AIR INTAKE LIP OF A TURBOMACHINE NACELLE COMPRISING AN ACOUSTIC DEVICE AND METHOD FOR PRODUCING SUCH A LIP

Abstract

The invention relates to an air intake lip of an aircraft turbomachine nacelle extending along an axis X, in which an air flow circulates from upstream to downstream, the lip extending annularly about the X-axis and having an inner wall facing the X-axis and an outer wall which is opposite the inner wall, the inner wall and the outer wall being connected by an upstream wall so as to delimit an annular cavity, the lip comprising an annular acoustic device mounted in the annular cavity. The lip has a first module, comprising the outer wall, the wall and a front wall forming an upstream portion of the inner wall, and a second module, comprising the acoustic device and a front skin forming a downstream portion of the inner wall, the first module and the second module being secured together so that the front wall and the front skin together form the inner wall of the lip.

Claims

1-6. (canceled)

7. A lip of an air intake of an aircraft turbomachine nacelle extending along an axis X in which an air flow circulates from upstream to downstream, the lip annularly extending about axis X and comprising an internal wall pointing to axis X and an external wall which is opposite to the internal wall, the internal wall and the external wall being connected through an upstream wall so as to delimit an annular cavity, the lip comprising an annular acoustic device mounted in the annular cavity, the lip comprising: a first module, comprising the external wall, the upstream wall and a front wall forming an upstream portion of the internal wall; and a second module, comprising the acoustic device and a front skin forming a downstream portion of the internal wall, the first module and the second module being secured together so that the front wall and the front skin together form the internal wall of the lip, the front wall of the first module being spaced radially from the front skin of the second module by at least one spacer stud so as to form between them at least one blow-out opening.

8. The lip of an air intake according to claim 7, wherein the second module comprising a rear skin, the acoustic device is housed between the front skin and the rear skin.

9. The lip of an air intake according to claim 8, wherein the front wall of the first module is radially internal to the front skin of the second module at an interface zone between the front wall and the front skin.

10. The lip of an air intake according to claim 7, wherein the spacer stud has an aerodynamic shape so as to guide an air flow into the blow-out opening.

11. The lip of an air intake according to claim 7, wherein the spacer stud comprises an opening for guiding a mechanical connection member configured to secure the front wall of the first module to the front skin of the second module.

12. A method for manufacturing the lip of an air intake according to claim 7, comprising a step of independently manufacturing the first module and the second module, and a step of securing the first module to the second module so that the front wall and the front skin together form the internal wall of the lip.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The invention will be better understood upon reading the following description, which is given solely by way of example, and refers to the appended drawings given as non-limiting examples, in which identical references are given to similar objects and in which:

[0037] FIG. 1 is a schematic representation in a longitudinal cross-section view of a turbomachine comprising a nacelle with an air intake;

[0038] FIG. 2 is a schematic representation in a longitudinal cross-section view of an air intake comprising an acoustic device according to prior art;

[0039] FIG. 3 is a schematic representation in a longitudinal cross-section view of a step of manufacturing an air intake according to prior art;

[0040] FIG. 4 is a schematic representation in a longitudinal cross-section view of a lip comprising a first main module and a second acoustic module assembled together;

[0041] FIG. 5 is a schematic representation of the second acoustic module for a lip according to the invention;

[0042] FIG. 6 is a schematic perspective representation of a lip according to the invention with an inner partition wall;

[0043] FIGS. 7A and 7B are schematic representations in a longitudinal cross-section view and a partial perspective view of a first embodiment of an assembly of a lip comprising blow-out openings;

[0044] FIGS. 8A and 8B are schematic longitudinal section and partial perspective representations of a second embodiment of an assembly of a lip comprising blow-out openings;

[0045] FIG. 8C is a schematic representation in a longitudinal cross-section view of a downstream end of the first main module according to one aspect of the invention;

[0046] FIG. 9 is a schematic representation in a longitudinal cross-section view of a third embodiment of an assembly of a lip comprising blow-out openings;

[0047] FIG. 10 is a schematic perspective representation of an assembly of a lip comprising blow-out openings and a filling member;

[0048] FIGS. 11A and 11B are partial schematic perspective representations of an assembly of a lip comprising blow-out openings and contoured spacer studs.

[0049] It should be noted that the figures set out the invention in detail for implementing the invention, said figures of course being able to serve to better define the invention where appropriate.

DETAILED DESCRIPTION

[0050] With reference to FIG. 4, an air intake 2 of an aircraft turbomachine nacelle according to an embodiment of the invention, in particular, a turbojet engine nacelle is represented. The turbomachine extends along an axis X and allows circulation, during a thrust, of an air flow from upstream to downstream. Hereafter, axis X is oriented from upstream to downstream. With reference to FIG. 6, the air intake 2 comprises an upstream portion 2a, known to the person skilled in the art as lip 2a, and a downstream portion 2b. In this example, the lip 2a is separated from the downstream portion 2b by an inner partition wall 25.

[0051] The lip 2a annularly extends about axis X and comprises an internal wall 21 pointing to axis X and an external wall 22 that is opposite to the internal wall 21. The walls 21, 22 are connected through an upstream wall 23 so as to delimit an annular cavity 20. Thus, the lip 2a enables the incoming air flow to be separated into an internal air flow guided by the internal wall 21 and an external air flow guided by the external wall 22. Hereafter, the terms internal and external are defined radially with respect to axis X of the turbomachine. The lip 2a comprises an annular acoustic device 50 mounted in the annular cavity 20.

[0052] According to the invention, the lip 2a comprises a first module M1, comprising the external wall 22, the upstream wall 23 and a front wall 24 that forms an upstream portion of the internal wall 21. The lip 2a further comprises a second module M2, comprising the acoustic device 50 and a front skin 51 that forms a downstream portion of the internal wall 21, the first module M1 and the second module M2 being secured together so that the front wall 24 and the front skin 51 together form the internal wall 21 of the lip 2a. Preferably, the internal wall 21 has an aerodynamic shape to optimally guide the air flow in the secondary stream of the turbomachine.

[0053] In other words, contrary to prior art which taught to make a one-piece internal wall 21, a modular internal wall 21 which comprises a front wall 24, forming an upstream portion, and a front skin 51, forming a downstream portion, which are secured during assembly, is set forth. As will be set forth later, such a modular design allows a second acoustic module M2 to be formed independently, thereby facilitating the manufacture thereof and limiting the risk of defects during assembly.

[0054] As illustrated in FIG. 4, the first module M1, also referred to as the main module M1, has a structure similar to prior art except that it does not have a long internal wall but only a shortened internal wall called a front wall 24. Preferably, the main module M1 is made of a metallic material, preferably, resistant to high temperatures, for example, of aluminum. Several embodiments of a main module M1 will be set forth below. The first module M1 is preferably as one-piece.

[0055] In this embodiment, the first module M1 is made by forming (explosively or otherwise) or by flow forming.

[0056] As illustrated in FIG. 4, the second module M2, also referred to as the acoustic module M2, has an acoustic device 50 which is, in this example, in the form of a honeycomb structure. The acoustic device 50 comprises a plurality of acoustic, preferably metallic, cells. Nevertheless, it goes without saying that the acoustic device 50 could be in other forms.

[0057] With reference to FIGS. 4 and 5, the second module M2 comprises a front skin 51 and a rear skin 52 between which the acoustic device 50 is mounted. The front skin 51 of the second acoustic module M2 is configured to extend as an extension of the front wall 24 of the first module M1. The front skin 51 is preferably made of a metallic material, especially, of aluminum.

[0058] The front skin 51 comprises a plurality of perforations so as to put the acoustic device 50 in communication with the air flow circulating inside the lip 2a. The perforations may be made before or after assembly of the second module M2. Similarly, the perforations may be made before or after assembly of modules M1, M2.

[0059] The rear skin 52 defines a concavity in which the acoustic device 50 is housed. The rear skin 52 is preferably made of a metallic material, especially of aluminum. The acoustic device 50 is secured, preferably by soldering, to the rear skin 52.

[0060] As illustrated in FIG. 5, in a longitudinal cross-section view, the rear skin 52 comprises a concave central portion 52b and two end portions 52a that are secured to the front skin 51. Such securing is simple to implement since it is carried out independently of the first module M1. Preferably, the rear skin 52 is secured to the front skin 51 by soldering, welding or the like or by mechanical assembly. Advantageously, the second module M2 has a reduced overall size thereby facilitating its soldering and assembly in an oven. Moreover, upon manufacturing the second module M2, mechanical properties of the first module M1 are advantageously not affected.

[0061] Preferably, the ends 51a of the front skin 51 are longer than those of the rear skin 52 so as to be secured to the first module M1 as will be set forth hereafter.

[0062] After assembly, the second module M2 can be stored, handled and used independently of the first module M1, which significantly simplifies logistics and assembly of the lip 2a.

[0063] Advantageously, the first module M1 and the second module M2 can be obtained by different methods.

[0064] Advantageously, the modules M1, M2 are manufactured independently and then assembled together. The assembly is preferably performed mechanically, by welding (laser, friction, electron beam, etc.) or the like.

[0065] With reference to FIG. 6, according to one aspect of the invention, the air intake 2 comprises an inner partition wall 25 so as to form a closed annular cavity 20 in which a de-icing air flow can especially circulate. In this example, the inner partition wall 25 is mounted between the external wall 22 of the first module M1 and the rear skin 52 of the second module M2. Such a design is advantageous since it allows, on the one hand, to maximize the dimensions of the acoustic device 50 and, on the other hand, to facilitate mounting of the inner partition wall 25 which can be previously mounted to the first module M1 or to the second module M2. Nevertheless, it goes without saying that the acoustic device 50 could be independent of the inner partition wall 25 and spaced from the latter, in particular, the inner partition wall 25 could be located downstream of the acoustic device 50.

[0066] In this example, the assembly of an inner partition wall 25 in the air intake 2 has been set forth. Such an inner partition wall 25 is not required and may be omitted depending on the configurations of the air intake 2. Hereinafter, for the sake of clarity and brevity, such an inner partition wall 25 is not represented, but of course could be provided.

[0067] As previously indicated, the air intake 2 comprises an upstream portion 2a and a downstream portion 2b. Following its manufacture, the lip 2a may be mounted to a downstream portion 2b to form the air intake 2. Preferably, the downstream portion 2b comprises an acoustic device. According to one aspect of the invention, the acoustic device of the downstream part 2b is independent of the acoustic device 50 of the lip 2a. According to another aspect of the invention, the acoustic device continuously extends between the downstream portion 2b and the lip 2a to provide optimal acoustic attenuation. An inner partition wall 25 between the lip 2a and the downstream portion 2b of the air intake 2 has been set forth but is optional.

[0068] According to one aspect of the invention, the annular cavity 20 comprises at least one injector of a hot air flow, in particular, for de-icing the lip 2a. According to one aspect of the invention, the lip 2a comprises at least one blow-out opening in the internal wall 21, preferably a plurality of blow-out openings in order to guide the hot air flow out of the annular cavity 20 and thereby de-ice the internal wall 21.

[0069] Several embodiments of blow-out openings will now be set forth with reference to FIGS. 7A through 11B.

[0070] As illustrated in FIGS. 7A and 7B, according to a first embodiment, the first module M1 and the second module M2 are secured together at an interface zone in which one end 51a of the front skin 51 of the second module M2 is secured to the front wall 24 of the first module M1. Preferably, in the interface zone, the front skin 51 is radially internal to the front wall 24 of the first module M1 so as to allow securing in a radial direction, for example, by welding or mechanical connection. In this embodiment, three connections L are represented in FIG. 7B.

[0071] In order to form a lip 2a having an internal wall 21 having an aerodynamic curvature, the front skin 51 of the second module M2 is curved so as to comprise an end portion 51a superimposed to the front wall 24 of the first module M1 to allow attachment and a central portion 51b as an extension of the front wall 24 of the first module M1 as illustrated in FIG. 7A.

[0072] Preferably, as illustrated in FIG. 7A, the downstream end 24a of the front wall 24 is beveled so as to snugly fit the curvature of the front skin 51 of the second module M2, with its radially external surface converging radially inwardly along an upstream-downstream direction. Such a bevel is simple to make and avoids a significant deformation of the front skin 51 in order to keep an aerodynamic profile. The bevel thus faces a curvature of the front skin 51 to obtain a continuous internal wall 21.

[0073] As illustrated in FIGS. 7A and 7B, the front wall 24 of the first module M1 comprises a plurality of blow-out openings 31 that are formed away from the downstream end of the front wall 24. In this example, the blow-out openings 31 extend substantially radially into the material of the front wall 24. Such an independent blow-out opening 31 is known to the skilled person as “separated slot”. With reference to FIG. 7B, each blow-out opening 31 is in this example in the form of an azimuthally directed slot. Of course, the shape and direction could be different.

[0074] The blow-out openings 31 are formed in the first module M1 independently of the second module M2. With reference to FIG. 7A, the blow-out openings 31 are formed in an extra thickness of the front wall 24, such an extra thickness is nevertheless not necessary.

[0075] According to a second embodiment, as illustrated in FIGS. 8A and 8B, the first module M1 and the second module M2 are secured together at an interface zone in which the end 51a of the front skin 51 of the second module M2 is secured to the front wall 24 of the first module M1. Preferably, in the interface zone, the front skin 51 is radially internal to the front wall 24 of the first module M1 so as to allow securing along a radial direction.

[0076] In this second embodiment, the front wall 24 and the front skin 51 are spaced apart radially by a plurality of spacer studs 6, or wedges, mounted between the front wall 24 and the front skin 51. Preferably, at least one spacer stud 6 comprises a radial passage opening for guiding a mechanical connection member L, for example, a rivet. Thus, when assembling the first module M1 with the second module M2, the front wall 24 and the front skin 51 are spaced apart so as to form between them an air blow-out opening 32 comprising a guide channel, preferably of annular shape. Preferably, a spacer stud 6 has a radial thickness between 1 mm and 8 mm to form a guide channel of calibrated thickness. Preferably, the radial thickness depends on the desired de-icing conditions (temperature, pressure, etc.)

[0077] Advantageously, unlike the first embodiment, there is no need to drill through the front wall 24 of the first module M1, the blow-out opening 32 is here formed at the interface zone during assembly. Mechanical stresses in the front wall 24 of the first module M1 are thereby limited. Such an offset blow-out opening 32 is known to the skilled person as “step down slot”. In this example, the blow-out opening 32 is circumferential.

[0078] With reference to FIG. 8A, the internal wall 21 of the lip 2a comprises a radial discontinuity due to the gap between the front wall 24 and the front skin 51. Alternatively, with reference to FIG. 8C, the downstream end 24a of the front wall 24 is beveled, its radially inner surface converging radially outward along an upstream to downstream direction. Such a bevel is simple to make and significantly limits aerodynamic discontinuities at the interface between the front wall 24 and the front skin 51. Good performance is achieved for a bevel angle θ less than 15° as illustrated in FIG. 8C. Preferably, the radially internal surface is curved to form an aerodynamic profile.

[0079] According to a third embodiment, as illustrated in FIG. 9, the front skin 51 of the second module M2 is curved so as to comprise an end portion 51a facing the front wall 24 of the first module M1 to allow radial attachment and a central portion 51b as an extension of the front wall 24 of the first module M1.

[0080] In this embodiment, the front wall 24 and the front skin 51 have substantially the same shape as in the first embodiment but are radially spaced apart in a manner analogous to the second embodiment, in particular, by spacer studs 6 (not represented in FIG. 9) and is in the form of an annular slot.

[0081] Advantageously, a blow-out opening 33 is formed here at the interface zone during assembly. The blow-out opening 33 comprises a guide channel extending longitudinally between the front wall 24 and the front skin 51 so as to guide the hot air flow. The blow-out opening 33 opens at the interface between the front wall 24 and the front skin 51 which are aligned. Such a buried blow-out opening 33 is known to the skilled person as “buried slot”. In this example, the blow-out opening 33 is circumferential.

[0082] According to one alternative of the invention, with reference to FIG. 10, when the blow-out opening 32, 33 comprises a guide channel formed between the front wall 24 and the front skin 51, a filling member 7 can advantageously be provided in the guide channel so as to act on the hot air flow before it is discharged.

[0083] Preferably, the filling member 7 can comprise elementary channels in order to separate the hot air flow into a plurality of elementary flows so as to promote guidance and allow optimal de-icing. As an example, the filling member 7 comprises a corrugated panel sandwiched between two circumferential panels. Further preferably, the filling member 7 is made of a metallic material.

[0084] According to an alternative of the invention, with reference to FIGS. 11A and 11B, the lip 2a comprises spacer studs 6′ having an aerodynamic profile so as to define an upstream-oriented leading edge and a downstream-oriented trailing edge. Preferably, a spacer stud 6′ is shaped like a drop of water as illustrated in FIGS. 11A and 11B, the cross-section of which increases and then decreases from upstream to downstream. However, it goes without saying that each spacer stud could have a different shape

[0085] The spacer studs 6, 6′ (with an aerodynamic or non-aerodynamic profile) can be mounted as an insert between the front wall 24 and the front skin 51, but can also be made of the material of the front wall 24 or of the front skin 51. Preferably, the spacer studs 6, 6′ are made of the material of the front wall 24 and formed upon making the first module M1.

[0086] By virtue of the invention, a modular design makes it easier to hold and treat the modules M1, M2, since their overall size is limited and can be achieved with simpler and less expensive equipment. Furthermore, the risk of defects is limited because the modules M1, M2 are accessible on each of their faces, which facilitates their inspection. Moreover, a modular assembly allows for various assembly solutions without affecting health of the modules M1, M2.

[0087] In particular, by virtue of the invention, mechanical characteristics of the internal wall 21 are preserved and it is no longer susceptible to deformation. The external wall 22 is also preserved since it is no longer introduced into a soldering furnace. Finally, the second acoustic module M2 can simply be replaced in case of defect.