Synthetic jet controlled multi-element high-lift device

Abstract

The application discloses a synthetic jet control multi-section wing high-lift device, and relates to the technical field of flow control, which comprises a multi-section wing and a synthetic jet mechanism. A mounting groove is arranged in the middle of the multi-section wing, and the mounting groove is arranged close to the trailing edge of the multi-section wing. The synthetic jet mechanism is installed in the mounting groove. The jet direction of the synthetic jet mechanism is tangential to the side wall of the multi-section wing. The synthetic jet mechanism is driven by an alternating power source. The synthetic jet control multi-section wing high-lift device can improve the aerodynamic performance of the wing in the full angle of attack range.

Description

A synthetic jet-controlled multi-segment wing lift enhancement device Technical Field

[0001] This invention relates to the field of flow control technology, specifically to a synthetic jet control multi-segment wing lift enhancement device. Background Technology

[0002] In the design and development of aircraft, flow control technology, without relying on complex aerodynamic shapes, achieves desired flow states by applying external disturbances, thus enabling purposes such as increased lift and reduced drag, noise and vibration reduction, and thrust vectoring. Based on the presence or absence of energy input, flow control can be divided into passive and active control. Active control technology, as one of the cutting-edge technologies in the aviation field, injects energy into the flow field and is applicable to various flow phenomena. Synthetic jet exciters are one of the most widely used active flow control technologies. They induce vortex structures through periodic blowing and sucking to control the external flow field, demonstrating good effectiveness in controlling wing-separated flow.

[0003] In the current civil aircraft field, multi-segment wings are the main wing configuration, which combine traditional lift-enhancing devices such as leading-edge slats and trailing-edge flaps. However, they lack active flow control technology to provide a more efficient lift enhancement method. Typically, components such as trailing-edge flaps or ailerons operate at a large angle of attack, resulting in severe flow separation and stall at the wing's trailing edge. This leads to insufficient lift and increased drag, significantly impacting the lift enhancement effect of multi-segment wings. Summary of the Invention

[0004] The purpose of this invention is to provide a synthetic jet-controlled multi-segment wing lift enhancement device to solve the problems existing in the prior art and improve the aerodynamic performance of the wing across the entire angle of attack range.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] This invention provides a synthetic jet control multi-segment wing lift enhancement device, including a multi-segment wing and a synthetic jet mechanism. The multi-segment wing has a mounting groove in the middle, and the mounting groove is located near the trailing edge of the multi-segment wing. The synthetic jet mechanism is installed in the mounting groove, and the jet direction of the synthetic jet mechanism is tangential along the side wall of the multi-segment wing. The synthetic jet mechanism is driven by an alternating power supply.

[0007] Preferably, the multi-segment wing includes a main wing, a leading-edge slat, a trailing-edge flap, and a lower cover plate. The mounting groove is formed on the lower end face of the middle part of the main wing. The lower cover plate is bolted to the mounting groove and encapsulates the synthetic jet mechanism in the mounting groove. The leading-edge slat and the trailing-edge flap are respectively mounted on the leading edge and trailing edge of the main wing.

[0008] Preferably, the connection between the main wing and the trailing edge flap is arc-shaped, and the jet outlet of the synthetic jet mechanism is located at the connection between the main wing and the trailing edge flap.

[0009] Preferably, the synthetic jet mechanism includes a synthetic jet driver and a plurality of synthetic jet exciters. The synthetic jet driver is used to drive each of the synthetic jet exciters to work. The synthetic jet driver includes a signal generator and a voltage amplifier. The synthetic jet exciter is provided with a piezoelectric ceramic plate.

[0010] Preferably, the synthetic jet exciter includes a circular cavity, an outlet pipe, the piezoelectric ceramic sheet, and a middle plate. The circular cavity is formed on the inner bottom surface of the mounting groove. One end of the outlet pipe communicates with the circular cavity, and the other end extends to the trailing edge of the multi-segment wing. An annular step is provided on the side wall of the circular cavity. The piezoelectric ceramic sheet is located on the annular step. An annular protrusion is provided on the middle plate at the position corresponding to the annular step. A circular through hole communicating with the circular cavity is formed in the annular protrusion. The annular protrusion is embedded in the annular step and presses down on the piezoelectric ceramic sheet. The main wing, the middle plate, and the lower cover plate are all connected together.

[0011] Preferably, the upper end of the lower cover plate is provided with an embedding groove, the middle layer plate is located in the embedding groove, and a wire groove is provided on one side of the embedding groove. One end of the wire groove is connected to the outside, and the other end of the wire groove is connected to the embedding groove.

[0012] Preferably, multiple threaded holes are provided in the mounting groove, the middle layer plate, and the lower cover plate, and bolts are used to connect the mounting groove, the middle layer plate, and the lower cover plate through the threaded holes located in different layers.

[0013] Preferably, the outlet pipe is a rectangular pipe.

[0014] Preferably, the synthetic jet exciter includes an upper plate, a lower plate, and the piezoelectric ceramic sheet. The upper plate has a circular cavity, and the lower plate has a circular groove. The sidewall of the circular groove has a stepped surface, and the piezoelectric ceramic sheet is located on the stepped surface. The upper plate has a stepped protrusion corresponding to the stepped surface, which can press the piezoelectric ceramic sheet onto the stepped surface. One side of the circular groove has a connecting outlet, and the multi-segment wing has a pipe connecting to the connecting outlet. The upper plate and the lower plate are connected by bolts.

[0015] Preferably, an O-ring is also provided on one side of the piezoelectric ceramic sheet.

[0016] The present invention achieves the following technical effects compared to the prior art:

[0017] The synthetic jet control multi-segment wing lift enhancement device provided by this invention has a mounting groove in the middle of the multi-segment wing, located near the trailing edge of the wing. A synthetic jet mechanism is installed within the mounting groove, with the jet direction tangential to the sidewall of the multi-segment wing. Driven by an alternating power supply, the synthetic jet mechanism periodically generates blowing and suction airflow at the outlet position. The jet, tangential to the wall, flows towards the recirculation zone, injecting momentum into the shear layer. This enhances the boundary layer's resistance to flow separation induced by the adverse pressure gradient, delays flow separation, effectively reduces the size of the recirculation zone, and thus improves the aerodynamic characteristics of the multi-segment wing. Furthermore, activating the synthetic jet mechanism at different angles of attack and flap deflection angles can achieve varying degrees of lift enhancement, improving the aerodynamic performance of the multi-segment wing. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 is a schematic diagram of the structure of the synthetic jet control multi-segment wing lift enhancement device provided by the present invention;

[0020] Figure 2 is a schematic diagram of the internal structure of the synthetic jet exciter;

[0021] Figure 3 is a schematic diagram of the lift coefficient of the synthetic jet control multi-segment wing lift enhancement device in this invention;

[0022] Figure 4 is a schematic diagram of the synthetic jet vortex structure in this invention;

[0023] Figure 5 is a schematic diagram of the vortex structure formed by the interaction between the synthetic jet and the incoming flow in this invention;

[0024] Figure 6 is a time-averaged streamline diagram before the multi-segment airfoil synthetic jet control in this invention;

[0025] Figure 7 is a time-averaged streamline diagram after multi-segment airfoil composite jet control in this invention;

[0026] Figure 8 is a schematic diagram of the arrangement scheme of the synthetic jet control multi-segment wing lift enhancement device in this invention;

[0027] Figure 9 is a schematic diagram of the modular synthetic jet control multi-segment wing lift enhancement device in this invention;

[0028] Figure 10 is a schematic diagram of the synthetic jet exciter in Figure 9;

[0029] Figure 11 is a cross-sectional view at point AA in Figure 10;

[0030] In the diagram: 1-Main wing, 2-Leading edge slat, 3-Lower cover plate, 4-Leading edge flap, 5-Synthetic jet exciter, 6-Circular cavity, 7-Threaded hole, 8-Piezoelectric ceramic sheet, 9-O-ring, 10-Middle plate, 11-Wire groove, 12-Outlet pipe, 13-Upper plate, 14-Lower plate. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The purpose of this invention is to provide a synthetic jet-controlled multi-segment wing lift enhancement device to solve the technical problem of poor aerodynamic performance of existing wings across the entire angle of attack range.

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] As shown in Figures 1-11, this embodiment provides a synthetic jet control lift enhancement device for a multi-segment wing, including a multi-segment wing and a synthetic jet mechanism. A mounting groove is provided in the middle of the multi-segment wing, and the mounting groove is located near the trailing edge of the wing. The synthetic jet mechanism is installed in the mounting groove, and the jet direction of the synthetic jet mechanism is tangential to the sidewall of the multi-segment wing. The synthetic jet mechanism is driven by an alternating power supply, thereby periodically generating blowing and suction airflows at the outlet position. The jet, tangential to the wall, flows towards the recirculation zone, injecting momentum into the shear layer, thereby improving the boundary layer's ability to resist flow separation induced by the adverse pressure gradient, delaying flow separation, effectively reducing the size of the recirculation zone, and thus improving the aerodynamic characteristics of the multi-segment wing. Furthermore, at different angles of attack and different flap deflection angles, activating the synthetic jet mechanism can achieve different degrees of lift enhancement, control flow separation at the slats or flaps to improve the flow state, provide higher lift for the wing, and improve the aerodynamic performance of the multi-segment wing.

[0035] Specifically, the multi-segment wing includes a main wing 1, a leading-edge slat 2, a trailing-edge flap 4, and a lower cover plate 3. The mounting slot is opened on the lower end face of the middle part of the main wing 1. The lower cover plate 3 is connected to the mounting slot by bolts and encapsulates the synthetic jet mechanism in the mounting slot. The leading-edge slat 2 and the trailing-edge flap 4 are respectively installed on the leading edge and trailing edge of the main wing 1.

[0036] The connection between the main wing 1 and the trailing edge flap 4 is arc-shaped, and the jet outlet of the synthetic jet mechanism is located at the connection between the main wing 1 and the trailing edge flap 4.

[0037] The synthetic jet mechanism includes a synthetic jet driver and multiple synthetic jet exciters 5. The synthetic jet driver is used to drive each synthetic jet exciter 5 to work. The synthetic jet driver includes a signal generator and a voltage amplifier. The signal generator generates an electrical signal with a certain waveform and frequency. The voltage amplifier amplifies the amplitude of the electrical signal. The synthetic jet exciter 5 is equipped with a piezoelectric ceramic plate 8.

[0038] The synthetic jet exciter 5 includes a circular cavity 6, an outlet pipe 12, a piezoelectric ceramic sheet 8, and a middle plate 10. The circular cavity 6 is located on the inner bottom surface of the mounting groove. One end of the outlet pipe 12 is connected to the circular cavity 6, and the other end extends to the trailing edge of the multi-segment wing. An annular step is provided on the side wall of the circular cavity 6. The piezoelectric ceramic sheet 8 is located on the annular step. An annular protrusion is provided on the middle plate 10 at the position corresponding to the annular step. A circular through hole is formed in the annular protrusion and communicates with the circular cavity 6. The annular protrusion is embedded in the annular step and presses down on the piezoelectric ceramic sheet 8. The diameter of the annular protrusion is slightly smaller than the inner diameter of the circular cavity 6 so that the middle plate 10 and the main wing 1 can fit tightly. The main wing 1, the middle plate 10, and the lower cover plate 3 are all connected together. As a preferred embodiment, each synthetic jet exciter 5 corresponds to a middle plate 10, and a circular through hole is provided on the middle plate 10 at the position corresponding to each synthetic jet exciter 5. An O-ring 9 is also provided on one side of the piezoelectric ceramic sheet 8. The piezoelectric ceramic sheet 8 is tightly attached to one side of the circular cavity 6 by the middle plate 10 and the O-ring 9, forming a slit cavity, namely the synthetic jet cavity. Under the excitation of alternating voltage, the piezoelectric ceramic sheet 8 reciprocates to compress and expand the gas in the cavity, forming a synthetic jet at the outlet pipe 12.

[0039] The lower cover plate 3 has an embedded groove at its upper end, the middle layer plate 10 is located in the embedded groove, and a wire groove 11 is provided on one side of the embedded groove. One end of the wire groove 11 is connected to the outside, and the other end of the wire groove 11 is connected to the embedded groove.

[0040] Multiple threaded holes 7 are provided in the mounting slot, on the middle plate 10, and on the lower cover plate 3. The mounting slot, the middle plate 10, and the lower cover plate 3 are connected by bolts passing through the threaded holes 7 located on different layers to maintain the original aerodynamic shape. The circular cavity 6, the outlet pipe 12, and the threaded holes 7 are all machined inside the main wing 1 and are evenly arranged along the span of the wing.

[0041] The outlet pipe 12 is a rectangular pipe. An O-ring 9 is also provided on one side of the piezoelectric ceramic plate 8.

[0042] In this embodiment, the principle of synthetic jet control for multi-segment wing lift enhancement is as follows:

[0043] During the blowing process of the synthetic jet exciter 5, vortex rings / pairs are gradually formed and move downstream under their own induced velocity; during the intake process, low-speed fluid near the outlet pipe 12 is drawn into the cavity. Since the vortex rings have developed to the downstream and will not be drawn in, a series of vortex rings / pairs are generated, which entrain a large amount of surrounding fluid, enhance the mixing of the jet with the surrounding flow field, thereby improving the boundary layer's ability to resist adverse pressure gradient, delaying flow separation, and improving the aerodynamic performance of the multi-stage airfoil.

[0044] The main structural dimensions involved in this embodiment are related to the experimental conditions and can be designed according to different wind tunnel test section sizes. The current design dimensions of the main structure are as follows:

[0045] Multi-segment wing: trailing edge flaps 4 with a deflection angle of 50°, span of 400mm, and chord length of 200mm.

[0046] Synthetic jet exciter 5: Circular cavity diameter 48mm, circular cavity height 2.5mm, outlet pipe 12 size 1mm×20mm, jet outlet position at 86% of chord length from the leading edge.

[0047] The piezoelectric ceramic sheet 8 has a diameter of 50mm, and the O-ring 9 has a wire diameter of 1.5mm.

[0048] In application, the synthetic jet exciter 5 can increase the lift coefficient of the multi-segment wing, thereby improving the lift of the multi-segment wing.

[0049] Figure 3 is a schematic diagram of the lift coefficient of the synthetic jet-controlled multi-segment wing lift enhancement device provided in this embodiment. The horizontal axis represents the angle of attack α, and the vertical axis represents the lift coefficient C. LIn this application, the excitation signal of the synthetic jet exciter 5 is a sine wave with an excitation frequency of 1kHz and a peak-to-peak voltage of 300V. As shown in Figure 3, compared to the case without synthetic jet control (white hollow line), after control by the synthetic jet exciter 5, the lift coefficient of the multi-segment wing is improved to varying degrees within the angle of attack range of 0° to 38°. Before the angle of attack of 22°, the lift coefficient shifts upward, indicating that the overall lift of the multi-segment wing has been improved; and the stall angle of attack is delayed from 22° to 24°, with the maximum lift coefficient increasing by 11.2%; after the stall angle of attack, the lift curve after control is still higher than that without control, and the lift enhancement effect is still very significant. It is worth noting that in this embodiment, the flap deflection angle is 50°. When the wing angle of attack is 30° to 40°, the local angle of attack of the trailing edge flap 4 is already at the limit of 80° to 90°. At this time, the flow separation at the trailing edge is extremely large, and the control of the synthetic jet is extremely difficult. Nevertheless, within the 30°–40° angle of attack range of the main wing 1, the lift coefficient still shows a slight increase, indicating that the synthetic jet control multi-segment wing lift enhancement device in this embodiment also has a good control effect at high angles of attack and large flap deflection angles. Therefore, in this embodiment, by activating the synthetic jet mechanism at the trailing edge of the multi-segment wing, the lift coefficient of the multi-segment wing body is improved across the entire angle of attack range, especially enhancing the aerodynamic performance of the multi-segment wing at high angles of attack and large flap deflection angles.

[0050] Figure 4 is a schematic diagram of the synthetic jet vortex structure in a static environment. It can be seen that a counter-rotating flow vortex pair is formed at the outlet, which can effectively enhance the mixing of the jet with the surrounding fluid.

[0051] Figure 5 shows a schematic diagram of the vortex structure under the interaction of the synthetic jet and the incoming flow. At the outlet, a pair of synthetic jet vortices are observed to form, inducing the incoming flow to deflect downwards. The upper vortex develops downstream, deforms and elongates, and gradually dissipates, enhancing the mixing effect between the jet and the incoming flow and injecting momentum into the boundary layer. The lower vortex stretches along the wall, directly injecting the high-momentum jet into the low-momentum recirculation region, and then alternately develops downstream with the wake vortex.

[0052] Figures 6 and 7 are schematic diagrams of the time-averaged streamlines of the airfoil before and after synthetic jet control. It can be seen that without control, the separation zone at the trailing edge is large and contains a high-intensity vortex pair. When the synthetic jet is activated, the separation zone size decreases significantly. The synthetic jet accelerates the flow upstream of the outlet, inducing the upward flow downwards; simultaneously, the vortex structure induced by the synthetic jet approaches the wall, inducing the downward wake vortex upwards. Therefore, the synthetic jet can disrupt the shear layer, inject momentum into the separation zone, effectively suppress the separation zone size, and improve the airfoil's lift coefficient.

[0053] Figure 8 is a schematic diagram of the arrangement scheme of the synthetic jet control multi-segment wing lift enhancement device provided in this embodiment. The synthetic jet exciter 5 can be arranged at the leading edge slat 2, or applied before and after the slotted flap, to suppress the separation flow and induce the attachment flow behind the slat or flap.

[0054] To facilitate installation and disassembly of the synthetic jet exciter 5, it is modularized. The structure of the control aircraft is shown in Figure 9. The synthetic jet exciter 5 includes an upper plate 13, a lower plate 14, and a piezoelectric ceramic sheet 8. The upper plate 13 has a circular cavity, and the lower plate 14 has a circular groove. A stepped surface is provided on the side wall of the circular groove, and the piezoelectric ceramic sheet 8 is located on the stepped surface. A stepped protrusion is provided on the upper plate 13 corresponding to the stepped surface, which presses the piezoelectric ceramic sheet 8 onto the stepped surface. A connecting outlet is provided on one side of the circular groove, and a pipe connecting to the connecting outlet is provided on the multi-segment wing. The upper plate 13 and the lower plate 14 are connected by bolts, thus sealing the piezoelectric ceramic sheet 8. An O-ring 9 is also provided on one side of the piezoelectric ceramic sheet 8. Taking a ceramic sheet with a diameter of 50mm as an example, the synthetic jet exciter 5 has a thickness of only 10mm, a width of 70mm, an adjacent spacing of 55mm, and a total length determined by the number of array elements. The synthetic jet exciter 5 has a small volume in the fuselage and can be installed inside the main wing 1 or the flap. The outlet position can be selected at 15-18% and 85-88% of the chord length from the leading edge.

[0055] Figures 10 and 11 show the modular synthetic jet actuator 5. The circular groove on the lower plate 14 and the piezoelectric ceramic plate 8 form the working chamber. The vibration and deformation of the piezoelectric ceramic plate 8 causes pressure changes in the gas within the working chamber, generating a synthetic jet at the outlet. The jet is guided towards the fuselage wall through a pipe in the fuselage. The resulting synthetic jet vortex interacts with the incoming flow, delaying flow separation on the fuselage surface and increasing lift. The modularity of the synthetic jet actuator 5 allows for independent replacement of both the piezoelectric ceramic plate 8 and the working chamber. For example, adjusting the chamber parameters can be done simply by replacing the lower plate 14, significantly reducing the cost of machining, modifying, and disassembling the wing.

[0056] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A synthetic jet-controlled multi-segment wing lift enhancement device, characterized in that: The system includes a multi-segment wing and a synthetic jet mechanism. The multi-segment wing has a mounting groove in its middle section, located near the trailing edge. The synthetic jet mechanism is installed within the mounting groove, and its jet direction is tangential to the sidewall of the multi-segment wing. The synthetic jet mechanism is driven by an alternating power supply. The multi-segment wing includes a main wing, leading-edge slats, trailing-edge flaps, and a lower cover plate. The mounting groove is located on the lower end face of the middle section of the main wing. The lower cover plate is bolted to the mounting groove, and the synthetic jet mechanism is mounted within it. The flow mechanism is encapsulated within the mounting slot, with the leading-edge slats and trailing-edge flaps respectively mounted on the leading and trailing edges of the main wing. The synthetic jet mechanism includes a synthetic jet driver and multiple synthetic jet actuators. The synthetic jet driver drives each of the synthetic jet actuators, and includes a signal generator and a voltage amplifier. Each synthetic jet actuator contains a piezoelectric ceramic plate. Each synthetic jet actuator includes a circular cavity, an outlet pipe, the piezoelectric ceramic plate, and a middle plate; the circular cavity is formed within the mounting slot. The inner bottom surface of the wing has one end of the outlet pipe connected to the circular cavity, and the other end extending to the trailing edge of the multi-segment wing. An annular step is provided on the side wall of the circular cavity, and the piezoelectric ceramic sheet is located on the annular step. An annular protrusion is provided on the middle plate corresponding to the position of the annular step. A circular through hole communicating with the circular cavity is formed within the annular protrusion. The annular protrusion is embedded in the annular step and presses down on the piezoelectric ceramic sheet. The main wing, the middle plate, and the lower cover plate are all connected together; or, the synthetic jet exciter... The device includes an upper plate, a lower plate, and the piezoelectric ceramic sheet. The upper plate has a circular cavity, and the lower plate has a circular groove. The side wall of the circular groove has a stepped surface, and the piezoelectric ceramic sheet is located on the stepped surface. The upper plate has a stepped protrusion corresponding to the stepped surface, which can press the piezoelectric ceramic sheet onto the stepped surface. One side of the circular groove has a connecting outlet, and the multi-segment wing has a pipe connecting to the connecting outlet. The upper plate and the lower plate are connected by bolts.

2. The synthetic jet-controlled multi-segment wing lift-enhancing device according to claim 1, characterized in that: The connection between the main wing and the trailing edge flap is arc-shaped, and the jet outlet of the synthetic jet mechanism is located at the connection between the main wing and the trailing edge flap.

3. The synthetic jet-controlled multi-segment wing lift-enhancing device according to claim 1, characterized in that: The upper end of the lower cover plate is provided with an embedding groove, the middle layer plate is located in the embedding groove, and a wire groove is provided on one side of the embedding groove. One end of the wire groove is connected to the outside, and the other end of the wire groove is connected to the embedding groove.

4. The synthetic jet-controlled multi-segment wing lift-enhancing device according to claim 1, characterized in that: Multiple threaded holes are provided in the mounting groove, the middle layer plate, and the lower cover plate. Bolts are used to connect the mounting groove, the middle layer plate, and the lower cover plate through the threaded holes located in different layers.

5. The synthetic jet-controlled multi-segment wing lift-enhancing device according to claim 1, characterized in that: The outlet pipe is a rectangular pipe.

6. The synthetic jet-controlled multi-segment wing lift-enhancing device according to claim 1, characterized in that: An O-ring is also provided on one side of the piezoelectric ceramic sheet.

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