MODULE FOR SOUND WAVE DAMPING AND HEAT EXCHANGE

Description

TECHNICAL FIELD

[0001] The present invention relates to a module ensuring attenuation of acoustic waves generated by the flow of a first fluid and also allowing heat exchange between this first fluid and a second fluid, a method of making such a module, an aircraft nacelle comprising such modules, as well as an aircraft having such a module. PREVIOUS STATE OF THE ART

[0002] An aircraft turbomachine, particularly a turbofan, has an air intake at the front through which fresh air enters the turbomachine. This air intake is enclosed by walls that channel the airflow. Some of this air is used for heat exchange with the aircraft's fluids. Heat exchangers are integrated into the walls for this purpose.

[0003] The interior of the duct is also lined with structures that attenuate the acoustic waves generated by the airflow within the duct, thus reducing the noise of the turbomachine. These structures typically include a perforated wall facing inward, behind which is a series of cavities, often honeycomb-shaped. These cavities form quarter-wave resonators that attenuate a specific frequency.

[0004] Implementing heat exchangers at the wall level of the channel reduces the space allocated to acoustic structures, which can lead to an increase in turbomachine noise, and it is therefore necessary to implement a structure that ensures both acoustic wave attenuation and heat exchange without limiting the attenuation surface.

[0005] Documents US-A-2011 / 126544 and FR-A-2 960 334 disclose prior art systems. DESCRIPTION OF THE INVENTION

[0006] An object of the present invention is to provide a module ensuring attenuation of acoustic waves generated by the flow of a first fluid and a heat exchange between this first fluid and a second fluid.

[0007] To this end, a module is proposed that provides acoustic attenuation of a flow of a first fluid and heat exchange between the first fluid and a second fluid, the module comprising: a first wall which is perforated, along which the said first fluid flows, a second wall, an alveolar structure delimiting alveoli extending from the second wall towards the first wall, and having a first end integral with the second wall and a second end, and a heat exchanger in which the second fluid circulates, The module is characterized in that the first wall has a cutout, in that the module includes a recess in the honeycomb structure, delimited between a floor and a ceiling that are perforated, where the ceiling closes the cutout, where the floor extends at a distance from the ceiling, where, outside the recess, the second end of the honeycomb structure is integral with the first wall, and where, at the level of the recess, the second end of the honeycomb structure is integral with the floor, and in that the heat exchanger is fixed inside the recess between the floor and the ceiling. Such a module provides acoustic wave attenuation and heat exchange without limiting the attenuation surface area.

[0008] Advantageously, the heat exchanger includes pipes that snake through the recess, a supply pipe that channels the second fluid from its area of ​​use to the pipes and an extraction pipe that channels the second fluid from the pipes to its area of ​​use.

[0009] Advantageously, the supply and exhaust pipes pass through the honeycomb structure, the floor, and the second wall via a bore. Advantageously, the module includes, for each supply and exhaust pipe, a seal that is positioned around said pipe and closes the bore at the level of the floor and the second wall.

[0010] Advantageously, the module includes a lip that is fixed around the floor and extends from the floor to the ceiling.

[0011] Advantageously, the module includes foam between the rim and the honeycomb structure. In one particular embodiment, the module has a gap between the rim and the ceiling along its perimeter, and sealant is applied to close this gap. In another particular embodiment, the ceiling extends over the rim with a smooth finish.

[0012] The invention also proposes a method for producing a module according to the previous variant, where said method comprises: a first supply stage during which the honeycomb structure is supplied, a shaping stage during which the honeycomb structure thus supplied is shaped to create the recess, a second supply stage during which a shell including the perforated floor is supplied, a first fixing stage during which the shell is fixed in the recess, a third supply stage during which the first perforated wall, cut according to the cutout, is supplied, a fourth supply stage during which the second wall is supplied, a second fixing stage during which the first and second walls are fixed on either side of the honeycomb structure, a fifth supply stage during which the heat exchanger is supplied, a third fixing stage during which the heat exchanger is fixed in the recess,a sixth supply stage during which the perforated ceiling is supplied, and a fourth fixing stage during which the ceiling is fixed above the heat exchanger to close the recess.

[0013] The invention also proposes an aircraft nacelle comprising an external wall and an internal wall delimiting an air stream and where the external wall and / or the internal wall carry at least one module according to one of the preceding variants and where the first wall is oriented towards the inside of the stream. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The features of the invention mentioned above, as well as others, will become clearer upon reading the following description of an exemplary embodiment, said description being made in relation to the accompanying drawings, among which: [ Fig. 1 ] is a side view of an aircraft according to the invention, [ Fig. 2 ] is a perspective view of a module according to the invention, and [ Fig. 3 [ ] is a cross-sectional view at the level of a pipe passing through a honeycomb structure of the module according to the invention, DETAILED EXPLANATION OF IMPLEMENTATION METHODS

[0015] There Fig. 1 Figure 10 shows an aircraft with a nacelle 20 containing a turbomachine. Inside the nacelle 20 is an air duct that passes through both the nacelle and the turbomachine. The air duct is thus delimited by an outer wall (also called an OFS, "outer fixed structure") and an inner wall (also called an IFS, "internal fixed structure") of the nacelle 20.

[0016] There Fig. 2 shows a module 100 according to the invention which ensures, on the one hand, acoustic attenuation of noises generated by a first fluid flowing along this module 100 and, on the other hand, heat exchange between the first fluid and a second fluid circulating inside this module 100.

[0017] Such a module 100 can be installed on the outer and / or inner wall of the nacelle 20 or in another environment, provided it is necessary to attenuate the noise generated by the flow of a first fluid and to achieve heat exchange between the first fluid and a second fluid. Such a module 100 covers the surface of the wall to which it is attached, and there may be several such modules 100 supported by said wall. In the embodiment of the invention presented in the Fig. 2 The module takes the form of a paving stone, but it can take another form to adapt to the geometry of the wall on which it is fixed.

[0018] Module 100 has a first wall 102 (cut on the left) which is perforated and therefore crossed by holes 103a and a second wall 104 at a distance and, here, parallel to the first wall 102.

[0019] The first wall 102 is in contact with the first fluid, in particular a gas, which flows in the vein along said first wall 102 and which is represented here by arrow F.

[0020] The second wall 104 is solid and fixed to the wall that delimits the vein.

[0021] The module 100 also includes a plurality of intermediate walls 106 which extend from the second wall 104 to the first wall 102. In the embodiment of the invention presented here, the intermediate walls 106 extend perpendicularly to the first wall 102 and to the second wall 104.

[0022] The intermediate walls 106 are arranged and joined together to form cells 108, which here have a hexagonal cross-section and extend from the second wall 104 to the first wall 102. Each cell 108 has a first end joined to the second wall 104 and a second end.

[0023] The intermediate walls 106 together define an alveolar structure 109 which has a first end attached to the second wall 104 and a second end.

[0024] The first wall 102 has a cutout 152, which here is rectangular in shape.

[0025] Module 100 includes a recess 150 made in the honeycomb structure 109 and delimited between a floor 154 and a ceiling 156.

[0026] Ceiling 156 (cut here on the left) closes off cutout 152 and is also perforated and therefore pierced by holes 103b. To limit aerodynamic impacts, ceiling 156 and the first wall 102 are generally aligned.

[0027] Floor 154 extends at a distance from ceiling 156, and here parallel to it, and is recessed into module 100 towards the second wall 104. Floor 154 here covers roughly the same area as ceiling 156. Floor 154 is also perforated and therefore crossed by holes 103c.

[0028] Apart from the recess 150, the second end of each cell 108 and therefore the second end of the alveolar structure 109 are fixed to the first wall 102 and at the level of the recess 150, the second end of each cell 108 and therefore the second end of the alveolar structure 109 are fixed to the floor 154. The intermediate walls 106 are therefore shorter at the level of the recess 150 than outside the recess 150.

[0029] In the case of the first fluid, preferably a gas, flowing through the channel, the first wall 102 is oriented towards the interior of the channel. The first fluid, which here is air, flows along the first wall 102, and the holes 103a-c allow some of the air to penetrate the cells 108, thus attenuating the acoustic waves generated by the airflow. Depending on its position, the air passes through the first wall 102 or the ceiling 156 and the floor 154 before reaching a cell 108.

[0030] The fact that the 108 cells are joined together even under the 150 recess ensures that the 100 module constitutes a structural element.

[0031] Module 100 also includes a heat exchanger 180, which is fixed inside the recess 150 between the floor 154 and the ceiling 156. A second fluid, which could be, for example, turbomachine oil, circulates through this exchanger and is cooled by heat exchange with the first fluid via the heat exchanger 180. The heat exchanger 180 is secured, for example, by means of inserts embedded in the honeycomb structure 109 and clamping screws that engage with these inserts.

[0032] The heat exchanger 180 here includes pipes 182 which snake in the recess 150.

[0033] To ensure the circulation of the second fluid in the pipes 182, the heat exchanger 180 includes a supply pipe 184 which channels the second fluid from its area of ​​use to the pipes 182 and an extraction pipe 186 which channels the second fluid from the pipes 182 to its area of ​​use.

[0034] In the embodiment of the invention presented on the Fig. 2 , the supply pipe 184 and the extraction pipe 186 pass through the alveolar structure 109, the second wall 104 and the floor 154 through bores provided for this purpose.

[0035] The heat exchanger 180 is thus integrated into the module 100 without reducing the surface area associated with acoustic attenuation while ensuring the rigidity of the module due to the presence of the alveoli 108 over the entire surface of the module 100.

[0036] In the embodiment of the invention presented to the Fig. 2 , there is only one 150 recess and one 180 heat exchanger, but it is possible to have several 150 recesses made inside the same 100 module and to have one 180 heat exchanger per 150 recess.

[0037] A method for manufacturing such a module 100 includes, for example, a first supply step during which the honeycomb structure 109 is supplied. The manufacturing process continues with a shaping step during which the supplied honeycomb structure 109 is shaped to create the recess 150 and any bores made in the floor 154 for the passage of the supply pipe 184 and the exhaust pipe 186, and the fixing inserts for the heat exchanger 180. The honeycomb structure 109 is made, for example, of metal (aluminum and its alloys, titanium and its alloys) or of synthetic fibers (Nomex®, Kevlar®). Before the bores are made, a resin can be injected into the cells where the bores will be made to facilitate machining.

[0038] The process includes a second supply step during which a shell is provided. The shell comprises the floor 154, which is perforated and drilled with any necessary bores for the passage of the supply pipe 184 and the exhaust pipe 186, and with inserts for fixing the heat exchanger 180. The shell may also include guides for the subsequent installation of the heat exchanger 180.

[0039] In the embodiment of the invention presented to the Fig. 2 , the hull also includes a rim 158 which is fixed around the floor 154 and extends from the floor 154 to the ceiling 156 so as to delimit the recess 150 laterally.

[0040] The hull is made, for example, of metal (aluminum and its alloys, titanium and its alloys) or of composite materials.

[0041] The process then includes a first fixing step during which the shell is fixed in the recess 150. The shell is fixed, for example, by bonding the floor 154 to the honeycomb structure 109 using a cross-linked adhesive. The adhesive can be cross-linked directly onto the shell or onto the honeycomb structure 109.

[0042] To absorb dimensional tolerances and expansions between the shell and the alveolar structure 109, intumescent adhesive which expands during polymerization is injected between the rim 158 and the alveolar structure 109.

[0043] Optionally, a perforated sheet 160 providing thermal protection is fixed between the honeycomb structure 109 and the floor 154. The perforated sheet 160 is, for example, a carbon sheet.

[0044] The process includes a third supply step during which the first perforated wall 102, cut according to the cutout 152, is supplied. The first wall 102 is made, for example, of metal (aluminum and its alloys, titanium and its alloys) or of composite materials.

[0045] The process includes a fourth supply step during which the second wall 104 is supplied. The second wall 104 is made, for example, of metal (aluminum and its alloys, titanium and its alloys, steel and its alloys) or of composite materials.

[0046] The process then includes a second fixing step during which the first wall 102 and the second wall 104 are fixed, for example by gluing, on either side of the honeycomb structure 109. The first wall 102 is fixed on the side of the recess 150 by aligning the cut 152 with the recess 150 and the second wall 104 is fixed on the opposite side of the recess 150.

[0047] The process includes a fifth supply step during which the exchanger 180 is supplied and a third fixing step during which the exchanger 180 is fixed in the recess 150 possibly by passing the honeycomb structure 109 through the supply pipe 184 and the extraction pipe 186.

[0048] The process includes a sixth supply step during which the perforated ceiling 156 is supplied and a fourth fixing step during which the ceiling 156 is fixed above the exchanger 180 to close the recess 150.

[0049] A thermal protection may optionally be fixed against the second wall 104.

[0050] There Fig. 3 shows an example of an arrangement at the supply pipe 184 but a similar arrangement can be made for the extraction pipe 186.

[0051] A bore 302 is made through the alveolar structure 109 as well as the floor 154 and the second wall 104 and the supply pipe 184 is housed in the bore 302.

[0052] In the case where a thermal protection is fixed against the second wall 104, the bore 302 also passes through the thermal protection.

[0053] To ensure sealing at the floor 154 and the second wall 104, the module includes a seal 304a-b which is positioned around the supply pipe 184 and closes the bore 302 at the floor 154 and respectively at the second wall 104. Each seal 304a-b is made for example of silicone reinforced if necessary with ceramics and glass fibers.

[0054] In one particular embodiment, the extent of the ceiling 156 is smaller than the extent of the rim 158 of the shell. Module 100 then exhibits a gap along the periphery of the ceiling 156, between the rim 158 and the ceiling 156. To close this gap, a sealant is applied to fill and waterproof it. This sealant also absorbs geometric variations due to thermal expansion.

[0055] According to another particular embodiment, the extent of the ceiling 156 is greater than the extent of the rim 158 of the hull, and the ceiling 156 then extends over the rim 158 with a seam to limit the aerodynamic impact. The seam consists of filling the vertical gap between the ceiling 156 and the rim 158 with a double-folded surface that is flush with both the ceiling 156 and the rim 158 and which is made, for example, with a sealant.

[0056] Any other shape that reduces aerodynamic disturbances can be used, such as a chamfer.

[0057] The ceiling 156 is secured, for example, using clamping screws that are screwed through the ceiling 156 into pre-drilled holes. Advantageously, these holes are oblong and oriented at different angles to accommodate the geometric variations of the ceiling 156 due to thermal expansion.

Claims

1. Module (100) ensuring an acoustic attenuation of a flow of a first fluid and a heat exchange between the first fluid and a second fluid, the module (100) comprising: - a first wall (102) which is perforated, along which said first fluid flows, - a second wall (104), - a cellular structure (109) delimiting cells (108) which extend from the second wall (104) to the first wall (102), and having a first end secured to the second wall (104) and a second end, and - a heat exchanger (180) in which the second fluid flows, the module (100) being characterized in that the first wall (102) has a cutout (152), in that the module (100) comprises a recess (150) provided in the cellular structure (109) and delimited between a bottom (154) and a top (156) which are perforated, wherein the top (156) closes off the cutout (152), wherein the bottom (154) extends at a distance from the top (156), wherein, outside the recess (150), the second end of the cellular structure (109) is secured to the first wall (102) and wherein, at the recess (150), the second end of the cellular structure (109) is secured to the bottom (154), and in that the heat exchanger (180) is fixed inside the recess (150) between the bottom (154) and the top (156).

2. Module (100) according to Claim 1, characterized in that the heat exchanger (180) comprises pipes (182) which meander through the recess (150), a supply pipe (184) which channels the second fluid from its zone of use as far as the pipes (182), and an extraction pipe (186) which channels the second fluid from the pipes (182) as far as its zone of use.

3. Module (100) according to Claim 2, characterized in that the supply pipe (184) and the extraction pipe (186) pass through the cellular structure (109), the bottom (154) and the second wall (104) through a bore (302).

4. Module (100) according to Claim 3, characterized in that it comprises, for each supply pipe (184) and extraction pipe (186), a seal (304a-b) which is positioned around said pipe (184, 186) and which closes off the bore (302) at the bottom (154) and at the second wall (104).

5. Module (100) according to one of Claims 1 to 4, characterized in that it comprises an edge (158) which is fixed around the bottom (154) and which extends from the bottom (154) as far as the top (156).

6. Module (100) according to Claim 5, characterized in that it comprises foam between the edge (158) and the cellular structure (109).

7. Module (100) according to either of Claims 5 and 6, characterized in that it has, along the periphery of the top (156), a gap between the edge (158) and the top (156), and in that a mastic is deposited so as to close off the gap.

8. Module (100) according to either of Claims 5 and 6, characterized in that the top (156) overlaps the edge (158) with formation of a joggle.

9. Method for producing a module (100) according to Claim 1, wherein said method comprises: - a first provision step during which the cellular structure (109) is provided, - a shaping step during which the cellular structure (109) thus provided is shaped so as to produce the recess (150), - a second provision step during which a shell comprising the perforated bottom (154) is provided, - a first fixing step during which the shell is fixed in the recess (150), - a third provision step during which the first wall (102) which is perforated and cut according to the cutout (152) is provided, - a fourth provision step during which the second wall (104) is provided, - a second fixing step during which the first wall (102) and the second wall (104) are fixed on either side of the cellular structure (109), - a fifth provision step during which the exchanger (180) is provided, - a third fixing step during which the exchanger (180) is fixed in the recess (150), - a sixth provision step during which the perforated top (156) is provided, and - a fourth fixing step during which the top (156) is fixed above the exchanger (180) so as to close off the recess (150).

10. Nacelle (20) of an aircraft (10) comprising an external wall and an internal wall delimiting an air duct and wherein the external wall and / or the internal wall bear at least one module (100) according to one of Claims 1 to 8 and wherein the first wall (102) is oriented towards the inside of the duct.