An active flow control rudder

Abstract

The present invention provides an active flow control rudder, which is connected to the tail of an aircraft wing. The active flow control rudder comprises: an upper rudder and an upper rudder actuating mechanism, the upper rudder and the upper rudder actuating mechanism are connected to each other, and the upper rudder is controlled by the upper rudder actuating mechanism and moves up and down with the central axis of the wing as the axis; a lower rudder and a lower rudder actuating mechanism, the lower rudder and the lower rudder actuating mechanism are connected to each other, and the lower rudder is controlled by the lower rudder actuating mechanism and moves up and down with the central axis of the wing as the axis. Under the condition of the same demand for course control moment, the active flow control rudder can have a smaller rudder surface area, thereby reducing the structural mass and improving the performance of the aircraft; the active flow control rudder can provide a higher course control moment, thereby improving the course maneuverability and wind resistance of the aircraft, achieving the purpose of increasing the control moment of the course movement and improving the rudder efficiency of the split rudder.

Description

Technical Field

[0001] This specification relates to the technical field of aircraft rudders, and particularly to an active flow control rudder. Background Art

[0002] The rudder is an important part of a flying wing aircraft, generally located outside the elevons, and can provide a yaw control moment, thereby generating the effects of yaw stability augmentation and drag increment. Currently, most rudders of flying wing layouts generate moments using drag, so they are also called drag rudders. However, the magnitude of drag is very small compared to lift. If lift is used to generate control forces, the magnitude of the control forces can be greatly increased, thereby improving the rudder efficiency, which is beneficial to reducing the effective area of the rudder surface, reducing the structural mass, and improving the aerodynamic efficiency.

[0003] Active flow control technology has become a major focus in the development of future aircraft due to its advantages in lift augmentation, drag reduction, stealth, noise reduction, and attitude control. On the basis of not affecting the aircraft performance, adding active flow control technology to the design optimization of a split rudder can further improve the performance of the split rudder.

[0004] Therefore, using lift to generate control forces and combining active flow control to further optimize the rudder efficiency of a split rudder is an effective approach. Summary of the Invention

[0005] In view of this, the embodiments of this specification provide an active flow control rudder to solve the problems of insufficient rudder efficiency and non-linearity of the yaw control efficiency of the rudder surface caused by using drag control in traditional drag rudders.

[0006] The embodiments of this specification provide the following technical solutions:

[0007] An active flow control rudder is connected to the tail of an aircraft wing. The active flow control rudder includes:

[0008] An upper rudder and an upper rudder actuator, the upper rudder and the upper rudder actuator are connected to each other, and the upper rudder is controlled by the upper rudder actuator and moves up and down with the central axis of the wing as the axis;

[0009] A lower rudder and a lower rudder actuator, the lower rudder and the lower rudder actuator are connected to each other, and the lower rudder is controlled by the lower rudder actuator and moves up and down with the central axis of the wing as the axis.

[0010] Further, the active flow control rudder further includes an internal pipeline and a Y-shaped jet groove. The internal pipeline is arranged inside the wing, and the Y-shaped jet groove is arranged inside the active flow control rudder. The internal pipeline and the Y-shaped jet groove are interconnected.

[0011] Furthermore, the Y-shaped jet groove includes a first air inlet and a first jet groove. The first jet groove is arranged between the upper rudder actuating mechanism and the lower rudder actuating mechanism. The first jet groove introduces air flow from the air outlet end of the internal pipeline through the first air inlet.

[0012] Furthermore, the Y-shaped jet groove further includes a second jet groove, a first air outlet, a third jet groove and a second air outlet. The first jet groove, the second jet groove and the third jet groove are interconnected through an intersection point. The first air outlet is arranged below the upper rudder, and the second air outlet is arranged above the lower rudder. A part of the air flow flows out from the first air outlet through the second jet groove, and another part of the air flow flows out from the second air outlet through the third jet groove.

[0013] Furthermore, the first air outlet and the second air outlet are symmetrically distributed along the center line of the wing.

[0014] Furthermore, the included angle between the second jet groove and the third jet groove is adjustable.

[0015] Furthermore, the active flow control rudder further includes a micro-compressor. The micro-compressor is arranged inside the wing, and the air outlet end of the micro-compressor is interconnected with the air inlet end of the internal pipeline.

[0016] Furthermore, both the air output volume and the air output pressure of the micro-compressor are adjustable.

[0017] Furthermore, the micro-compressor is arranged around the turbine of the aircraft engine.

[0018] Furthermore, the upper rudder actuating mechanism and the lower rudder actuating mechanism are electric actuators or hydraulic actuators.

[0019] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above technical solutions adopted in the embodiments of this specification at least include:

[0020] Compared with the traditional split rudder, under the condition of the same demand for course control moment, the active flow control rudder can have a smaller rudder surface area, thereby reducing the structural mass and improving the aircraft performance; if the area of the split rudder remains unchanged, the active flow control rudder can provide a higher course control moment, thereby improving the course maneuverability and wind resistance of the aircraft, achieving the purpose of increasing the control moment of the course movement and improving the rudder efficiency of the split rudder. Description of the Drawings

[0021] To more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings required for the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0022] Figure 1 Schematic diagram of aerodynamic force generated by the airflow on the rudder surface of the rudder;

[0023] Figure 2 Schematic diagram of the course moment generated by the split rudder;

[0024] Figure 3 Schematic diagram of aerodynamic force on the traditional split rudder;

[0025] Figure 4 Schematic diagram of aerodynamic force on the active flow control rudder;

[0026] Figure 5 Schematic diagram of the deflection of the active flow control rudder;

[0027] Figure 6 Schematic diagram of the non-deflection of the active flow control rudder.

[0028] Explanation of reference numerals: 1, micro-compressor; 2, internal pipeline; 3, Y-shaped jet groove; 301, first air inlet; 302, first air outlet; 303, second air outlet; 304, first jet groove; 305, second jet groove; 306, third jet groove; 4, upper rudder; 5, lower rudder; 6, upper rudder actuator; 7, lower rudder actuator; 8, wing. Detailed implementation manners

[0029] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0030] The following illustrates the implementation manners of the present application through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts belong to the scope of protection of the present application.

[0031] Note that the following description pertains to various aspects of embodiments within the scope of the appended claims. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using other structures and / or functionality in addition to one or more of the aspects set forth herein.

[0032] It should also be noted that the diagrams provided in the following embodiments merely illustrate the basic concept of this application schematically. Only the components related to this application are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in its actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0033] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0034] According to the principles of aerodynamics, the aerodynamic forces generated by the airflow on a rudder surface similar to a wing include drag D and lift L. As Figure 2 shown, the schematic diagram of the cracking rudder generating a heading moment. Among them, L represents the aerodynamic lift generated on the rudder surface; D represents the aerodynamic drag generated on the rudder surface.

[0035] The magnitude of the aerodynamic drag generated by the rudder surface is:

[0036] The magnitude of the aerodynamic lift generated by the rudder surface is:

[0037] In formulas (1) and (2): ρ is the air density; v is the velocity of the airflow relative to the rudder surface, which represents the oncoming flow velocity of the distant air and is equal to the airspeed during the flight of the aircraft; S is the reference area of the rudder surface; C D is the drag coefficient; C L is the lift coefficient. The drag coefficient C D is usually on the order of 0.01, and the lift coefficient C L is usually on the order of 0.10.

[0038] The split rudder is an important way of the heading control rudder surface of tailless aircraft such as the flying wing layout and the blend wing body (BWB) layout. It is generally located outside the elevon and can provide the heading control moment for the aircraft.

[0039] As Figure 3 shown, the principle of generating the heading control moment is as follows: after the split rudder deflects, aerodynamic drag and aerodynamic lift are generated on it. Since there is a spanwise distance between the rudder surface and the aircraft's center of gravity, the heading control moment can be generated through the aerodynamic drag and aerodynamic lift generated on it. The heading moment generated by the traditional split rudder is related to the following parameters. x cg is the position of the aircraft's center of gravity; L b is the lateral vertical distance from the resultant force point of the rudder surface to the aircraft's center of gravity, that is, the control arm of the rudder surface; D represents the aerodynamic drag generated by the rudder surface.

[0040] As Figure 4 shown, the aerodynamic force on the traditional split rudder is related to the following parameters. v represents the oncoming flow velocity of the far - away air, which is equal to the airspeed during the aircraft's flight; D up represents the aerodynamic drag generated by the rudder surface of the upper rudder 4; D down represents the aerodynamic drag generated by the rudder surface of the lower rudder 5; Since the aerodynamic force generated by the airflow on the traditional split rudder is mainly aerodynamic drag and the aerodynamic lift is almost zero, the resultant force F it receives is F = D. Therefore, the traditional split rudder is also called the drag - type rudder. As Figure 4 shown in the rear part (the airflow dead zone), the airflow only flows through the outer surface, and the middle part of the rudder surface is the airflow dead zone where the airflow velocity is almost zero. Therefore, only drag is generated and no lift is generated.

[0041] The following will describe the technical solutions provided by the embodiments of the present application with reference to the accompanying drawings.

[0042] As Figure 1As shown in the figure, the overall structure of the jet-type active flow control rudder of a flying wing aircraft includes the rudder of the flying wing aircraft, and the tail is a split-type structure. The split-type structure is divided into the upper rudder 4 and the lower rudder 5. The upper rudder 4 is connected to the wing through the upper rudder actuator 6. The lower rudder 5 is connected to the wing 8 through the lower rudder actuator 7. Both the upper rudder actuator 6 and the lower rudder actuator 7 are electric actuators, hydraulic actuators, or any other form of mechanical actuating device. A micro compressor 1 is arranged inside the wing to extract high-pressure air flow from the high-pressure turbine of the engine, and the gas after pressure adjustment is used as the air source for active flow control. In addition, the high-pressure air introduced from the high-pressure turbine of the engine saves the energy consumed by separately generating gas. The Y-shaped jet groove 3 is installed inside the rudder and is arranged between the upper rudder 4 and the lower rudder 5. The Y-shaped jet groove 3 is connected to the micro compressor 1 through the internal pipeline 2 to realize the active flow control of the air flow between the upper rudder 4 and the lower rudder 5. Through the above structure, the rudder efficiency of the aircraft is enhanced, and the non-linearity of the course control rudder efficiency is weakened.

[0043] As Figure 6 shown, when the aircraft is in the cruise state, the upper rudder 4 and the lower rudder 5 of the jet-type active flow control rudder are closed to ensure the streamlined shape of the wing. At this time, the micro compressor 1 is in the standby state, there is no flowing air inside the Y-shaped jet groove 3, and the Y-shaped jet groove 3 is wrapped in the gap closed by the upper rudder 4 and the lower rudder 5.

[0044] As Figure 1 shown, when the aircraft needs to change its course, the upper rudder actuator 6 and the lower rudder actuator 7 start to work to realize the deflection of the upper rudder 4 and the lower rudder 5. After the rudder surfaces of the upper rudder 4 and the lower rudder 5 are opened at a certain angle, the micro compressor 1 starts to work, draws air from the engine, and transports the air flow to the Y-shaped jet groove 3 through the internal pipeline 2. The Y-shaped jet groove 3 divides the air flow into upper and lower parts and blows it to the inner surface of the split rudder surface. After the jet is turned on, the aerodynamic force generated on the upper and lower split rudders increases in the horizontal direction, thereby increasing the control moment of the course movement and improving the rudder efficiency of the split rudder. Compared with the traditional split rudder, under the condition of the same course control moment requirement, the active flow control rudder can have a smaller rudder surface area, thereby reducing the structural mass and improving the performance of the aircraft; if the area of the split rudder remains unchanged, the active flow control rudder can provide a higher course control moment, thereby improving the course maneuverability and wind resistance of the aircraft.

[0045] The additional aerodynamic force generated by the jet on the upper and lower rudders is as Figure 5 shown, in the figure, v jet represents the jet velocity of the nozzle; D jet,up represents the aerodynamic drag generated on the rudder surface of the upper rudder 4 due to the jet action; Ljet,up Denotes the aerodynamic lift generated by the rudder surface of the upper rudder 4 due to the jet action; D up Denotes the aerodynamic drag generated by the rudder surface of the upper rudder 4 without jet action; D jet,down Denotes the aerodynamic drag generated by the rudder surface of the lower rudder 5 due to the jet action; L jet,down Denotes the aerodynamic lift generated by the rudder surface of the lower rudder 5 due to the jet action; D down Denotes the aerodynamic drag generated by the rudder surface of the lower rudder 5 without jet action. It is observed that the additional aerodynamic force increases the control force of the course motion along the horizontal direction, thus increasing the course control moment, improving the rudder efficiency of the split rudder, facilitating the reduction of the effective area of the rudder surface, reducing the structural mass and improving the aerodynamic efficiency. At the same time, the non-linearity of the rudder surface course control moment is improved by adjusting different jet flows.

[0046] The rudder in this embodiment enables the active control of the flow control inside the rudder by adding a jet device composed of a micro-compressor 1, an internal pipeline 2 and a Y-shaped jet groove 3 on the basis of the traditional split rudder.

[0047] The Y-shaped jet groove 3 includes a first air inlet 301 and a first jet groove 304. The first jet groove 304 is arranged between the upper rudder actuator 6 and the lower rudder actuator 7. The first jet groove 304 introduces air flow from the air outlet end of the internal pipeline 2 through the first air inlet 301. The Y-shaped jet groove 3 further includes a second jet groove 305, a first air outlet 302, a third jet groove 306 and a second air outlet 303. The first jet groove 304, the second jet groove 305 and the third jet groove 306 are interconnected through a intersection point. The first air outlet 302 is arranged below the upper rudder 4, and the second air outlet 303 is arranged above the lower rudder 5. A part of the air flow flows out from the first air outlet 302 through the second jet groove 305, and another part of the air flow flows out from the second air outlet 303 through the third jet groove 306.

[0048] The micro-compressor 1 extracts the high-pressure gas generated by the turbine of the engine. After pressure adjustment, it is transmitted to the first air inlet 301 of the Y-shaped jet groove 3 through the internal pipeline 2. The first air outlet 302 and the second air outlet 303 are symmetrically distributed along the center line of the wing 8. After the upper rudder 4 and the lower rudder 5 are opened, the Y-shaped jet groove 3 jets high-pressure and high-speed air to the upper rudder 4 through the first air outlet 302 and to the lower rudder 5 through the second air outlet 303, increasing the air speed between the rudder surfaces of the upper rudder 4 and the lower rudder 5 of the split rudder. Therefore, the lift generated by the air flow on the split rudder is increased. As Figure 5 , at this time, the resultant force F on the rudder surface = D jet +L jet+D. As can be seen from Equation (1) and Equation (2), the resultant force generated on the jet-type split rudder is greater than that on the traditional split rudder. Therefore, on the premise that the course control arm L b remains unchanged, the course control moment generated by the active flow control rudder is greater, that is, the jet-type split rudder has higher control efficiency. Therefore, on the premise that the required value of the control moment is certain, the area of the control rudder surface required is smaller, thus reducing the structural mass of the aircraft. Or when the area and deflection angle of the control rudder surface are the same, the active flow control rudder can generate a greater control moment, making the aircraft easier to control and having a faster response speed.

[0049] The included angle between the second jet groove 305 and the third jet groove 306 is a fixed included angle between 0 degrees and 180 degrees, and can be designed according to parameters such as the deployable included angle of the upper rudder 4 and the lower rudder 5, and the size of the aircraft tail fin.

[0050] In some other embodiments, the included angle between the second jet groove 305 and the third jet groove 306 can be adjusted according to the angles at which the upper rudder 4 and the lower rudder 5 open during flight.

[0051] In some other embodiments, the size of the Y-shaped jet groove 3, that is, the lengths of the first jet groove 304, the second jet groove 305, and the third jet groove 306, can be optimized and designed according to parameters such as the sizes of the upper rudder 4 and the lower rudder 5 of the specific aircraft, and the deployable included angle between the upper rudder 4 and the lower rudder 5.

[0052] In some other embodiments, the micro-compressor 1 can adjust the air output volume and air output pressure, and can provide different air flows for the upper rudder 4 and the lower rudder 5 of different sizes of different models of aircraft.

[0053] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the method embodiments described later, since they correspond to the system, the description is relatively simple, and the relevant parts can refer to the partial description of the system embodiments.

[0054] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An active flow control rudder is connected to the tail of an aircraft wing (8), and is characterized in that, The active flow control rudder includes: an upper rudder (4) and an upper rudder actuator (6), the upper rudder (4) and the upper rudder actuator (6) are connected to each other, and the upper rudder (4) is controlled by the upper rudder actuator (6) and moves up and down with the central axis of the wing (8) as the axis; a lower rudder (5) and a lower rudder actuator (7), the lower rudder (5) and the lower rudder actuator (7) are connected to each other, and the lower rudder (5) is controlled by the lower rudder actuator (7) and moves up and down with the central axis of the wing (8) as the axis; The active flow control rudder further includes an internal duct (2) and a Y-shaped jet groove (3), the internal duct (2) is arranged inside the wing (8), the Y-shaped jet groove (3) is arranged inside the active flow control rudder, and the internal duct (2) and the Y-shaped jet groove (3) are communicated with each other.

2. The active flow control rudder according to claim 1, characterized in that, The Y-shaped jet groove (3) includes a first air inlet (301) and a first jet groove (304), the first jet groove (304) is arranged between the upper rudder actuator (6) and the lower rudder actuator (7), and the first jet groove (304) introduces air flow from the air outlet end of the internal duct (2) through the first air inlet (301).

3. The active flow control rudder according to claim 2, characterized in that, The Y-shaped jet groove (3) further includes a second jet groove (305), a first air outlet (302), a third jet groove (306) and a second air outlet (303), the first jet groove (304), the second jet groove (305) and the third jet groove (306) are communicated with each other through a intersection point, the first air outlet (302) is arranged below the upper rudder (4), the second air outlet (303) is arranged above the lower rudder (5), a part of the air flow flows out from the first air outlet (302) through the second jet groove (305), and another part of the air flow flows out from the second air outlet (303) through the third jet groove (306).

4. The active flow control rudder according to claim 3, characterized in that, The first air outlet (302) and the second air outlet (303) are symmetrically distributed along the center line of the wing (8).

5. The active flow control rudder according to claim 3, characterized in that, The included angle between the second jet groove (305) and the third jet groove (306) is adjustable.

6. The active flow control rudder according to claim 1, characterized in that, The active flow control rudder further includes a micro compressor (1), the micro compressor (1) is arranged inside the wing (8), and the air outlet end of the micro compressor (1) is communicated with the air inlet end of the internal duct (2).

7. The active flow control rudder according to claim 6, characterized in that, Both the air output volume and the air output pressure of the micro compressor (1) are adjustable.

8. The active flow control rudder according to claim 6, characterized in that, The micro compressor (1) is arranged around the turbine of the aircraft engine.

9. The active flow control rudder according to claim 1, characterized in that, The upper rudder actuator (6) and the lower rudder actuator (7) are electric actuators or hydraulic actuators.

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