AIR INLET STRUCTURE FOR TURBOJET ENGINE NACELLE

The present disclosure relates to an air inlet structure for a turbojet engine nacelle. The air inlet structure has a stationary internal wall to be attached to one element of a mid-section of the nacelle, and a longitudinal external wall extended by an air inlet lip connected to the stationary internal wall. In particular, one portion forming the air inlet lip is provided with depressurizing openings for a part of the air inlet lip.

DETAILED DESCRIPTION

The nacelle generally has a substantially tubular structure comprising an air inlet upstream from the engine (FIG. 1), a midsection intended to surround a fan of the turbojet engine, and a downstream section housing thrust reverser means and intended to surround the combustion chamber of the turbojet engine, and generally ends with a jet nozzle, the outlet of which is situated downstream from the turbojet engine.

FIG. 1shows a longitudinal cross-sectional view of an air inlet structure1according to the prior art.

This air inlet structure1is situated upstream from the midsection2of the nacelle and comprises an air inlet lip3on the one hand, suitable for allowing an optimal capture toward the turbojet engine of the air necessary for the supply thereof, and a downstream structure4on the other hand, on which the lip is attached and intended to channel the air suitably toward the blades of the fan.

More specifically, the air inlet structure1generally has a substantially annular downstream structure4comprising an external wall40ensuring the outer aerodynamic continuity of the nacelle and an internal wall41ensuring the inner aerodynamic continuity of the nacelle.

The air inlet lip3provides the upstream junction between these two walls40,41.

The internal wall41is generally attached to a fan case20belonging to the midsection2and with which it forms a stationary structure.

The external wall40is generally attached to an external wall21of the midsection, with which it ensures the outer aerodynamic continuity.

It should also be specified that the air inlet lip3is generally separated from the downstream part40of the air inlet lip1by a partition5contributing to the strength of the assembly and defining, with the lip3, a compartment3ainside said lip3.

Frequently, the external wall40may be attached thereto removably so as to allow access to the inside of the air inlet structure1, in particular to access internal equipment such as a deicing system of the air inlet1and the lip3.

In the case of so-called laminar nacelles, the air inlet lip3is an integral part of the external wall40, which extends so as to form a single panel generally translatably mounted toward the front of the nacelle.

As shown diagrammatically inFIG. 2, during operation, the air inlet lip3undergoes a forward pressure load (bend) which tends to deform the air inlet lip3, which must therefore have a certain mechanical strength, generally by providing a sufficient lip thickness3.

The wall5is rigidly fixed in51with the internal wall41. At a zone50, if the external wall40is mounted translatable toward the front in the axis of the engine, this junction may be embodied by a single joint. If the external wall40opens, this junction is then rigid, for example using fasteners.

According to the present disclosure, these pressure load forces are compensated by depressurizing the air inlet lip3, and more particularly the compartment3a,if applicable.

A first form of the present disclosure is shown inFIG. 4. In this form, an air inlet structure100, which is similar to the air inlet structure1, is equipped with depressurizing means for the compartment3aof the air inlet lip3assuming the form of openings30formed in the wall of the air inlet lip.

Advantageously, these openings30are situated on an internal face of the air inlet structure, near the internal wall41and its junction with said air inlet lip3.

Also advantageously, the openings30are positioned along a substantially peripheral line of the air inlet structure.

Thus, due to the flow of the air suctioned by the fan through the nacelle, the pressure of the air at the upstream level of the air inlet is extremely reduced. Owing to the presence of openings30, the air present inside the compartment3aof the air inlet lip3is suctioned by the flow of air. This results in a pressure drop inside said compartment3a.

FIGS. 4 to 6show different forms of the openings30making it possible to depressurize the compartment3aof the air inlet lip3.

The openings30may in particular be circular (FIG. 4) or oblong (FIG. 5).

They may also be made at a contact and bearing line between the air inlet lip3and the internal wall41, in particular in the form of separations formed in said contact line.

It is additionally possible to provide for the use of caps on the openings30making it possible to improve the air flows and attenuate the aerodynamic disruptions due to the openings.

FIG. 7shows a second form of the present disclosure.FIG. 7shows an air inlet structure200that differs from the air structure100in that the means for depressurizing the air inlet lip3compartment3acomprise an electric pump60, having a suction duct61emerging in the compartment3aof the air inlet lip3and a delivery duct for delivering the suctioned air62. The delivery duct emerges in a downstream part of the air inlet200. It is possible to provide that this duct62for example emerges in the external wall40, in the internal wall41near the fan, or still further downstream from the fan and the compressor.

Although the present disclosure has been described with one particular example form, it is of course in no way limited thereto and encompasses all technical equivalents of the described means as well as combinations thereof if they are within the scope of the present disclosure.