoting it along the diagonal of the frame 7 and taking advantage of the free volume offered by the blower compartment 5. The panel 9 is then remounted on the frame 7, for example by tightening the fixing elements 16 or by pivoting the locking elements 13.

Claims

Demands

1. An aircraft turbomachine (30) fan (1) comprising a rotating hub (2) about a longitudinal axis (X) and a plurality of blades (3) carried by the rotating hub (2), the fan (1) comprising an outer shell (4) integral with the rotating hub (2) and a fan compartment (5) defined radially between the rotating hub (2) and the outer shell (4), the outer shell (4) comprising: • at least one frame (7) defining an inspection opening (8) for accessing the fan compartment (5), • at least one panel (9) removably mounted on the frame (7) for closing the inspection opening (8), the fan (1) being characterized in that the panel (9) has at least a first end (10) and a second end (11), opposite the first end (10), which extend in support against an inner face (14) of the frame (7) facing the longitudinal axis (X).

2. Blower (1) according to claim 1, wherein the first end (10) extends over the entire length or width of the panel (9).

3. Blower (1) according to any one of claims 1 and 2, wherein the panel (9) has a perimeter (12) comprising the first end (10) and the second end (11), the entire perimeter (12) of the panel (9) being in contact with the inner face (14) of the frame (7).

4. Blower (1) according to any one of claims 1 to 3, wherein the frame (7) has two sides (25) extending in an oblique direction (Yl) forming an angle (a) with respect to a longitudinal direction (XI) parallel to the longitudinal axis (X).

5. Blower (1) according to any one of claims 1 to 4, wherein the outer ferrule (4) comprises at least one fastening element (16) mounted through the frame (7) and in the first end (10) of the panel (9), the fastening element (16) being removable from an outer face (15) of the frame (7) opposite the inner face (14).

6. Blower (1) according to any one of claims 1 to 4, wherein the outer ferrule (4) comprises at least one locking element (13) movable from an outer face (15) of the frame (7) opposite the face internal (14), the first end (10) of the panel (9) being sandwiched between the blocking element (13) and the frame (7).

7. Blower (1) according to any one of claims 1 to 6, wherein the panel (9) comprises a first part (20) and a second part (21), the first part (20) comprising the first end (10), the second part (21) comprising the second end (11), the first part (20) comprising a third end (22), opposite the first end (10), cooperating with a fourth end (23) of the second part (21), opposite the second end (11).

8. Aircraft turbomachine (30) comprising a fan (1) according to any one of claims 1 to 7 and a gas generator rotating the fan (1).

9. A method of maintaining a blower (1) according to any one of claims 1 to 7, consisting of removing the panel (9) from the frame (7) and extracting the panel (9) from the blower (1) via the inspection opening (8).

10. A method of using a blower (1) according to any one of claims 1 to 7, wherein the rotational drive of the rotating hub (2) presses the first end (10) and the second end (11) of the panel (9) against the inner face (14) of the frame (7) by centrifugal effect.

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