Aircraft with at least one cavity that exhibits a partial reduction of the passage cross-section on an aerodynamic wall

Description

[0001] This application relates to an aircraft comprising at least one cavity opening at the level of an aerodynamic wall and provided with a partial passage section reduction.

[0002] An example of earlier art is shown in the figures 2 et 3 .

[0003] According to one embodiment, an aircraft 10 comprises a fuselage 12, wings 14 provided on either side of the fuselage 12, and propulsion assemblies 16 connected to the wings by pylons 18. The aircraft 10 comprises at least one air intake device 20, visible on the figure 2 which opens at an aerodynamic wall 22 in contact with an airflow 24 when the aircraft 10 is in flight. This air intake device 20 is configured to capture a portion of the airflow 24 and direct it towards equipment on the aircraft. The aerodynamic wall 22 may be located on the fuselage 12, a wing 14, a propulsion unit 16, or a mast 18.

[0004] According to one configuration, the air intake device 20 comprises an intake duct 26, which extends between a first end 26.1 connected to the aerodynamic wall 22 and a second end 26.2, and a valve 28 connected to the second end 26.2 of the intake duct 26 and configured to occupy a passing state in which the valve 28 allows a flow of air channeled through the intake duct 26 to pass through it and a closed state in which the valve 28 blocks the flow of air in the intake duct 26.

[0005] In one configuration, the first end 26.1, which opens at the level of the aerodynamic wall 22, is flared and forms a flush-type air inlet. In this configuration, the first end 26.1 of the intake duct 26 is positioned on a reference surface substantially parallel to the airflow 24, said reference surface being, outside the intake duct 26, coincident with the outer face of the aerodynamic wall 22 in contact with the airflow 24.

[0006] The air intake device 20 is optimized to reduce aircraft drag when the valve 28 is in the open state.

[0007] When valve 28 is in the closed state, the inlet duct 26 and valve 28 in the closed state form a cavity 30, schematically represented on the figure 3 , which opens at the level of the aerodynamic wall 22. The airflow 24 which flows over the cavity 30 generates an aerodynamic noise, in particular a whistling, due to the coupling between a return airflow 24.1 formed in the cavity 30 and a disturbed flow 24.2 appearing after the upstream edge 30.1 of the cavity 30.

[0008] Document EP1828571 describes a ventilation air inlet that has a deformable area to adjust the air inlet's cross-section. This area extends over a small portion of the air inlet's circumference.

[0009] Document EP1251069 describes a double air inlet which includes two inlet channels, one of which is fitted with a flap to close it off.

[0010] Document EP0926064B1 describes a flow control device for eliminating flow-induced cavity resonance in a closed or nearly closed flow passage. This passage has an inlet opening defined between an upstream and a downstream inlet edge and a bottom closed by a butterfly valve. The passage receives the flow of external fluid through the opening. The flow control device includes a fixed inlet fin with a leading edge, a trailing edge, and several support elements connecting it to the inlet. The fin is positioned so that its leading edge intercepts the shear layer of the external fluid flow and its trailing edge extends into the passage at the inlet.Flow-induced cavity resonance is reduced or eliminated in the closed or nearly closed end passage by intercepting the free shear layer passing over the inlet opening by the flow control device.

[0011] The present invention aims to remedy all or part of the drawbacks of the prior art. To this end, the invention relates to an aircraft according to claim 1.

[0012] According to the invention, the cavity includes at least one reduction in the cross-sectional area, located away from the bottom, which extends only over a portion of the circumference of the tubular side wall. The fact that the reduction in cross-sectional area is located away from the bottom and is partial (not continuous around the entire circumference of the tubular side wall) makes it possible to achieve a reduction in aerodynamic noise.

[0013] Other features and advantages will become apparent from the following description of the invention, given by way of example only, with reference to the accompanying drawings, among which: There figure 1 is a side view of an aircraft, The figure 2 is a longitudinal section of an air intake device illustrating a prior art embodiment, The figure 3 is a schematic representation of the air intake system, visible on the figure 2 forming a cavity as well as airflows circulating above and within said cavity, The figure 4 is a side view of an air intake device forming a cavity illustrating one embodiment of the invention, The figure 5 is a side view of an intake duct illustrating an embodiment of the invention, a portion of the intake duct not being shown to visualize the interior of said intake duct, The figure 6 is a cross-section of a cavity provided with a reduced passage cross-section illustrating one embodiment of the invention, The figure 7 is a section along line VII-VII of the figure 6 of the cavity provided with a reduction in passage cross-section illustrating one embodiment of the invention.

[0014] According to one embodiment on the figure 4 , an aircraft includes at least one aerodynamic wall 40 and at least one air intake device 42.

[0015] The aerodynamic wall 40 has an outer face F40 against which an airflow 44 flows in a specific direction when the aircraft is in flight. The aerodynamic wall can be located on the fuselage, a wing, a propulsion unit, or a mast of the aircraft.

[0016] The air intake device 42 includes an intake duct 46, which extends between a first end 46.1 connected to the aerodynamic wall 40 and a second end 46.2, and a valve 48 connected to the second end 46.2 of the intake duct 46 and configured to occupy a passing state in which the valve 48 allows a flow of air channeled through the intake duct 46 to pass through it and a closed state in which the valve 48 blocks the flow of air in the intake duct 46.

[0017] In one configuration, the first end 46.1 opens at the aerodynamic wall 40 and has a shape that flares out towards the outer face F40 of the aerodynamic wall 40. Thus, the first end 46.1 of the intake duct 46 forms a flush-type air inlet. In this configuration, the first end 46.1 of the intake duct 46 is positioned on a reference surface S substantially parallel to the airflow 44, said reference surface S being, outside the intake duct 46, coincident with the outer face F40 of the aerodynamic wall 40 in contact with the airflow 44. The reference surface S and the outer face F40 can be either flat or curved.

[0018] When the valve 48 is in the closed state, the inlet duct 46 and the valve 48 in the closed state form a cavity 50 which opens at the level of the aerodynamic wall 40.

[0019] This cavity 50 is delimited by a tubular side wall 52 (corresponding to the inlet duct 46), which extends between the first and second ends 52.1, 52.2, and by a bottom 54 (corresponding to the valve 48 and more particularly to the valve flap) located away from the aerodynamic wall 40 and situated at the level of the second end 52.2 of the tubular side wall 52, the first end 52.1 of the tubular side wall 52 (corresponding to the first end 46.1 of the inlet duct 46) being situated at the level of the outer face F40 of the aerodynamic wall 40. The tubular side wall 52 is substantially parallel to a reference direction DD which may be perpendicular or inclined with respect to the reference surface S. By way of example, the reference direction DD forms an angle of approximately 60° with the reference surface S.

[0020] The tubular side wall 52 is cylindrical and has an axis of revolution A52 parallel to the reference direction.

[0021] According to one arrangement, the bottom 54 is substantially perpendicular to the reference direction DD.

[0022] The cavity 50 has a reference passage cross-section Sr corresponding to the cross-section of the tubular side wall 52. Since the latter is cylindrical, the reference passage cross-section Sr is characterized by a diameter Dr, as illustrated in the figure 6 .

[0023] The cavity 50 has a depth P corresponding to the average distance between the reference surface S and the bottom 54. The tubular side wall 52 being cylindrical, the depth P corresponds to a distance separating a first point of intersection between the axis of revolution A52 and the reference surface S and a second point of intersection between the axis of revolution A52 and the bottom 54.

[0024] According to one feature of the invention, the cavity 50 includes at least one partial reduction in cross-section 56 located away from the bottom 54. By partial, it is understood that the reduction in cross-section 56 extends only over a portion of the circumference of the tubular side wall 52 and not over the entire circumference.

[0025] According to one configuration, the passage section reduction 56 is positioned in a transverse plane perpendicular to the reference direction DD. This transverse plane is located at a distance from the bottom 54 of the order of 30% of the depth P with a tolerance interval of + / - 20% and preferably of + / - 5%.

[0026] Depending on the configuration, the passage section reduction 56 has a passage area of ​​approximately 80% of the reference passage area Sr, with a tolerance range of approximately + / - 10%, preferably + / - 5%. Since the tubular side wall 52 is cylindrical and has a reference diameter Dr, the passage section reduction 56 has a diameter D56 of approximately 80% of the reference diameter Dr, with a tolerance range of approximately + / - 10%, preferably + / - 5%.

[0027] According to one arrangement, the reduction of the passage section 56 extends over half the circumference of the tubular side wall 52 with a tolerance interval of + / - 20% and preferably of + / - 5%.

[0028] According to one arrangement, when the tubular side wall 52 is inclined, the passage section reduction 56 is positioned in an upstream half-space delimited by a median plane, passing through the axis of revolution A52, perpendicular to the direction of flow of the airflow 44. The term upstream refers to the direction of flow of the airflow 44, which flows from upstream to downstream.

[0029] According to one embodiment, the passage section reduction 56 comprises a rib 58, projecting from the tubular side wall 52, having a first edge 58.1 extending from the tubular side wall 52, oriented towards the first end 52.1 of the tubular side wall 52, and a second edge 58.1 extending from the tubular side wall 52, oriented towards the bottom 54.

[0030] According to one configuration, the first edge 58.1 forms an angle A1 with the tubular side wall 52 between 20 and 60°, preferably between 30 and 40°.

[0031] According to one arrangement, the second edge 58.2 is substantially perpendicular to the tubular side wall 52.

[0032] In one embodiment, the rib 58 has an intermediate zone 58.3 interposed between and connecting the first and second edges 58.1, 58.2. In one configuration, this intermediate zone 58.3 may be curved.

[0033] According to an embodiment visible on the figure 7 , the rib 58 is a hollow bead attached to the tubular side wall 52. For information purposes, the rib 58 is made of plastic and fixed to the tubular side wall 52 by gluing or any other means.

[0034] Rib 58 could be solid. The fact that the tube is hollow helps to reduce the mass.

[0035] The fact that the reduction of the passage section 56 is distant from the bottom 54 and partial (not continuous over the entire circumference of the tubular side wall 52) makes it possible to obtain a reduction of noise of aerodynamic origin.

Claims

1. Aircraft comprising at least one aerodynamic wall (40) against which an airflow (44) flows in a direction of flow when the aircraft is in flight and an air intake device (42) which comprises: - an intake duct (46), which extends between a first end (46.1) connected to the aerodynamic wall (40) and a second end (46.2), - a valve (48) connected to the second end (46.2) of the intake duct (46) and configured to occupy a permissive state in which the valve (48) allows an airflow channeled by the intake duct (46) to pass through it and a closed state in which the valve (48) blocks the airflow in the intake duct (46), the intake duct (46) and the valve (48) in the closed state delimiting a cavity (50) that opens at the aerodynamic wall (40), said cavity (50) being delimited by a tubular lateral wall (52) that extends between first and second ends (52.1, 52.2) and by a bottom (54) spaced apart from the aerodynamic wall (40) and situated at the second end (52.2) of the tubular lateral wall (52), the first end (52.1) of the tubular lateral wall (52) being situated at the aerodynamic wall (40) on a reference surface (S) substantially parallel to the airflow (44), the cavity (50) having a reference passage section (Sr) and a depth (P), the tubular lateral wall (52) being cylindrical, having an axis of revolution (A52) and parallel to a reference direction (DD) and having a circumference, the depth (P) corresponding to the distance between a first point of intersection of the axis of revolution (A52) with the reference surface (S) and a second point of intersection of the axis of revolution (A52) with the bottom (54); the cavity (50) comprising at least one reduction in passage section (56), spaced apart from the bottom (54), which extends only over a part of the circumference of the tubular lateral wall (52), the tubular lateral wall (54) having a reference diameter (Dr) , the reduction in passage section (56) having a diameter (D56) of the order of 80% of the reference diameter (Dr) with a tolerance interval of the order of + / - 10%, preferably of + / - 5%.

2. Aircraft as claimed in the preceding claim, wherein the reduction in passage section (56) extends over half the circumference of the tubular lateral wall (52) with a tolerance interval of + / - 20%, preferably of + / - 5%.

3. Aircraft as claimed in the preceding claim, wherein the reduction in passage section (56) is positioned in an upstream half-space delimited by a median plane passing through the axis of revolution (A52), perpendicular to the direction of flow of the airflow (44), the term upstream referring to the direction of flow of the airflow (44), which flows from upstream to downstream.

4. Aircraft as claimed in one of the preceding claims, wherein the reduction in passage section (56) is positioned in a transverse plane perpendicular to the reference direction (DD).

5. Aircraft as claimed in the preceding claim, wherein the transverse plane is situated at a distance from the bottom (54) of the order of 30% of the depth (P) of the cavity (50) with a tolerance interval of + / - 20%, preferably of + / - 5%.

6. Aircraft as claimed in one of the preceding claims, wherein the reduction in passage section (56) has a passage section of the order of 80% of the reference passage section (Sr) with a tolerance interval of the order of + / - 10%, preferably of + / - 5%.

7. Aircraft as claimed in one of the preceding claims, wherein the reduction in passage section (56) comprises a rib (58), projecting with respect to the tubular lateral wall (52), having a first edge face (58.1) that extends from the tubular lateral wall (52), oriented toward the first end (52.1) of the tubular lateral wall (52), and a second edge face (58.1) that extends from the tubular lateral wall (52), oriented toward the bottom (54).

8. Aircraft as claimed in the preceding claim, wherein the first edge face (58.1) forms an angle with the tubular lateral wall (52) of between 20 and 60°, preferably of between 30 and 40°.

9. Aircraft as claimed in either of claims 7 and 8, wherein the second edge face (58.2) is substantially perpendicular to the tubular lateral wall (52).

10. Aircraft as claimed in one of claims 7 to 9, wherein the rib (58) is a hollow roll attached against the tubular lateral wall (52).