AIRFLOW-STRAIGHTENING STRUCTURE FOR THE NACELLE OF AN AIRCRAFT ENGINE

Abstract

An airflow-straightening structure for an aircraft engine is provided that includes a hoop inside which there are arranged a plurality of flow-straightening vanes bearing a hub of a fan. Also includes is a clevis for connecting to a suspension strut, the clevis being fixed to said hoop. The structure has at least two elements chosen from the group of the hoop, the plurality of vanes, the hub and the clevis, which are formed in one piece, that is to say without any assembly operation. Additionally, at least one of the elements chosen from the group is at least partially formed of a composite material.

Description

FIELD

The present disclosure relates to an airflow-straightening structure for an aircraft engine.

BACKGROUND

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

As is known in itself, and shown in the appended FIG. 1, a nacelle having axis A for a dual-flow (turbojet) engine traditionally comprises an outer structure 1 having an upstream portion 3 forming an air intake, an intermediate portion 5 whereof the inner skin 6 forms a case for the fan 7 of the engine, and a downstream portion 9 that may incorporate thrust reversal means.

This nacelle also includes an inner structure 11 having a fairing 13 for the engine 15.

The outer structure 1 defines, with the inner structure 11, an annular air duct 17, often called “cold air duct,” as opposed to the hot air created by the engine 15.

The fan 7 essentially consists of a propeller provided with blades 19, which are rotatably mounted on a stationary hub 21 connected to the fan case 6 by a plurality of stationary arms 25, which may for example be distributed at 120 degree intervals.

Upstream of these stationary arms are airflow-straightening vanes 23, also called OGV (“Outlet Guide Vanes”), which make it possible to straighten the cold air flow created by the fan 7.

SUMMARY

The present disclosure provides an airflow-straightening structure for an aircraft engine, comprising:

• • a hoop inside which there are arranged a plurality of flow-straightening vanes bearing a hub of a fan, and
  • a clevis for connecting to a suspension strut, said clevis being fixed to said hoop,

the structure being remarkable in that at least two of the elements chosen from the group consisting of said hoop, said plurality of vanes, said hub and said clevis are formed in one piece, that is to say without any assembly operation,

and for the fact that at least one of the elements chosen from the group consisting of said hoop, said plurality of vanes, said hub and said clevis is at least partially formed of composite material.

Having at least two of the aforementioned elements (hoop, vanes, hub, clevis) made in a single piece makes it possible to limit the number of assembly operations to be carried out during assembly of the nacelle, and having at least one of those four elements made from a composite material enables savings in terms of weight.

According to other optional features of this structure according to the invention:

• • all of said elements are made in a single piece and from a composite material: in this way, the ease of assembly and weight reduction are optimized;
  • the hoop incorporates the case of said fan;
  • the hoop incorporates an air intake shroud for the nacelle;
  • the hoop incorporates a thrust reverser cascade edge: these various arrangements make it possible to still further reduce the number of parts.

The present disclosure also relates to a nacelle for an aircraft engine, remarkable in that it comprises an airflow-straightening structure as described above.

Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

FIG. 1 is a longitudinal half-section view of a nacelle and engine assembly of the prior art, described in the preamble of this description;

FIG. 2 is a perspective view of an airflow-straightening structure according to the present disclosure; and

FIG. 3 is a detailed cross-sectional view of an engine equipped with an airflow-straightening structure according to one particular form of the present disclosure, and the associated nacelle portion.

In all of the figures, identical or similar references designate identical or similar members or sets of members.

It will also be noted that a three-axis reference has been provided in these figures showing the X, Y and Z axes. These three axes respectively represent the longitudinal, transverse and vertical directions of the engine when it is installed on an aircraft.

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

FIG. 2 shows that the airflow-straightening structure according to the invention may comprise a plurality of airflow-straightening vanes 23 extending between a radially inner wheel 27 and a radially outer wheel 29, these vanes and wheels thus forming a flow-straightening grid.

The wheel with the larger diameter 29 is designed to be fixed or integrated inside a hoop 31 that is part of the inner skin of the intermediate portion 5 of the outer structure 1 of the engine.

The wheel with the smaller diameter 27 bears the stationary hub 21 on which the fan 7 is rotatably mounted.

Fixed on the upper portion of the hoop 31 is a clevis 33 for suspending the nacelle from a support strut secured to the structure of an aircraft: this clevis makes it possible to connect the nacelle and its associated engine 15 to the aircraft.

In one form, the airflow-straightening vanes 23 and the wheels 27, 29 are formed in a single piece.

Also, the hub 21 on the one hand and the assembly formed by the hoop 31 and the clevis 33 on the other hand are also formed in a single piece.

At least some of said members are made from a composite material, for example by weaving.

Still more preferably, the aforementioned set of members, i.e. the hub 21, the vanes 23, the wheels 27, 29, the hoop 31 and the yoke 33, are formed in a single piece, and from a composite material.

This makes it possible to obtain a multi-functional piece with an overall weight much lower than the set of parts it replaces, and not requiring any assembly operation.

As can be understood from the preceding, the fact that the hub 21 of the fan 7 is borne directly by the airflow-straightening vanes 23 makes it possible to do away with the support arms for that hub, which are present in the nacelles according to the prior art: savings are thus procured in terms of structural simplicity and weight.

FIG. 3 shows a detailed view of the upstream portion of a nacelle and part of the engine which are equipped with an airflow-straightening structure according to the invention, and shows that the hoop 31 can incorporate a fan case 6 and the air intake shroud 35.

As a reminder, the air intake shroud 35 is a substantially cylindrical piece forming the inner skin of the air intake 3, on which sound absorption panels 37 are attached that can typically have a honeycomb structure, so as to form Helmholtz resonators.

The hoop 31 can also incorporate, in the downstream portion thereof, an extension 37 forming a cascade edge, i.e. defining one of the walls of the channel making it possible to guide the cold airflow toward the outside of the nacelle during implementation of the thrust reversal means (not shown).

As will be understood, the additional integration of the fan case 6, the shroud 35 and the cascade edge 37 in the flow-straightening structure according to the invention also allows increased structural simplicity, as well as weight savings when the set of parts is made in a single piece and from a composite material.

Of course, the present disclosure is in no way limited to the embodiments described and shown, which have been provided solely as examples.

Claims

1 An airflow-straightening structure for an aircraft engine, comprising: a hoop inside which there are arranged a plurality of flow-straightening vanes bearing a hub of a fan; anda clevis for connecting to a suspension strut, said clevis being fixed to said hoop, the structure being characterized in that at least two elements chosen from a group consisting of said hoop, said plurality of vanes, said hub and said clevis are formed in one piece, that is to say without any assembly operation,

2. The structure according to claim 1, characterized in that all of said elements are made in a single piece and from a composite material.

3. The structure according to claim 1, characterized in that said hoop incorporates the case of said fan.

4. The structure according to claim 1, characterized in that said hoop incorporates an air intake shroud.

5. The structure according to claim 1, characterized in that said hoop incorporates a thrust reverser cascade edge.

6. A nacelle for an aircraft engine, characterized in that it comprises an airflow-straightening structure according to claim 1.