A method for increasing wing lift and enhancing rudder effectiveness based on synthetic jets

Abstract

This application relates to a method for wing lift augmentation and rudder effectiveness enhancement based on synthetic jet, which belongs to the technical field of active flow control of aircraft. The method includes: using a power control system to convert the airborne high-voltage direct current signal of the aircraft into a high-voltage high-frequency alternating current signal, arranging the synthetic jet actuator near the trailing edge of the wing, and the actuator generates synthetic jets under the drive of the high-voltage high-frequency alternating current signal; the synthetic jets interact with the oncoming flow to control the wing, so as to achieve the purpose of wing lift augmentation and rudder effectiveness enhancement. The core component in this method is the synthetic jet actuator, which has strong control ability, all-electric control, low energy consumption, high energy utilization rate, fast response speed, compact structure, light weight, does not require any air source pipelines, is very easy to achieve integrated design, and there is no problem of ballast failure, solving the engineering bottleneck problems of high energy consumption, large volume, heavy weight, affecting engine performance, and difficult to achieve integrated design in the prior art.

Description

Technical Field

[0001] The present application relates to the technical field of active flow control for aircraft, and particularly to a method for wing lift augmentation and rudder effectiveness enhancement based on synthetic jets. Background Art

[0002] When an aircraft conducts flight control, the wing and the control surface need to cooperate. There are often situations where the lift is insufficient at a certain operating point or the efficiency of the control surface is low. The ideas for solving such problems are divided into two types - passive flow control and active flow control. Passive flow control does not input energy from the outside, but only changes the aerodynamic shape of the wing, thereby improving the aerodynamic force distribution. This type of method is relatively simple and is widely used in engineering, but it lacks flexibility and cannot be adjusted according to the actual working conditions, and additional drag will be generated during cruising, and the cost-effectiveness is not high. Active flow control can, without changing the aerodynamic shape, only apply control at local sensitive points in the flow field to change the global flow field pattern, thereby improving the aerodynamic performance of the wing, and can effectively solve the problems of insufficient lift or insufficient rudder effectiveness at typical operating points.

[0003] Existing active jet generation devices need to generate jets with sufficient intensity through methods such as engine bleed air, backpack air source, axial flow fan, etc. However, such devices have high energy consumption and require complex pipeline designs, increasing the volume and weight of the system and the complexity of system integration; at the same time, engine bleed air will weaken the net thrust and load capacity of the engine, and there are risks of pipeline leakage and out-of-control during parking. Generally speaking, although the currently widely used active flow control means have considerable control capabilities, the cost-effectiveness is relatively low, and the engineering cycle is generally long. Summary of the Invention

[0004] Based on this, it is necessary to provide a method for wing lift augmentation and rudder effectiveness enhancement based on synthetic jets in view of the above technical problems.

[0005] A method for wing lift augmentation and rudder effectiveness enhancement based on synthetic jets, the method comprising:

[0006] Using a power control system to convert the airborne high-voltage direct current signal of the aircraft into a high-voltage high-frequency alternating current signal.

[0007] Arranging a synthetic jet actuator near the trailing edge of the wing, and the synthetic jet actuator generates synthetic jets under the drive of the high-voltage high-frequency alternating current signal.

[0008] The synthetic jets interact with the oncoming flow to control the wing, achieving the purpose of wing lift augmentation and rudder effectiveness enhancement.

[0009] In one embodiment, a synthetic jet actuator is arranged near the trailing edge of the wing. Driven by a high-voltage high-frequency alternating current signal, the synthetic jet actuator generates a synthetic jet, including:

[0010] The synthetic jet actuator is arranged near the trailing edge of the wing. The synthetic jet actuator forms a synthetic jet with a velocity of up to 200 m / s at the outlet. The synthetic jet includes two high-energy jets with opposite phases and mutual relay, which has a coupled enhancement control effect on the flow field and has the ability to control high-subsonic and transonic flow fields.

[0011] In one embodiment, the synthetic jet interacts with the oncoming flow to control the wing, achieving the purpose of wing lift augmentation and rudder effectiveness enhancement, including:

[0012] The synthetic jet interacts with the oncoming flow to form a pair of low-pressure recirculation zones with opposite rotation directions at the trailing edge of the wing, increasing the pressure difference between the front and rear on the upper surface, enhancing the flow velocity on the upper surface of the wing, moving the leading-edge stagnation point downward, increasing the effective angle of attack, forcing the leading-edge suction and the negative pressure on the suction surface to increase, and moving the trailing-edge stagnation point downward and backward, enhancing the wing circulation and equivalent camber, and increasing the lift.

[0013] A recirculation zone is formed between the two outlets of the synthetic jet actuator, hindering the flow on the lower surface, increasing the positive pressure before the jet orifice, increasing the lift and the nose-down moment, and achieving the purpose of wing lift augmentation and rudder effectiveness enhancement.

[0014] In one embodiment, the synthetic jet actuator is integrally designed with the wing and does not change the original aerodynamic shape of the wing.

[0015] In one embodiment, the synthetic jet actuator is a synthetic jet actuator with a single membrane, double cavity, and double outlet structure.

[0016] In one embodiment, the jet outlets of the synthetic jet actuator are arranged along the pressure surface, and the distance between the two outlets of the synthetic jet actuator is adjusted autonomously according to preset requirements.

[0017] In one embodiment, the outlet throat of the synthetic jet actuator is of a constricted shape, a divergent shape, or a constricted-divergent shape.

[0018] In one embodiment, the outlet jet angle of the synthetic jet actuator varies between 0 and 180 degrees.

[0019] In one embodiment, the outlet shape of the synthetic jet actuator is circular, elliptical, triangular, rectangular, annular, or an array of different shapes.

[0020] In one embodiment, the arrangement positions, numbers, and spacings of the synthetic jet actuators in the flow direction and spanwise direction are all autonomously adjusted according to preset requirements.

[0021] The above-mentioned method for enhancing wing lift and rudder effectiveness based on synthetic jets includes: using a power control system to convert the airborne high-voltage direct current signal of the aircraft into a high-voltage high-frequency alternating current signal, arranging a fully electrically controllable synthetic jet actuator near the trailing edge of the wing. The synthetic jet actuator generates synthetic jets under the drive of the high-voltage high-frequency alternating current signal. The synthetic jets interact with the oncoming flow to control the wing, achieving the purpose of enhancing wing lift and rudder effectiveness. The core component used in this method is the synthetic jet actuator, which has strong control ability, full electrical control, low energy consumption, high energy utilization rate, fast response speed, compact structure, light weight, does not require any air source pipelines, is extremely easy to realize integrated design, and does not have the problem of ballast failure, solving the engineering bottleneck problems of high energy consumption, large volume, heavy weight, affecting engine performance, and difficult to realize integrated design in the prior art. Description of the Drawings

[0022] Figure 1 Schematic diagram of the overall structure of the aircraft and the installation of the synthetic jet actuator in one embodiment;

[0023] Figure 2 Schematic flow diagram of the method for enhancing wing lift and rudder effectiveness based on synthetic jets in one embodiment;

[0024] Figure 3 Schematic diagram of different outlet spacings of the synthetic jet actuator in another embodiment;

[0025] Figure 4 Schematic diagram of the outlet throat shape of the synthetic jet actuator in another embodiment;

[0026] Figure 5 Schematic diagram of different outlet jet angles of the synthetic jet actuator in another embodiment;

[0027] Figure 6 Schematic diagram of the outlet cross-sectional shape of the synthetic jet actuator in another embodiment;

[0028] Figure 7 Schematic diagram of the spanwise and flow direction arrangements of the synthetic jet actuator in another embodiment;

[0029] Figure 8 Schematic diagram of the changes in the aerodynamic characteristics of the wing before and after applying control in another embodiment, where (a) is the lift coefficient and its change amount, (b) is the drag coefficient and its change amount, (c) is the pitching moment coefficient and its change amount, and (b) is the lift-to-drag ratio and its change amount;

[0030] Figure 9 For the comparison of the flow fields before and after applying control at an angle of attack of 0 degrees in another embodiment, where (a)-(c) are the velocity contour, tail velocity contour, and tail pressure contour before applying control respectively, and (d)-(f) are the velocity contour, tail velocity contour, and tail pressure contour after applying control respectively;

[0031] Figure 10 For the comparison of the pressure distributions before and after applying control at an angle of attack of 0 degrees in another embodiment. Detailed implementation manners

[0032] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application 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 only used to explain the present application, and are not used to limit the present application.

[0033] In one embodiment, as Figure 1 shown in the schematic diagram of the overall structure of the aircraft and the installation of the synthetic jet actuator, it includes a wing 1, a synthetic jet actuator 2 and a power control system 3; the wing 1 is the application control object of this method. As Figure 2 shown, a method for increasing the lift of the wing and enhancing the rudder effectiveness based on synthetic jets is provided, and this method includes the following steps:

[0034] Step 200: Use the power control system to convert the airborne high-voltage direct current signal of the aircraft into a high-voltage high-frequency alternating current signal.

[0035] Specifically, the power control system can convert the airborne high-voltage direct current signal into a high-voltage high-frequency alternating current signal to drive the synthetic jet actuator to work. The power control system is installed inside the wing, generally in the middle position of the wing.

[0036] The high-voltage direct current signal is equivalent to the signal provided by the aircraft's own power supply.

[0037] Step 202: Arrange the synthetic jet actuator near the trailing edge of the wing. The synthetic jet actuator generates synthetic jets under the drive of the high-voltage high-frequency alternating current signal.

[0038] Specifically, the synthetic jet actuator is arranged near the trailing edge of the wing. It can generate two high-speed jets, namely synthetic jets, under the drive of the alternating current signal generated by the power control system. The two jets have opposite phases and have the effects of mutual relay and coupling enhancement.

[0039] The response speed of the synthetic jet actuator is extremely fast, and the stable flow field establishment time is on the order of milliseconds.

[0040] The synthetic jet actuator is a fully electrically controlled zero - mass jet actuator that does not require any air - source pipelines and has low power consumption. The power consumption of a single actuator is less than 5W, showing high potential for engineering applications.

[0041] The outlet length and width of the synthetic jet actuator can be adjusted according to actual requirements to achieve the target control effect. The cavity volume and shape of the synthetic jet actuator can be optimized according to actual requirements to achieve the best control effect. The spatial layout position, jet outlet parameters, and actuator cavity parameters of the synthetic jet actuator can be adaptively adjusted and optimized according to actual engineering requirements, broadening the scope of engineering applications. This method has important application value in the fields of aircraft lift augmentation and rudder effectiveness enhancement.

[0042] Step 204: The synthetic jet interacts with the oncoming flow to control the wing, achieving the purpose of wing lift augmentation and rudder effectiveness enhancement.

[0043] Specifically, under the interaction between the synthetic jet and the oncoming flow, a pair of low - pressure recirculation zones with opposite rotation directions are formed at the trailing edge of the wing, increasing the pressure difference between the front and rear of the upper surface, enhancing the flow velocity on the upper surface, causing the leading - edge stagnation point to move downward, increasing the effective angle of attack, forcing the leading - edge suction and the negative pressure on the suction surface to increase; at the same time, the trailing - edge stagnation point moves downward and backward, effectively enhancing the wing circulation and equivalent camber, and increasing the lift. In addition, a recirculation zone is formed between the two outlets of the synthetic jet actuator, hindering the flow on the lower surface, increasing the positive pressure before the jet outlet, increasing the lift and nose - down moment, and having a good effect on lift augmentation and rudder effectiveness enhancement.

[0044] In the above - mentioned method for wing lift augmentation and rudder effectiveness enhancement based on synthetic jets, the method includes: using a power control system to convert the on - board high - voltage direct - current signal of the aircraft into a high - voltage high - frequency alternating - current signal, arranging the fully electrically controllable synthetic jet actuator near the trailing edge of the wing, and the synthetic jet actuator generates a synthetic jet under the drive of the high - voltage high - frequency alternating - current signal; the synthetic jet interacts with the oncoming flow to control the wing, achieving the purpose of wing lift augmentation and rudder effectiveness enhancement. The core component used in this method is the synthetic jet actuator, which has strong control ability, fully electric control, low energy consumption, high energy utilization rate, fast response speed, compact structure, light weight, does not require any air - source pipelines, is extremely easy to achieve integrated design, and does not have the problem of ballast failure, solving the engineering bottleneck problems of high energy consumption, large volume, heavy weight, affecting engine performance, and difficult to achieve integrated design in the existing technology.

[0045] In one embodiment, step 202 includes: arranging a synthetic jet actuator near the trailing edge of the wing, the synthetic jet actuator forming a synthetic jet with a velocity up to 200 m / s at the outlet, the synthetic jet including two high-energy jets with opposite phases and relaying each other, having a coupled enhancement control effect on the flow field and possessing the control ability for high subsonic and transonic flow fields.

[0046] In one embodiment, step 202 includes: the synthetic jet interacts with the oncoming flow, forming a pair of low-pressure recirculation zones with opposite rotation directions at the trailing edge of the wing, increasing the front and rear pressure differences on the upper surface, enhancing the flow velocity on the upper surface of the wing, causing the leading-edge stagnation point to move downward, increasing the effective angle of attack, forcing the leading-edge suction and the negative pressure on the suction surface to increase, the trailing-edge stagnation point to shift downward and backward, enhancing the wing circulation and equivalent camber, and increasing the lift; a recirculation zone is formed between the two outlets of the synthetic jet actuator, hindering the flow on the lower surface, enhancing the positive pressure before the jet orifice, increasing the lift and the nose-down moment, achieving the purpose of wing lift augmentation and rudder effectiveness enhancement.

[0047] In one embodiment, the synthetic jet actuator is integrally designed with the wing without changing the original aerodynamic shape of the wing.

[0048] Specifically, the synthetic jet actuator has a compact structure and light weight, and is very easy to achieve an integrated design. After the integrated design, there are no protrusions on the wing surface, and no form drag and thermal protection problems will be caused.

[0049] In one embodiment, the synthetic jet actuator is a synthetic jet actuator with a single-membrane double-chamber double-outlet structure.

[0050] Specifically, the synthetic jet actuator with a single-membrane double-chamber double-outlet structure has a high energy utilization efficiency and avoids the problem of diaphragm ballast failure.

[0051] In one embodiment, the jet outlets of the synthetic jet actuator are arranged along the pressure surface, and the distance between the two outlets of the synthetic jet actuator is adjusted autonomously according to preset requirements.

[0052] Specifically, the schematic diagram of different outlet distances of the synthetic jet actuator is as Figure 3 shown. The distance between the two outlets of the synthetic jet actuator can be adaptively adjusted according to actual control requirements to achieve the best control effect.

[0053] In one embodiment, the jet outlet throat of the synthetic jet actuator is of a convergent shape, a divergent shape or a convergent-divergent form.

[0054] Specifically, the schematic diagram of the jet outlet throat shape of the synthetic jet actuator is as Figure 4As shown in the figure. The outlet throat of the synthetic jet actuator can be designed as a convergent shape, a divergent shape, or a convergent-divergent shape according to the actual control ability requirements. In applications, different types of outlet throats can be selected according to the actual control requirements to endow the jet with different control abilities and achieve the best regulation of aerodynamic characteristics.

[0055] In one embodiment, the outlet jet angle of the synthetic jet actuator varies between 0 and 180 degrees.

[0056] Specifically, a schematic diagram of different outlet jet angles of the synthetic jet actuator is shown in Figure 5 As shown in the figure. The outlet jet angle of the synthetic jet actuator can vary between 0 and 180 degrees. In applications, the jet angle can be adjusted and optimized according to the actual control requirements to achieve the best regulation of aerodynamic characteristics.

[0057] In one embodiment, the outlet shape of the synthetic jet actuator is circular, elliptical, triangular, rectangular, annular, or an array of different shapes.

[0058] Specifically, a schematic diagram of some shapes of the outlet cross-section of the synthetic jet actuator is shown in Figure 6 As shown in the figure. The outlet of the synthetic jet actuator can be circular, elliptical, triangular, rectangular, annular, or any other shape. In applications, different outlet configurations can be selected according to the actual flow conditions of the wing to endow the jet with different three-dimensional characteristics and ensure the achievement of the best control effect.

[0059] The outlet shape of the synthetic jet actuator can also be designed as an array of different shapes according to needs to endow the jet with different three-dimensional characteristics and ensure the achievement of the best control effect.

[0060] In one embodiment, the arrangement positions, numbers, and spacings of the synthetic jet actuators in the flow direction and spanwise direction are all autonomously adjusted according to preset requirements.

[0061] Specifically, the arrangement positions, numbers, and spacings of the synthetic jet actuators in the flow direction and spanwise direction can be optimized according to actual needs to achieve the best regulation of the wing lift and moment.

[0062] A schematic diagram of the spanwise and flow direction arrangements of the synthetic jet actuators is shown in Figure 7 As shown in the figure. Figure 7 One circle represents one synthetic jet actuator. The synthetic jet actuators are distributed parallel in the flow direction. In applications, the optimal spacings and numbers of the flow direction and spanwise arrangements can be selected according to actual needs to achieve the best regulation of the wing lift and moment.

[0063] In a verification embodiment, the control effect of this invention was simulated by numerical methods, as shown in Figures 8 - 10Shown Figure 8 Schematic diagrams of the changes in the aerodynamic characteristics of the wing before and after applying control, where (a) is the lift coefficient and its change, (b) is the drag coefficient and its change, (c) is the pitching moment coefficient and its change, and (b) is the lift-drag ratio and its change, Figure 8 where C L is the lift, ΔC L is the change in lift after applying synthetic jet control, C d is the drag, ΔC d is the change in drag after applying synthetic jet control, C m is the pitching moment, ΔC m is the change in pitching moment after applying synthetic jet control, Nocontrol represents before applying synthetic jet control, control represents after applying synthetic jet control, and AOA represents the angle of attack of the aircraft; Figure 9 Comparison of the flow fields before and after applying control at an angle of attack of 0 degrees, where (a)-(c) are the velocity contour, tail velocity contour (a partial enlargement of (a)), and tail pressure contour before applying control respectively, and (d)-(f) are the velocity contour, tail velocity contour (a partial enlargement of (d)), and tail pressure contour after applying control respectively; Figure 10 Comparison of the pressure distributions before and after applying control at an angle of attack of 0 degrees. Figures 8 - 10 It is clearly shown that after applying flow control, the lift, nose-down moment, and drag of the airfoil increase, and the lift-drag ratio is effectively improved at medium lift coefficients, having good lift augmentation and rudder effectiveness enhancement control capabilities; observing the flow field characteristics before and after control, it can be found that under the interaction of the synthetic jet with the oncoming flow, a pair of low-pressure recirculation zones with opposite rotation directions are formed at the trailing edge of the wing, increasing the front and rear pressure differences on the upper surface, increasing the flow velocity on the upper surface, moving the leading edge stagnation point downward, increasing the effective angle of attack, forcing the leading edge suction and the negative pressure on the suction surface to increase; at the same time, the trailing edge stagnation point moves downward and backward, effectively increasing the wing circulation and equivalent camber, and increasing the lift. In addition, a recirculation zone is formed between the two outlets of the synthetic jet actuator, hindering the flow on the lower surface, increasing the positive pressure before the jet orifice, thereby increasing the lift and nose-down moment.

[0064] It should be understood that although Figure 2 the steps in the flowchart of Figure 2At least a part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages do not necessarily need to be completed at the same moment, but can be executed at different moments. The execution order of these sub-steps or stages does not necessarily need to be sequential, but can be executed alternately or in turns with at least a part of other steps or sub-steps or stages of other steps.

[0065] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as within the scope described in this specification.

[0066] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A method for increasing the lift of a wing and enhancing the rudder effect based on synthetic jets, characterized in that, the method includes: using a power control system to convert the airborne high-voltage direct current signal of the aircraft into a high-voltage high-frequency alternating current signal; arranging the synthetic jet actuator near the trailing edge of the wing, and its jet outlet is arranged along the pressure surface. The synthetic jet actuator generates synthetic jets under the drive of the high-voltage high-frequency alternating current signal. Among them, the synthetic jet actuator is a single-membrane double-chamber double-outlet structure; the synthetic jets interact with the oncoming flow to control the wing, achieving the purpose of increasing the lift of the wing and enhancing the rudder effect. Among them, the synthetic jets interact with the oncoming flow to form a pair of low-pressure recirculation zones with opposite rotation directions at the trailing edge of the wing, increasing the front and rear pressure differences on the upper surface, increasing the flow velocity on the upper surface of the wing, moving the leading-edge stagnation point downward, increasing the effective angle of attack, forcing the leading-edge suction and the negative pressure on the suction surface to increase, moving the trailing-edge stagnation point downward and backward, increasing the wing circulation and equivalent camber, increasing the lift, forming a recirculation zone between the two outlets of the synthetic jet actuator, hindering the flow on the lower surface, increasing the positive pressure before the jet orifice, increasing the lift and the pitching moment, achieving the purpose of increasing the lift of the wing and enhancing the rudder effect.

2. The method according to claim 1, characterized in that, arranging the synthetic jet actuator near the trailing edge of the wing, and the synthetic jet actuator generates synthetic jets under the drive of the high-voltage high-frequency alternating current signal, including: arranging the synthetic jet actuator near the trailing edge of the wing, and the synthetic jet actuator forms synthetic jets with a velocity of up to 200 m / s at the outlet. The synthetic jets include two high-energy jets with opposite phases and mutual relay, having a coupled and enhanced control effect on the flow field and having the ability to control the high-subsonic and transonic flow fields.

3. The method according to claim 1, characterized in that, the synthetic jet actuator is integrally designed with the wing and does not change the original aerodynamic shape of the wing.

4. The method according to claim 3, characterized in that, the distance between the two outlets of the synthetic jet actuator is autonomously adjusted according to preset requirements.

5. The method according to claim 3, characterized in that, the outlet throat of the synthetic jet actuator is of a convergent shape, a divergent shape or a convergent-divergent shape.

6. The method according to claim 3, characterized in that, the outlet jet angle of the synthetic jet actuator varies between 0 and 180 degrees.

7. The method according to claim 3, characterized in that, the outlet shape of the synthetic jet actuator is circular, elliptical, triangular, rectangular, annular or an array of different shapes.

8. The method according to claim 3, characterized in that, the arrangement positions, numbers and distances of the synthetic jet actuator in the flow direction and spanwise direction are all autonomously adjusted according to preset requirements.

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