Varying wall thickness air inlet and associated nacelle

Abstract

The invention relates to an air inlet with varying wall thickness and an associated nacelle. The air inlet makes it possible to avoid the presence of stiffeners and front frames. The air inlet according to the invention comprises a lip (18), which extends on the outer side by at least one outer panel (20), which extends on the inner side by at least one inner panel (22), the wall (24) of the air inlet having a thickness of value e. The thickness of the wall (24) of the air inlet varies longitudinally and comprises a front region (Z2) at the longitudinal front end, the value e2 of the thickness of the front region being greater than the thickness e. In this way, the thickness of the air inlet is optimized according to the need of the region involved. The invention also relates to a nacelle and a propulsion assembly provided with such an air inlet.

Description

Technical Field

[0001] The present invention relates to an air inlet for an aircraft propulsion assembly, a nacelle including such an air inlet, and a propulsion assembly including such a nacelle. Background Technology

[0002] The aircraft is propelled by a propulsion assembly that includes a turbojet engine surrounded by a nacelle. In most propulsion assemblies, the nacelle comprises, from front to back, a first section P1 (called the air intake) upstream of the aerodynamic flow and a second section P2 (called the main section) that forms the remainder of the nacelle. The first section's function is to capture and direct airflow to ensure that it flows to the turbojet engine's fan.

[0003] Patent FR 3099750, filed by Airbus Operations SAS, describes air intake P1, for example... Figure 1 The air intake shown is an intake P1. The intake P1 includes an intake lip 1, which is positioned at the front end to capture the air required for engine supply. An inner panel 3 extends the lip inside the nacelle. An outer panel 4 extends the lip outside the nacelle. The intake P1 typically includes structural elements such as a front frame 2 and a rear frame 5. Panels 3 and 4 are supported by the front frame 2 and the rear frame 5. The intake lip 1 is supported by frame 2. Frame 5 defines the boundary between the intake P1 and the main part of the nacelle, P2. In addition to frames 2 and 5, a reinforcing member 6 is provided on the outer panel 4 to give the intake structure rigidity and provide sufficient strength to withstand the forces and impacts it experiences (such as bird strikes).

[0004] Patent FR 3083777 discloses an air intake 7, which in Figure 2 The design features a single, integrated segment 8 to facilitate its design and maintenance and limit its impact on drag. There is no front frame; rigidity is provided through the integrated appearance. Summary of the Invention

[0005] The present invention aims to go a step further by eliminating the front frame and reinforcement.

[0006] Therefore, the present invention relates to an air inlet including a lip, at least one outer panel extending the lip outward, at least one inner panel extending the lip inward, the wall of the air inlet having a thickness of value e, characterized in that the thickness of the wall of the air inlet varies longitudinally and includes a region Z2 at a longitudinal front end, the thickness of which is greater than the thickness e.

[0007] Therefore, the varying wall thickness of the air inlet allows the effects of removing the front frame and reinforcements to be overcome, and provides the rigidity required to withstand strain.

[0008] The present invention provides at least one of the following optional features, used individually or in combination.

[0009] In addition to the region Z2, which has a thickness e2 less than the thickness e, the air inlet also includes an acoustic treatment region Z4 on the inner surface of the air inlet.

[0010] The air intake includes an intermediate region Z3 located between the front region Z2 and the acoustic treatment region Z4, which has a substantially constant thickness e.

[0011] The air inlet includes at least one joint region Z5 adjacent to the joint between two walls forming the entire wall of the air inlet, the at least one joint region having a thickness of substantially constant value e.

[0012] The thickness e2 of region Z2 varies and is greatest at the transverse line B, which is the longitudinal limit.

[0013] The thickness of region Z2 varies in the longitudinal direction at the same rate on both sides of line B, decreasing from the value e2 at line B to the value e at the longitudinal end of region Z2.

[0014] The maximum thickness e2 of region Z2 at the limit line B is between 30% and 50% greater than the thickness e.

[0015] The thickness e4 of region Z4 is between 30% and 50% smaller than the thickness e.

[0016] The present invention also relates to a nacelle including such an air inlet.

[0017] The present invention also relates to an aircraft equipped with such a nacelle. Attached Figure Description

[0018] Other objects, features, and advantages will become apparent from the following description of the invention, with reference to the accompanying drawings, which are given purely by way of non-limiting example, in which:

[0019] Figure 1 This is a side view of a longitudinal section of an air inlet having a front frame, a rear frame, and a reinforcing member, according to an embodiment of the prior art.

[0020] Figure 2 This is a side view of a longitudinal section of an air inlet with an integral segment, according to another embodiment of the prior art;

[0021] Figure 3 This is a side view of an aircraft with an air intake according to the present invention;

[0022] Figure 4 This is a perspective view of a propulsion assembly with a nacelle according to the present invention, the nacelle having two prominently displayed parts;

[0023] Figure 5 This is a side view of the longitudinal section of the air inlet with varying wall thickness according to the present invention. Detailed Implementation

[0024] like Figure 3 and Figure 4 As indicated, the present invention relates to the nacelle 10 of the propulsion assembly 12 of the aircraft 14.

[0025] As in most propulsion components, and as explained above, such as Figure 4 The nacelle 10, as shown, comprises, from front to back, a first section upstream of the aerodynamic flow (referred to as the air inlet P1 and denoted as 16 in the figure) and a second section constituting the remainder of the nacelle (referred to as the main section P2). The function of the first section is to capture and direct airflow to ensure that it flows toward the fan. The air inlet 16 has an annular circumferential shape.

[0026] The propulsion assembly 12, particularly the nacelle 10, extends about a longitudinal axis referred to as longitudinal axis A. Axis A is the axis of rotation of the air intake 16. The expression "longitudinally" means a direction parallel to the central axis A of the air intake. "Longitudinal plane" is a plane that includes the central axis A of the air intake. Throughout the following description, the concepts of front and rear, front and rear, and upstream and downstream should be understood according to the direction of airflow in the propulsion assembly: air enters through the front of the propulsion assembly (i.e., through air intake P1) and exits through the rear (i.e., the rear end of the second section P2). The expressions "lateral direction" and "laterally" refer to the direction extending in the lateral plane of the air intake, i.e., the direction orthogonal to the central axis A of the air intake.

[0027] The air intake 16 includes an air intake lip 18, which is positioned at the front end and allows for the capture of air required by the engine. An outer panel 20 extends the lip outside the nacelle and forms an outer wall. An inner panel 22 extends the lip inside the nacelle and forms an inner wall. Panels 20 and 22 define internal ducts, thereby enabling the directing of air to a fan (not shown).

[0028] like Figure 5As shown in the longitudinal section, the wall 24 of the air inlet 16, formed by the wall 24A of the lip 18 and the wall 24B of the panel 20, is continuous, i.e., it is integral in the longitudinal direction. In the transverse direction, the air inlet 16 may be made as a single piece or as several circumferential segments fixed to each other. In the illustrated embodiment, there is a joint between the walls 24A and 24C.

[0029] The intake wall 24 according to the invention comprises a longitudinally varying thickness optimized based on strain at a considered horizontal level. Therefore, the wall 24 has several longitudinally successive regions Z1, Z2, Z3, Z4, Z5, the thickness of which varies from one region to the next adjacent region. Regions Z1, Z3, Z4, Z5 have substantially the same thickness over most of their length (longitudinally), and even over their entire length (excluding their longitudinal ends). On the other hand, region Z2 has a longitudinally varying thickness from one end to the other: the thickness increases from value e to value e2, and then decreases from value e2 back to value e. In region Z2, a longitudinal limit line B is located. The increasing thickness results in value e2 being reached at the limit line B. Figure 5 In the embodiment shown, the lengths (in the longitudinal direction) of region Z2 from both sides of line B to regions Z1 and Z3 are the same. Different lengths may be provided according to other embodiments.

[0030] The air intake 16 has: a region located at the longitudinal front end, referred to as the front region Z2; an adjacent region extending from region Z2 on the side of the outer panel 20, referred to as the outer region Z1; a region adjacent to the front region Z2 and extending toward the inner panel 22 to region Z4, referred to as the intermediate inner region Z3; a region Z4 adjacent to the intermediate region Z3 and region Z5, referred to as the specific acoustic treatment region Z4; and a last region Z5 adjacent to region Z4 and wall 24C, referred to as the joining region Z5.

[0031] The thickness e2 of the front region Z2 at line B is greater than that of the adjacent regions Z1 and Z3 because the front region Z2 is most exposed to damage from impacts such as bird strikes, debris of any type, hail, etc., and is therefore most likely to suffer damage. Therefore, the thickness e2 of wall 24 at the front region Z2 is 30% to 50% greater than the thickness e of the wall at the adjacent outer region Z1 and the wall at the adjacent intermediate region Z3. The positioning of the limiting transverse line I1 between regions Z1 and Z2, and the positioning of I2 between regions Z2 and Z3, is determined by the angle Y between the tangent line in the plane longitudinally along the surface of wall 24 at lines I1 and I2 and the axis A: this angle is substantially the same at lines I1 and I2 and is greater than 15 degrees. In the illustrated embodiment, this angle is greater than 20 degrees, a good trade-off that enhances the area most exposed to impacts without compromising weight by increasing the area thickness on an excessively large surface.

[0032] Regions Z1, Z3, and Z5 have the same thickness e, which is the thickness required to allow for the use of fasteners. The joining region Z5, which allows for the joining between walls 24A and 24C, requires fasteners and therefore drilling, necessitating sufficient thickness and thus a thickness of e. Thickness e is also the standard thickness for nacelles, allowing for small-piece repairs that require fasteners.

[0033] Although region Z1 is not located at the front of the nacelle, it is still an exposed area. Therefore, according to other embodiments, the thickness of this region can be greater than the thickness of other regions except for region Z2, which will always have the maximum thickness.

[0034] The specific acoustic treatment zone Z4 is located inside the nacelle; therefore, it has less structural strain and less strain relative to the impact mentioned above. On the other hand, the need for acoustic attenuation is greater. Moreover, specific acoustic treatments can be provided. It should be noted that no fasteners are installed at this level. Therefore, the thickness e4 of zone Z4 is less than the thickness e that will allow the application of sound insulation panels. In the illustrated embodiment, the value of the thickness e4 of zone Z4 is between 30% and 50% smaller than the value of thickness e.

[0035] According to specific embodiments illustrating a series of possible thicknesses, the thickness e of regions Z1, Z3, and Z5 is 2.125 mm. The thickness e2 of the front region Z2 is greater than 3 mm, while the thickness e4 of the acoustic treatment region Z4 is less than 1.6 mm. As seen above, the thickness of the outer region Z1, which serves as the outer surface, can be 2.15 mm, slightly larger than the thicknesses of regions Z3 and Z5. However, to allow for a gradual decrease in thickness from the thicker front region Z2 to the thinner acoustic treatment region Z4, the intermediate region Z3 can have a thickness of approximately 2.2 mm, greater than the wall thickness at regions Z1 or Z5.

[0036] Different wall thicknesses are obtained through machining after wall 24 is formed.

[0037] This invention enables the increase of wall strength while optimizing the performance level of the air intake (weight, acoustics, etc.) and simplifying its manufacture at a lower cost.

Claims

1. An air inlet comprising a lip (18), at least one external panel (20) extending the lip on the outside, at least one internal panel (22) extending the lip on the inside, the wall (24) of the air inlet having a thickness of value e, characterized in that The wall (24) of the air inlet has a thickness that varies longitudinally and comprises a front zone (Z2) at the longitudinal front end, the value e2 of the thickness of which is greater than the thickness e.

2. The air inlet according to claim 1, characterized in that The air inlet includes, in addition to the front area (Z2), an acoustically treated area (Z4) at the inner surface of the air inlet, and a thickness e4 of the acoustically treated area is smaller than the thickness e.

3. The air inlet according to claim 2, characterized in that The air inlet comprises an intermediate zone (Z3) arranged between the front zone (Z2) and the acoustic treatment zone (Z4), the intermediate zone (Z3) having a substantially constant thickness e.

4. The air inlet according to any one of claims 1 to 3, characterized in that The air inlet comprises at least one joining zone (Z5) adjacent to a junction between a wall (24a, 24b) and a wall (24c), the at least one joining zone (Z5) having a thickness of a substantially constant value e, the walls (24a, 24b) and the wall (24c) forming the entire wall (24) of the air inlet.

5. The air inlet according to any one of claims 1 to 4, characterized in that The thickness e2 of the front zone (Z2) varies and is greatest at the longitudinal limit, the transverse line (B).

6. The air inlet according to claim 5, characterized in that The longitudinal variation of the thickness of the front zone (Z2) is the same on both sides of the longitudinal limit transverse line (B) and decreases from a value e2 at the longitudinal limit transverse line (B) to a value e at the longitudinal end of the front zone (Z2).

7. The air inlet according to any one of claims 1 to 6, characterized in that The maximum thickness e2 of the front zone (Z2) at the longitudinal limit transverse line (B) has a value between 30% and 50% greater than the value of the thickness e.

8. The air inlet according to claim 2, characterized in that The value of the thickness e4 of the acoustic treatment zone (Z4) is between 30% and 50% smaller than the value of the thickness e.

9. A nacelle comprising an air inlet according to any one of claims 1 to 8.

10. A propulsion assembly for an aircraft, the propulsion assembly being provided with a nacelle according to claim 9.

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