Variable panel low resistance acoustic device

Abstract

This invention discloses a low-resistance sound-absorbing device with a variable panel, comprising: a leading-edge connector, a flexible panel assembly, a sound-absorbing assembly, a locking device, and a trailing-edge connector arranged sequentially along the axial direction and with their upper surfaces flush; the positive x-axis is defined as the direction parallel to the upper surface of the leading-edge connector and pointing from the leading-edge connector to the trailing-edge connector, and the y-axis is defined as the direction perpendicular to the upper surface of the leading-edge connector; the leading-edge connector is used to connect to the upstream air intake and guide the upstream airflow; the trailing-edge connector is used to connect to the downstream fan casing and guide the airflow downstream; the flexible panel assembly includes a flexible panel that can be unfolded or retracted along the x-axis direction. When unfolded, the other end of the flexible panel is fixed by the locking device, and the flexible panel covers the upper surface of the sound-absorbing assembly; when retracted, the upper surface of the sound-absorbing assembly is exposed for sound absorption. This invention can adjust the panel according to the aircraft's flight conditions, achieving a balance between low noise and low fuel consumption for the aircraft.

Description

Technical Field

[0001] This invention relates to the field of aircraft engine nacelles, and more particularly to a low-resistivity sound-absorbing device with a variable panel. Background Technology

[0002] Airplanes are an essential part of modern transportation, enabling people to reach destinations around the world quickly and safely. Whether for business or leisure travel, airplanes are one of the fastest and most convenient modes of transport. Airplanes have not only changed the way people travel but have also had a profound impact on the economy, culture, and technology. Civilian aircraft, in particular, offer advantages such as high speed, comfort, safety, and wide coverage, but they also have some drawbacks, one of which is noise.

[0003] A complete flight of a civil aircraft includes takeoff, cruise, and landing phases. During takeoff, the engines operate at full power to provide the thrust required for takeoff, generating noise levels that can typically reach 150 decibels. This can affect passengers in the cabin, as well as the surrounding environment and residents. During landing, because the aircraft is closer to the ground, the noise generated by the engines still has a significant impact on the surrounding environment. A common noise reduction method in existing technology is to install sound-absorbing liners in the engine nacelles to reduce noise. During cruise, the engine thrust only needs to balance the drag on the aircraft, so the required engine power is greatly reduced, and the noise generated by the engine is also greatly reduced. At this point, the noise impact on the cabin is negligible; however, the perforated surface of the sound-absorbing liner creates additional drag, leading to increased fuel consumption. In summary, existing technologies lack engine auxiliary devices that can achieve both low noise and low fuel consumption requirements for aircraft. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a low-resistance sound-absorbing device with a variable panel. The specific technical solution is as follows:

[0005] A low-resistance sound-absorbing device with a variable panel includes: a leading edge connector, a flexible panel assembly, a sound-absorbing assembly, a locking device, and a trailing edge connector arranged sequentially along the axial direction and with their upper surfaces flush; the positive x-axis is defined as the direction parallel to the upper surface of the leading edge connector and pointing from the leading edge connector to the trailing edge connector, and the y-axis is defined as the direction perpendicular to the upper surface of the leading edge connector; the leading edge connector is used to connect to the upstream air intake and guide the upstream airflow; the trailing edge connector is used to connect to the downstream fan casing and guide the airflow downstream;

[0006] The flexible panel assembly includes a flexible panel that can be unfolded or retracted along the x-axis. When unfolded, the other end of the flexible panel is fixed by a locking device, and the flexible panel covers the upper surface of the sound-absorbing assembly. When retracted, the upper surface of the sound-absorbing assembly is exposed for sound absorption.

[0007] Furthermore, the flexible panel assembly also includes: a base, a housing, and a motor; the motor is mounted on the top of the base, and a hollow housing is coaxially arranged around the outer periphery of the motor; one end of the flexible panel is fixed inside the housing, and the flexible panel is wrapped around and housed in the housing in the circumferential direction; the outlet tangent of the housing is flush with the upper surface of the leading edge connector; if the motor rotates in the positive direction, it drives the flexible panel to extend along the positive x-axis and cover the upper surface of the sound-absorbing assembly; if the motor rotates in the reverse direction, it drives the flexible panel to retract into the housing along the negative x-axis.

[0008] Furthermore, the housing includes: a protective shell, ball bearings, and a limiter; the protective shell is wrapped around the outermost part of the housing to protect and support the remaining components; the protective shell is provided with ball bearings arranged radially in space, and the channels formed by the ball bearings are used to limit the movement trajectory of the flexible panel and reduce friction; a limiter is provided at the outlet of the protective shell to prevent the flexible panel from retracting excessively; the end of the flexible panel has a wedge-shaped protrusion, which cooperates with the limiter to play a limiting role.

[0009] Furthermore, the motor includes: a three-lobe motor shaft, a circular rotating component, and a connector; the three-lobe motor shaft is installed at the axial position of the housing, the circular rotating component is coaxially arranged on the outside of the three-lobe motor shaft, and the connector is fixedly connected to the circular rotating component; the connector is connected to the end point of the flexible panel.

[0010] Furthermore, the sound-absorbing component includes: a sound absorber, a supporting plane, a second motor, and a lifting device; the supporting plane is fixedly connected to the lifting device, and the supporting plane is parallel to the upper surface of the front edge connector; the second motor is connected to the lifting device and controls the lifting device to rise or fall along the y-axis direction; the sound absorber is fixedly connected to the upper surface of the supporting plane, and the length of the flexible panel in the x-axis direction is greater than the length of the sound absorber panel in the x-axis direction.

[0011] Furthermore, the sound absorber has a sandwich structure, including: a perforated plate, a honeycomb core, and a rigid back plate; the perforated plate and the rigid back plate are both arranged parallel to the supporting plane, the honeycomb core is arranged between the perforated plate and the rigid back plate, and the rigid back plate is fixedly connected to the upper surface of the supporting plane.

[0012] Furthermore, the materials of the perforated plate and the rigid back plate are both aerospace aluminum alloys, and the material of the honeycomb core is a resin-based composite material.

[0013] Furthermore, the flexible panel is made of polyester material and has a self-lubricating Teflon wear-resistant layer on its surface.

[0014] The beneficial effects of this invention are:

[0015] This invention can adjust the panel according to the aircraft's flight conditions. It can use sound absorbers to meet the noise reduction requirements of the aircraft during takeoff and landing, and use low-resistance flexible panels to avoid the additional flight drag caused by sound absorbers during the cruise phase, thus achieving a balance between low noise and low fuel consumption for the aircraft. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the low-resistivity sound-absorbing device with a variable panel in sound-absorbing mode according to an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of the structure of the low-resistance sound-absorbing device with a variable panel in the drag reduction mode according to an embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram of the internal structure of the housing of the flexible panel assembly according to an embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of the sound absorber structure according to an embodiment of the present invention.

[0020] Figure 5 This is a schematic diagram showing the arrangement of the variable panel low-resistance sound-absorbing device on the nacelle of an aircraft engine, according to an embodiment of the present invention.

[0021] Figure 6 This is a comparative experimental result diagram of the resistance coefficients of the sound absorber and the flexible panel used in the embodiments of the present invention.

[0022] In the figure, the leading edge connector is 1, the flexible panel assembly is 2, the sound-absorbing assembly is 3, the locking device is 4, and the trailing edge connector is 5.

[0023] Base 2-1, housing 2-2, motor 1 2-3, flexible panel 2-4; protective shell 2-2-1, ball bearing 2-2-2, limiter 2-2-3; three-lobe motor shaft 2-3-1, circular rotating part 2-3-2, connector 2-3-3;

[0024] 3-1 sound absorber, 3-2 supporting plane, 3-3 motor, 3-4 lifting device; 3-1-1 perforated plate, 3-1-2 honeycomb core, 3-1-3 rigid back plate. Detailed Implementation

[0025] The present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. The objectives and effects of the present invention will become clearer as a result. The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0026] like Figure 1 , Figure 2 As shown, a low-resistance sound-absorbing device with a variable panel includes, in sequence along the axial direction: a leading edge connector 1, a flexible panel assembly 2, a sound-absorbing assembly 3, a locking device 4, and a trailing edge connector 5. The upper surfaces (i.e., the airflow plane) of each component are kept flush. The positive x-axis is defined as the direction parallel to the upper surface and pointing from the leading edge connector 1 to the trailing edge connector 5, and the positive y-axis is defined as the direction perpendicular to the upper surface of the leading edge connector 1 and pointing from the upper surface to the lower surface. The leading edge connector 1 connects to the upstream air intake, guiding the upstream airflow. The trailing edge connector 5 connects to the locking device 4, connecting to the downstream fan casing and guiding the airflow downstream.

[0027] The flexible panel assembly 2 is connected to the leading edge connector 1. The flexible panel assembly 2 includes: a base 2-1, a housing 2-2, a motor 2-3, and a flexible panel 2-4. The base 2-1 is fixed to the bottom of the housing of the low-resistance sound-absorbing device of the variable panel. The motor 2-3 is mounted on the top of the base 2-1. The hollow housing 2-2 is coaxially arranged around the outer periphery of the motor 2-3. One end of the flexible panel 2-4 is fixed inside the housing 2-2 and connected to the motor 2-3. The flexible panel 2-4 is circumferentially wound and housed in the housing 2-2. The outlet tangent of the housing 2-2 is flush with the upper surface of the leading edge connector 1. The flexible panel 2-4 is made of polyester material with a self-lubricating Teflon wear-resistant layer on its surface. If motor 2-3 rotates in the positive direction, it drives the flexible panel 2-4 to extend along the positive x-axis to cover the upper surface of the sound-absorbing component 3. The locking device 4 is used to fix the flexible panel 2-4 in the unfolded state. If motor 2-3 rotates in the reverse direction, it drives the flexible panel 2-4 to retract into the housing 2-2 along the negative x-axis.

[0028] like Figure 3As shown, the housing 2-2 includes: a protective shell 2-2-1, ball bearings 2-2-2, and a limiter 2-2-3. The protective shell 2-2-1 covers the outermost part of the housing 2-2 and is used to protect and support the remaining components. The ball bearings 2-2-2 are arranged radially on the protective shell 2-2-1, forming channels that limit the movement trajectory of the flexible panel 2-4 and reduce friction, facilitating the unfolding and retraction of the flexible panel 2-4. A limiter 2-2-3 is provided at the outlet of the protective shell 2-2-1 to prevent the flexible panel 2-4 from over-retracting; correspondingly, the end of the flexible panel 2-4 has a wedge-shaped protrusion, which cooperates with the limiter 2-2-3 to provide a limiting function. In this embodiment, the protective shell 2-2-1 is provided with 31 ball bearings 2-2-2.

[0029] The motor 2-3 includes: a three-lobe motor shaft 2-3-1, a circular rotating component 2-3-2, and a connector 2-3-3. The three-lobe motor shaft 2-3-1 is mounted at the axial center of the housing 2-2. The circular rotating component 2-3-2 is coaxially arranged on the outside of the three-lobe motor shaft 2-3-1. The connector 2-3-3 is fixedly connected to the circular rotating component 2-3-2. The rotation of the three-lobe motor shaft 2-3-1 generates torque, driving the circular rotating component 2-3-2 to rotate. The circular rotating component 2-3-2 is connected to the end of the flexible panel 2-4 through the connector 2-3-3, ultimately driving the flexible panel 2-4 to unfold or retract.

[0030] The sound-absorbing component 3 is arranged between the flexible panel assembly 2 and the locking device 4. The sound-absorbing component 3 includes: a sound absorber 3-1, a supporting plane 3-2, a second motor 3-3, and a lifting device 3-4. One end of the lifting device 3-4 is fixedly connected to the bottom of the housing of the low-resistance sound-absorbing device of the variable panel, and the other end is fixedly connected to the lower surface of the supporting plane 3-2. The second motor 3-3 is connected to the lifting device 3-4 and controls the lifting device 3-4 to rise or fall along the y-axis. The supporting plane 3-2 is parallel to the upper surface of the front edge connector 1. The sound absorber 3-1 is fixedly connected to the upper surface of the supporting plane 3-2. The length of the flexible panel 2-4 in the x-axis direction is greater than the length of the sound absorber 3-1 panel in the x-axis direction.

[0031] like Figure 4As shown, in one embodiment, the sound absorber 3-1 has a sandwich structure, including: a perforated plate 3-1-1, a honeycomb core 3-1-2, and a rigid back plate 3-1-3. The perforated plate 3-1-1 and the rigid back plate 3-1-3 are arranged in parallel and parallel to the supporting plane 3-2. The honeycomb core 3-1-2 is arranged between the perforated plate 3-1-1 and the rigid back plate 3-1-3. The perforated plate 3-1-1 is close to the upper surface of the low-resistance sound-absorbing device of the variable panel, and the rigid back plate 3-1-3 is fixedly connected to the upper surface of the supporting plane 3-2. The perforated plate 3-1-1 has multiple through holes of the same diameter. The honeycomb core 3-1-2 is a low-density honeycomb material, commonly used as the core material in sandwich structures. The perforated plate 3-1-1 and the rigid back plate 3-1-3 are both made of aerospace aluminum alloy, while the honeycomb core 3-1-2 is made of resin-based composite material.

[0032] The structure of the sound absorber 3-1 is not limited to the above embodiments; any element with sound-absorbing effect is applicable to this invention. The selection and structural parameter settings of the sound absorber 3-1 are related to the airflow direction and sound wave direction, which depend on the position of the low-resistance sound-absorbing device with variable panels on the aircraft engine nacelle. Figure 5 As shown, the sound source area is located in the middle of the engine flow channel, and the low-resistivity sound-absorbing device arrangement area of ​​the variable panel is divided into upstream ( Figure 5 (middle left) and downstream ( Figure 5 There are two types (right and middle). For the upstream region, the airflow direction and the sound wave direction are opposite; for the downstream region, the airflow direction and the sound wave direction are the same. The relative relationship between the airflow direction and the sound wave direction will affect the parameter design of the sound absorber 3-1. According to at least one embodiment of the present invention, the affected parameters include: the pore diameter of the perforated plate 3-1-1, the perforation rate of the perforated plate 3-1-1, the thickness of the perforated plate 3-1-1, and the height of the honeycomb core 3-1-2.

[0033] In practical applications, the low-resistivity sound-absorbing device with variable panels has the following two operating modes:

[0034] (1) Sound absorption mode: Motor 1 2-3 rotates in the opposite direction, driving the flexible panel 2-4 to retract into the housing 2-2 along the negative x-axis; then Motor 2 3-3 drives the lifting device 3-4 along... Figure 1 The absorber moves (i.e. rises) in the negative y-axis direction, eventually making the upper surface of the absorber 3-1 flush with the upper surface of the locking device 4.

[0035] (2) Drag Reduction Mode: Motor 2 3-3 drives lifting device 3-4 along Figure 1The flexible panel 2-4 moves in the positive y-axis direction (i.e., descends) to allow space for its extension. Then, the motor 2-3 rotates in the positive direction, driving the flexible panel 2-4 to extend along the positive x-axis, unfolding flat until it is locked at the locking device 4. At this point, the effect of the flexible panel 2-4 unfolding and covering the upper surface of the sound absorber 3-1 is equivalent to a smooth, unperforated panel.

[0036] To demonstrate that the present invention effectively reduces aircraft drag in drag reduction mode, the drag coefficients of the device with only the sound absorber 3-1 and the device with the flexible panels 2-4 were compared. The experimental results are as follows: Figure 5 As shown. Figure 5 In the figure, the horizontal axis represents the aircraft Mach number, with 0.1 to 0.6 representing the continuous operating conditions from takeoff to cruise. The vertical axis represents the measured drag coefficient. It can be seen that under all Mach number conditions, the drag coefficient with flexible panel 2-4 is always less than the drag coefficient with only sound absorber 3-1. The drag coefficient is reduced by 17% to 52% after using flexible panel 2-4, which shows that the drag reduction effect is obvious.

[0037] This invention proposes a low-resistance sound-absorbing device with a variable panel, arranged on the inner wall of an aircraft engine nacelle. The panel of the sound-absorbing device can be changed according to the aircraft's flight conditions. During takeoff or landing, the flexible panel 2-4 retracts into the housing 2-2, exposing the sound absorber 3-1 to absorb the radiated noise generated by the engine, ensuring the aircraft meets civil aircraft airworthiness standards during takeoff. When the aircraft climbs to high altitude and enters cruise mode, the motor 2-3 drives the flexible panel 2-4 to extend horizontally, covering the perforated plate 3-1-1 of the sound absorber 3-1, eliminating the additional drag introduced by the perforated plate 3-1-1, thereby reducing the aircraft's overall drag and lowering fuel consumption. This invention achieves the goals of absorbing aircraft engine noise during takeoff and landing, and reducing flight drag during high-altitude cruise, thus achieving low noise and low fuel consumption for the aircraft.

[0038] It will be understood by those skilled in the art that the above descriptions are merely preferred examples of the invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, those skilled in the art can still modify the technical solutions described in the foregoing examples or make equivalent substitutions for some of the technical features. All modifications and equivalent substitutions made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A variable panel low resistance sound absorbing device, characterized by, The system includes the following components arranged axially and with their upper surfaces flush: a leading edge connector, a flexible panel assembly, a sound-absorbing assembly, a locking device, and a trailing edge connector; the positive x-axis is defined as the direction parallel to the upper surface of the leading edge connector and pointing from the leading edge connector to the trailing edge connector, and the y-axis is defined as the direction perpendicular to the upper surface of the leading edge connector; the leading edge connector is used to connect to the upstream air intake and guide the upstream airflow; the trailing edge connector is used to connect to the downstream fan casing and guide the airflow downstream; The flexible panel assembly includes a flexible panel that can be unfolded or retracted along the x-axis. When unfolded, the other end of the flexible panel is fixed by a locking device, and the flexible panel covers the upper surface of the sound-absorbing assembly. When retracted, the upper surface of the sound-absorbing assembly is exposed for sound absorption. The flexible panel assembly further includes: a base, a housing, and a motor; the motor is mounted on the top of the base, and a hollow housing is coaxially arranged around the outer periphery of the motor; one end of the flexible panel is fixed inside the housing, and the flexible panel is wrapped around and housed in the housing in the circumferential direction; the outlet tangent of the housing is flush with the upper surface of the leading edge connector; if the motor rotates in the positive direction, it drives the flexible panel to extend along the positive x-axis and cover the upper surface of the sound-absorbing assembly; if the motor rotates in the reverse direction, it drives the flexible panel to retract into the housing along the negative x-axis. The housing includes: a protective shell, ball bearings, and a limiter; the protective shell is provided with ball bearings arranged radially in space, and the channels formed by the ball bearings are used to limit the movement trajectory of the flexible panel and reduce friction; a limiter is provided at the outlet of the protective shell; the end of the flexible panel has a wedge-shaped protrusion, which cooperates with the limiter to play a limiting role. The motor includes: a three-lobe motor shaft, a circular rotating component, and a connector; the three-lobe motor shaft is installed at the axial center of the housing, the circular rotating component is coaxially arranged on the outside of the three-lobe motor shaft, and the connector is fixedly connected to the circular rotating component; the connector is connected to the end of the flexible panel. The sound-absorbing assembly includes: a sound absorber, a supporting plane, a second motor, and a lifting device; the supporting plane is fixedly connected to the lifting device, and the supporting plane is parallel to the upper surface of the front connector; the second motor is connected to the lifting device and controls the lifting device to rise or fall along the y-axis; the sound absorber is fixedly connected to the upper surface of the supporting plane, and the length of the flexible panel in the x-axis direction is greater than the length of the sound absorber in the x-axis direction. The sound absorber has a sandwich structure, including: a perforated plate, a honeycomb core, and a rigid back plate; the perforated plate and the rigid back plate are both arranged parallel to the supporting plane, the honeycomb core is arranged between the perforated plate and the rigid back plate, and the rigid back plate is fixedly connected to the upper surface of the supporting plane.

2. The low-resistivity sound-absorbing device with a variable panel according to claim 1, characterized in that, The perforated plate and rigid back plate are both made of aerospace aluminum alloy, and the honeycomb core is made of resin-based composite material.

3. The low-resistivity sound-absorbing device with a variable panel according to claim 1, characterized in that, The flexible panel is made of polyester material and has a self-lubricating Teflon wear-resistant layer on its surface.

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