阅读说明：本技术 具有蜂窝状芯部和除冰系统的吸声面板 (Acoustic panel with honeycomb core and deicing system ) 是由 阿兰·波特 雅克·拉拉内 于 2019-09-04 设计创作，主要内容包括：本发明涉及一种吸声面板,其包括：内蒙皮,该内蒙皮被孔穿过、并且旨在朝向流体在其中流动的通道定向；加热垫,该加热垫由条带构成,该条带在与通道相反的侧上固定至内蒙皮、并且在第一方向上定向,其中,两个相邻的条带彼此间隔开,以便在它们之间留出狭槽；基体,该基体在与所述内蒙皮相反的侧上固定至条带,其中,该基体包括在所述条带侧上的凹槽,该凹槽在与所述第一方向不同的第二方向上延伸,并且其中,该基体具有在两个相继的凹槽之间的肋；蜂窝状芯部,该蜂窝状芯部在与条带相反的侧上固定至基体,以及；外部面板,该外部面板在与基体相反的侧上固定至蜂窝状芯部。这种吸声面板因此能够获得经除冰表面和更好的噪声衰减。(The present invention relates to a sound absorbing panel comprising: an inner skin crossed by a hole and intended to be oriented towards a channel in which the fluid flows; a heating mat consisting of strips fixed to the inner skin on the opposite side to the channel and oriented in a first direction, wherein two adjacent strips are spaced apart from each other so as to leave a slot between them; a base body fixed to the strip on a side opposite to the inner skin, wherein the base body comprises a groove on the strip side, the groove extending in a second direction different from the first direction, and wherein the base body has a rib between two successive grooves; a honeycomb core fixed to the base on a side opposite to the strip, and; an outer panel fixed to the honeycomb core on a side opposite to the base. Such an acoustic panel thus enables a de-iced surface and better noise attenuation to be obtained.)

1. An acoustic panel (28) comprising:

an inner skin (36) crossed by a hole and intended to be oriented towards a channel (26) in which a fluid flows,

-a heating mat (48, 448) constituted by strips (50) fixed to the inner skin (36) on the opposite side to the channels (26) and oriented in a first direction (52), wherein two adjacent strips (50) are spaced apart from each other so as to leave a slot (51) between them,

-a basic body (53) which is fixed to the strip (50) on the side opposite to the inner skin (36), wherein the basic body (53) comprises grooves (54) on the side of the strip (50) which extend in a second direction (56) different from the first direction (52), and wherein the basic body (53) has a rib (58) between two successive grooves (54),

-a honeycomb core (32) fixed to the base body (53) on the side opposite to the strip (50), and

-an outer panel (40) fixed to the honeycomb core (32) on the opposite side to the base (53).

2. The sound absorbing panel (28) according to claim 1, wherein the strips (50) are integral with one another.

3. The sound absorbing panel (28) according to one of claims 1 and 2, wherein the first direction (52) is perpendicular to the second direction (56).

4. The sound absorbing panel (28) according to one of claims 1 to 3, characterized in that the overall thickness of the matrix (53) at the level of the ribs (58) is at least 4 mm.

5. The sound absorbing panel (28) according to one of claims 1 to 4, wherein each strip (50) comprises an electrical resistance element (60) and an electrical insulator (62) in which the electrical resistance element (60) is embedded, the electrical resistance element generating heat when an electrical current passes through it.

6. The sound absorbing panel (28) according to one of claims 1 to 4, wherein each strip (50) is crossed by a pipe (64) in which the heated heat transfer fluid flows.

7. The sound absorbing panel (28) according to one of the preceding claims, wherein the inner skin (36) is made of a heat conductive material.

8. An air intake structure (22) for a nacelle (19) of an aircraft (10), the air intake structure (22) defining a channel (26) and comprising a lip (24) having a U-shaped cross-section oriented towards the rear and a first sound-absorbing panel (28) according to one of the preceding claims, fixed behind the lip (24) and defining the channel (26).

9. Air intake structure (22) according to the preceding claim, comprising a second sound absorbing panel (30) fixed behind the first sound absorbing panel (28), and comprising a honeycomb core (34) fixed between an inner skin (38) perforated and oriented towards the channels (26) and an outer panel (42) oriented in the opposite direction.

10. A nacelle (19) comprising an air intake structure (22) at the front according to one of the preceding claims.

11. An aircraft (10) comprising at least one nacelle according to the preceding claim.

Technical Field

The present invention relates to a sound-absorbing panel with a honeycomb core and a deicing system, an air intake structure of an aircraft nacelle comprising such a sound-absorbing panel, a nacelle comprising such an air intake structure, and an aircraft comprising at least one such nacelle.

Background

Acoustic panels are used in many technical fields, in particular in the aeronautics field.

An aircraft turbine engine includes a nacelle in which an engine assembly is housed. The nacelle having an annular shape has an air inlet structure at the front.

The air intake structure generally comprises an inner face and an outer face in contact with the outside air, while the inner face defines a channel constituting a fan duct. The function of the air intake structure is mainly to ensure an aerodynamic flow of air towards the fan duct on the one hand and towards the outside of the nacelle on the other hand.

The air scoop structure conventionally includes an air scoop lip, a front reinforcing frame, and an acoustic panel.

The air intake lip, which has a U-shaped cross-section open towards the rear, forms an outer envelope of the forward portion of the air intake structure and ensures the distribution of air between the portion entering the fan duct and the portion flowing around the nacelle.

The front reinforcing frame also has a U-shaped cross-section open towards the rear, and is placed inside the air intake lip and at the rear. The forward reinforcing frame provides mechanical strength to the forward portion of the nacelle and helps to maintain its shape and size.

The acoustic panel forms an inner cladding of the nacelle on the fan duct side, behind the air intake lip. Thus, the acoustic panel constitutes a part of the interior face.

The acoustic panel has a structure suitable for attenuating the noise generated by the engine and in particular by the fan. Such acoustic panels are of the composite sandwich type and incorporate a honeycomb core between an inner wall and an outer wall. The inner wall defines the fan duct and extends the air intake lip, while the outer wall is inside the air intake structure but oriented towards the outside of the nacelle.

The volume between the air intake lip and the front reinforcing frame allows circulation of a hot air flow which ensures deicing of the air intake lip.

While such air intake structures are entirely satisfactory during their use, it is desirable to find a structure that enables an increase in the attenuation frequency range and an increase in the de-icing and sound absorbing surfaces.

Disclosure of Invention

It is an object of the present invention to propose a sound absorbing panel that provides better noise attenuation and de-icing.

To this end, a sound absorbing panel is proposed, comprising:

an inner skin crossed by a hole and intended to be oriented towards a channel in which a fluid flows,

-a heating mat consisting of strips fixed to the inner skin on the opposite side to the channel and oriented in a first direction, wherein two adjacent strips are spaced apart from each other so as to leave a slot between them,

-a base body fixed to the strip on the side opposite the inner skin, wherein the base body comprises grooves on the strip side, which grooves extend in a second direction different from the first direction, and wherein the base body has a rib between two successive grooves,

-a honeycomb core fixed to the base on the side opposite to the strip, an

-an outer panel fixed to the honeycomb core on a side opposite to the base.

Such an acoustic panel thus enables a de-iced surface and better noise attenuation to be obtained.

Advantageously, said strips are integral with each other.

Advantageously, the first direction is perpendicular to the second direction.

Advantageously, the overall thickness of the base body at the level of the ribs is at least 4 mm.

Advantageously, each strip comprises a resistive element and an electrical insulator in which the resistive element is embedded, the resistive element generating heat when an electrical current passes through it.

Advantageously, each strip is crossed by a tube in which the heated heat transfer fluid flows.

Advantageously, the inner skin is made of a heat-conducting material.

The invention also proposes an air intake structure for a nacelle of an aircraft, which defines a channel and comprises a lip having a U-shaped section oriented towards the rear and a first sound-absorbing panel according to one of the preceding variants, which is fixed behind the lip and defines the channel.

Advantageously, the air intake structure comprises a second sound-absorbing panel fixed behind the first one, and a honeycomb core fixed between an inner skin perforated with holes and oriented towards the channels, and an outer panel oriented in the opposite direction.

The invention also proposes a nacelle comprising an air intake structure according to one of the preceding variants at the front.

The invention also proposes an aircraft comprising at least one nacelle according to the previous variant.

Drawings

The above-mentioned and other features of the present invention will become more apparent upon reading the following description of exemplary embodiments, which is given with reference to the accompanying drawings, in which:

figure 1 shows a side view of an aircraft according to the invention,

figure 2 is a cross-sectional side view of an air intake structure according to the present invention,

FIG. 3 is an exploded perspective view of a sound absorbing panel according to the present invention, and

figure 4 is a perspective view of a heating mat according to a variant embodiment.

Detailed Description

In the following description, position-related terms are used with reference to an aircraft in a forward-moving position, i.e. an aircraft as shown in fig. 1.

FIG. 1 illustrates an aircraft 10 including at least one turbine engine 20.

Throughout the following description, by convention, the direction X corresponds to a longitudinal direction of the turbine engine 20, this direction being parallel to the longitudinal axis X of the turbine engine 20. On the other hand, direction Y corresponds to a direction oriented laterally with respect to turbine engine 20, and direction Z corresponds to a vertical or height direction, with these three directions X, Y, Z being orthogonal with respect to each other.

The turbine engine 20 conventionally includes a nacelle 19 including an air inlet structure 22 at a forward portion that includes lips that define the interior and exterior of the nacelle 19. The lip extends inwardly through an inner wall that extends around a channel that directs air toward an engine component including a fan or the like.

Fig. 2 shows an air inlet structure 22 comprising a lip 24 having a U-shaped cross-section located towards the rear and having a generally annular shape. The air intake structure 22 defines a passage 26 that directs air toward the engine assembly, and in particular toward the fan.

The lip 24 defines an exterior 25 and an interior 26 of the nacelle 19. The interior 26 corresponds to the channel 26.

In the embodiment of the invention described herein, the air intake structure 22 includes first and second sound absorbing panels 28, 30 surrounding the channel 26, which define the channel 26. A first sound absorbing panel 28 is secured behind the lip 24 up to a second sound absorbing panel 30. The second sound absorbing panel 30 is fixed behind the first sound absorbing panel 28.

In the case of the present invention, the reinforcing frame has been eliminated and the air intake structure 22 of the present invention is reinforced by the presence of the first sound absorbing panel 28, which also has structural capabilities.

The second sound absorbing panel 30 includes a honeycomb core 34 secured between outer panels 42 oriented in opposite directions of an inner skin 38 oriented toward the channels 26. The inner skin 38 is perforated with holes that allow sound waves to propagate into the core 34 to be attenuated therein.

The second acoustic panel 30 is arranged to attenuate high frequencies in the range between 1000Hz and 4000 Hz. For this purpose, the inner skin 38 of the second sound-absorbing panel 30 has a thickness of the order of 0.9mm to 2mm, and the holes 46 therefore also have a length of at least 0.9mm to 2 mm.

Fig. 3 shows an exploded view of the first sound-absorbing panel 28.

The first sound absorbing panel 28 includes an inner skin 36 that is oriented toward the channel 26 and is penetrated by holes that allow sound waves to propagate through the inner skin 36. Generally, the inner skin 36 is intended to be oriented toward the channel 26 in which the fluid flows. The inner skin 36 may, for example, be of the porous element type (e.g., a porous fabric or mesh).

The first sound-absorbing panel 28 also comprises a heating mat 48, constituted by strips 50, which are fixed to the inner skin 36 on the side opposite to the channels 26. All of the strips 50 are oriented in a first direction 52. Two adjacent strips 50 are spaced apart from each other so as to leave a slot 51 between them. The holes of the inner skin 36 open into these slots 51, which allow the sound waves to advance.

The heating mat 48 makes it possible to de-ice the face of the inner skin 36 that is in the channel 26.

The first sound-absorbing panel 28 also comprises a matrix 53 which is fixed to the strip 50 on the side opposite to the inner skin 36. The base 53 comprises grooves 54 on the side of the strip 50, which grooves extend in a second direction 56 different from the first direction 52, in particular perpendicular to the first direction 52. The base body 53 thus has a rib 58 parallel to the second direction 56 between two successive recesses 54. The base 53 is thus supported to the strip 50 by the ribs 58.

The substrate 53 is also penetrated by holes allowing the sound waves to advance.

The overall thickness of the base 53 at the level of the ribs 58 is of the order of 0.9mm to 5mm, and the depth of the holes through the ribs 58 is therefore also equal to 0.9mm to 5 mm. The thickness of the base 53 at the level of the recess 54 is for example of the order of 0.3 to 0.9mm, and the hole through the base therefore also has a depth of 0.3 to 0.9 mm. According to a particular embodiment, the overall thickness of base 53 at the level of ribs 58 is at least 4 mm.

The first sound-absorbing panel 28 also comprises a honeycomb core 32 fixed to the base 53 on the side opposite to the strips 50.

The first sound-absorbing panel 28 also includes an outer panel 40 that is fixed to the honeycomb core 32 on the side opposite the base 53.

This structure allows for better noise attenuation because the sound waves will propagate through the inner skin 36, the slots 51, the grooves 54, the matrix 53, and finally through the honeycomb core 32. The continuous holes with smaller diameter and larger space (slots 51 and grooves 54) form variations that slow down the sound waves and thus attenuate the noise.

Furthermore, the presence of the slot 51 and the groove 54 makes it possible to keep the hole open even after assembly and therefore to increase the percentage of open surface.

When the thickness is at least 4mm, the base 53 at the level of the ribs 58 makes it possible to attenuate low frequencies ranging between 300Hz and 600 Hz. The volume of the cells of the honeycomb core 32 in which the pores of the matrix 53 occur and the depth of these pores make it possible to select the frequency to be attenuated. For example, for a hole depth of 4mm and a cell height of 40mm, frequencies around 500Hz are attenuated.

Thus, by using a sound absorbing panel based on two different technologies, the attenuation of sound waves is greater and the frequency range of the attenuation is also expanded compared to the prior art.

The face of the inner skin 36 of the first sound-absorbing panel 28 oriented towards the channel 26 is flush with the face of the inner skin 38 of the second sound-absorbing panel 30 oriented towards the channel 26 in order to create an aerodynamic surface.

The inner skin 38 of the second sound absorbing panel 30 also preferably includes a heat source embedded in the mass of the inner skin 38.

Each strip 50 includes, for example, a resistive element 60 that generates heat when an electrical current is passed through it and an electrical insulator 62 in which the resistive element 60 is embedded.

Each strip 50 may be traversed by a tube 64 in which a heat transfer fluid (for example hot air) flows.

To facilitate the transfer of heat, the inner skin 36 is made of a thermally conductive material.

Thermal insulation may be arranged on certain sides of the strip 50 in order to limit heat propagation in certain directions. It is also possible to arrange heat conductors on certain sides of the strip 50 in order to facilitate the heat propagation in certain directions.

Figure 4 illustrates a heating pad 448 in accordance with certain embodiments, wherein to facilitate operation of the heating pad 448, the bands 50 are integral with one another, such as by a bridge 66 passing through a slot 51. The heating pad 448 thus becomes a hollowed-out sheet.