CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to and incorporates by reference French Patent Application Number 1857967, filed Sep. 5, 2018.

BACKGROUND

1. Field of the Invention

The disclosure generally relates to an air intake structure of an aircraft nacelle and, more specifically, to a nacelle comprising such an air intake structure and an aircraft comprising at least one such nacelle.

2. Description of the Related Art

An aircraft turbine engine comprises a nacelle in which the engine assembly is housed. The nacelle, which has an annular shape, has an air intake structure at the front.

The air intake structure globally comprises an inner face and an outer face in contact with the external air, whereas the inner face delimits a channel which constitutes the fan duct. The function of the air intake structure is notably to ensure the aerodynamic flow of the air, on the one hand towards the fan duct, and on the other hand towards the outside of the nacelle.

The air intake structure conventionally comprises an air intake lip, a front reinforcing frame and an acoustic panel.

The air intake lip has a U-shaped cross section open towards the rear, it forms the outer envelope of the forward part of the air intake structure and it ensures the division of the air between the part which enters into the fan duct and the part which flows around the nacelle.

The front reinforcing frame also has a U-shaped cross section open towards the rear and it is placed inside of and at the rear of the air intake lip. The front reinforcing frame provides the mechanical strength of the front part of the nacelle and helps to preserve its shape and dimensions.

The acoustic panel forms the inner envelope of the nacelle, behind the air intake lip, on the fan duct side. The acoustic panel therefore constitutes a part of the inner face.

The acoustic panel has a structure suitable for attenuating the noise produced by the engine and notably by the fan. This acoustic panel is of the composite sandwich type, and it integrates a cellular core, for example of honeycomb form, between an inner wall and an outer wall. The inner wall delimits the fan duct and extends the air intake lip, whilst 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 the circulation of a hot air flow which provides the de-icing of the air intake lip.

Although such an air intake structure is entirely satisfactory during its use, it is desirable to find a structure which make it possible to increase the range of frequencies attenuated and to increase the de-iced and sound-absorbing surface.

SUMMARY

The present disclosure is embodied as an air intake structure of an aircraft nacelle which may provide a larger de-iced and sound-absorbing surface.

In an exemplary embodiment, an air intake structure for an aircraft nacelle is embodied to delimit a channel and comprising:a lip having a U-shaped cross section oriented towards the rear,a first sound-absorbing panel fixed behind the lip and delimiting the channel, anda second sound-absorbing panel fixed behind the first sound-absorbing panel and delimiting the channel,

where each sound-absorbing panel comprises a cellular core which is fixed between an inner skin oriented towards the channel and pierced with holes oriented towards the channel and an outer skin oriented in the opposite direction, where the inner skin of the first sound-absorbing panel has a thickness greater than the thickness of the inner skin of the second sound-absorbing panel, and

where each of the inner skins comprises a heat source which is embedded in the mass of the said inner skin.

Such an air intake structure thus makes it possible to extend the de-iced and sound-absorbing surface from the front of the air intake lip to the rear of the acoustic panel.

The inner skin of the first sound-absorbing panel may have a thickness of 3 to 6 mm.

The inner skin of the second sound-absorbing panel may have a thickness of 0.6 to 2.1 mm.

Each cellular core may have the form of a honeycomb.

The inner skins of the two sound-absorbing panels may form a one-piece element.

According to an exemplary embodiment, at least one of the heat sources is supplied with electrical energy and the heat source is embedded in an electrical insulator.

According to an exemplary embodiment, at least one of the heat sources may be supplied with electrical energy, and the heat source may integrate a vibrating element.

According to an exemplary embodiment, at least one of the heat sources may be formed by tubes in which a hot fluid flows.

For each heat source, the inner skin may comprise an element having heat conducting characteristics which has one face positioned close to the heat source and one face in contact with the channel.

According to an exemplary embodiment, a nacelle is disclosed comprising, at the front, an air intake structure according to one of the preceding embodiments.

According to an exemplary embodiment, an aircraft is disclosed comprising at least one nacelle according to the preceding embodiments.

