A method of designing a high-lift airfoil, a high-lift airfoil and an aircraft

Abstract

This invention discloses a lift-enhancing wing surface design method, a lift-enhancing wing surface, and an aircraft, relating to the field of aerodynamic shape design technology. The lift-enhancing wing surface design method includes the following steps: S1: Extending from the leading edge of the wing root chord at a predetermined sweep angle within the wing surface design plane until it intersects with the forebody shock wave surface, forming a sweep angle chord. S2: Extending a predetermined length backward along the forebody shock wave surface at the intersection of the sweep angle chord and the forebody shock wave surface, forming a backward sweep angle chord. S3: Setting a wingtip chord parallel to the wing root chord at the other end of the backward sweep angle chord, and determining the lengths of the wing root chord and the wingtip chord according to the designed wing area. This solves the problem in existing technologies using triangular or trapezoidal wing surfaces, where a larger wing area is required to obtain greater lift.

Description

Technical Field

[0001] This invention relates to the field of aerodynamic shape design technology, specifically to a lift-enhancing wing surface design method, a lift-enhancing wing surface, and an aircraft. Background Technology

[0002] Lift-enhancing surfaces are wing surfaces on an aircraft that can increase lift during flight. In hypersonic aircraft, in order to provide higher lift with the smallest possible size and wing area, it is necessary to improve the structural design of the wing surfaces.

[0003] In existing technologies, triangular or trapezoidal wing surfaces are generally used, with the leading-edge shock wave developing outwards towards the aircraft, carrying away some of the airflow energy. However, this presents the problem of requiring a larger wing area to obtain greater lift. Summary of the Invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a lift-enhancing wing surface design method, a lift-enhancing wing surface and an aircraft, which can solve the problem that in the prior art, when using triangular or trapezoidal wing surfaces, a larger wing area is required to obtain greater lift.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] Firstly, this solution provides a lift-enhancing wing surface design method, including:

[0007] Extend from the leading edge of the wing root chord within the wing surface design plane at the set sweep angle until it intersects with the shock wave surface of the forebody, forming a sweep angle chord;

[0008] At the intersection of the forward sweep chord and the forebody shock surface, a set length is extended backward along the forebody shock surface to form the backward sweep chord.

[0009] A wingtip chord parallel to the wing root chord is set at the other end of the sweep angle chord, and the lengths of the wing root chord and wingtip chord are determined according to the designed wing area.

[0010] In some alternative schemes, the optimal lift-to-drag ratio angle of attack is determined based on the set airflow Mach number and the shape of the aircraft, and the corresponding three-dimensional shape of the forebody shock surface is determined based on the optimal lift-to-drag ratio angle of attack.

[0011] In some alternative schemes, after extending a predetermined length backward along the forebody shock surface at the intersection of the forward sweep chord and the forebody shock surface to form a backward sweep chord, the intersection of the forward sweep chord and the backward sweep chord is rounded to meet the requirements of structural load-bearing and aerodynamic thermal protection.

[0012] In some alternative schemes, a wingtip chord parallel to the wing root chord is set at the other end of the sweep angle chord. After determining the lengths of the wing root chord and the wingtip chord according to the design wing area, the negative pressure zone is removed along the isobaric line on the side of the lift-enhancing wing surface according to the wing surface pressure distribution.

[0013] In some alternative schemes, the set sweep angle is determined according to the formula: α = 30 + 7.5 × (ma - 3);

[0014] Where α is the forward sweep angle and ma is the Mach number of the airflow.

[0015] In some alternative solutions, the set length must satisfy the requirement that the chord width of the lift-enhancing wing surface with sweep angle is less than or equal to the chord width of the lift-enhancing wing surface with sweep angle.

[0016] In some alternative designs, the wing surface design plane has a set angle of dihedral.

[0017] In some alternative configurations, the leading edge point of the wing root chord is located within a set distance range between the main body of the aircraft and the nose of the aircraft.

[0018] Secondly, this solution also provides a lift-enhancing wing surface, which is designed using any of the above-mentioned lift-enhancing wing surface design methods.

[0019] Thirdly, this solution also provides an aircraft that includes the aforementioned lift-enhancing wing surfaces.

[0020] Compared with the prior art, the advantages of this invention are as follows: In this design, the wing extends from the leading edge of the wing root chord at a predetermined sweep angle within the wing surface design plane until it intersects with the forebody shock surface, forming a sweep chord; at the intersection of the sweep chord and the forebody shock surface, it extends rearward along the forebody shock surface for a predetermined length, forming a backward sweep chord; at the other end of the backward sweep chord, a wingtip chord parallel to the wing root chord is provided, and the lengths of the wing root chord and wingtip chord are determined according to the designed wing area. This solves the problem in the prior art where a larger wing area is required to obtain greater lift when using triangular or trapezoidal wing surfaces. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a flowchart illustrating the lift-enhancing wing surface design method in an embodiment of the present invention;

[0023] Figure 2 This is a top view of the lifting wing surface and the aircraft in an embodiment of the present invention;

[0024] Figure 3 This is a front view schematic diagram of the lifting wing surface and the aircraft in an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of a conventional trapezoidal airfoil in an embodiment of the present invention;

[0026] Figure 5 This is a bottom view of the lifting wing surface and the isobars of the aircraft in an embodiment of the present invention;

[0027] Figure 6 This is a bottom view of the isobars of a conventional trapezoidal wing surface in an embodiment of the present invention;

[0028] In the diagram: 1. Forward sweep chord; 2. Backward sweep chord; 3. Wing root chord; 4. Wing tip chord; 5. Main body of the aircraft; 6. Nose of the aircraft; 7. Front sweep chord side of the lift-enhancing wing surface; 8. Backward sweep chord side of the lift-enhancing wing surface; 9. Negative pressure zone. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] Firstly, such as Figure 1 and Figure 2 As shown, the present invention provides a method for designing lift-enhancing airfoils, comprising:

[0032] S1: Extend from the leading edge of the wing root chord 3 within the wing surface design plane at the set forward sweep angle until it intersects with the forebody shock wave surface, forming the forward sweep angle chord 1.

[0033] In this embodiment, the wing surface design plane refers to the plane where the lift-enhancing wing surface is located. The wing root chord 3 refers to the chord where the lift-enhancing wing surface contacts the aircraft body 5. The forebody shock surface refers to the outer edge of the strong compression wave in the supersonic airflow at the aircraft nose 6.

[0034] S2: At the intersection of the forward sweep angle chord 1 and the forebody shock surface, extend backward along the forebody shock surface by a set length to form the backward sweep angle chord 2.

[0035] In this embodiment, "backward" refers to the side away from the aircraft's nose 6.

[0036] S3: Set a wingtip chord 4 parallel to the wing root chord 3 at the other end of the sweep angle chord 2, and determine the lengths of the wing root chord 3 and the wingtip chord 4 according to the designed wing area.

[0037] In this embodiment, the leading edge of the wing, namely the forward sweep chord 1 and the backward sweep chord 2, is placed within the shock wave compression zone of the aircraft's forebody, ensuring a strong high-pressure zone is generated on the lower surface of the wing while reducing leading-edge drag. A portion of the high-pressure airflow from the wing's leading edge is directed to the inner lower surface of the aircraft, thereby increasing the pressure in the wing-body interference zone and achieving a lift-enhancing effect.

[0038] In some optional embodiments, before extending from the leading edge of the wing root chord 3 within the wing surface design plane at a set forward sweep angle until it intersects with the forebody shock surface to form the forward sweep angle chord 1, the optimal lift-to-drag ratio angle of attack is determined based on the aircraft's set airflow Mach number and aircraft shape, and the corresponding three-dimensional shape of the forebody shock surface is determined based on the optimal lift-to-drag ratio angle of attack.

[0039] In this embodiment, the set airflow Mach number of the aircraft is determined according to the actual flight requirements of the aircraft. In this embodiment of the invention, 3 ≤ set airflow Mach number ≤ 7. The optimal lift-to-drag ratio angle of attack is determined by CFD (Computational Fluid Dynamics) or engineering methods based on the set airflow Mach number and the shape of the aircraft, and the corresponding three-dimensional shape of the forebody shock surface is determined based on the optimal lift-to-drag ratio angle of attack.

[0040] In some optional embodiments, after extending a predetermined length backward along the forebody shock surface at the intersection of the forward sweep chord 1 and the forebody shock surface to form the backward sweep chord 2, the intersection of the forward sweep chord 1 and the backward sweep chord 2 is rounded to meet the requirements of structural load-bearing and aerodynamic heat protection.

[0041] In this embodiment, the rounding radius should be as small as possible while meeting the requirements of structural load-bearing capacity and aerodynamic heat protection, in order to obtain a better lifting effect.

[0042] In some optional embodiments, a wingtip chord 4 parallel to the wing root chord 3 is provided at the other end of the sweep angle chord 2. After determining the lengths of the wing root chord 3 and the wingtip chord 4 according to the designed wing area, the negative pressure zone portion 9 is removed along the isobaric line on the sweep angle chord side 8 of the lift-enhancing wing surface according to the wing surface pressure distribution.

[0043] In this embodiment, a straight line passing through the intersection of the forward sweep chord 1 and the backward sweep chord 2 and parallel to the wing root chord 3 divides the lift-enhancing wing surface into two parts. The part containing the forward sweep chord 1 is the forward sweep chord side 7 of the lift-enhancing wing surface, and the part containing the backward sweep chord 2 is the backward sweep chord side 8 of the lift-enhancing wing surface. Based on the wing surface pressure distribution, the negative pressure region 9 is removed along the isobars on the backward sweep chord side 8 of the lift-enhancing wing surface, thereby improving the aerodynamic efficiency of the lift-enhancing wing surface. If there is no negative pressure region, no treatment is required.

[0044] In some optional embodiments, the set sweep angle is determined according to the formula: α = 30 + 7.5 × (ma - 3);

[0045] Where α is the forward sweep angle and ma is the Mach number of the airflow.

[0046] In this embodiment, the sweep angle is set to be within the range of 30°≤α≤60°.

[0047] In some optional embodiments, the set length must satisfy the requirement that the width of the sweep angle chord side 8 of the lift-enhancing wing surface is less than or equal to the width of the sweep angle chord side 7 of the lift-enhancing wing surface.

[0048] In this embodiment, the width of the sweep angle chord side 8 of the lift-enhancing wing surface being less than or equal to the width of the sweep angle chord side 7 of the lift-enhancing wing surface enables the lift-enhancing wing surface to have better aerodynamic performance.

[0049] like Figure 3 As shown, in some optional embodiments, the wing surface design plane has a set angle of dihedral.

[0050] In this embodiment, the angle is set to 20 degrees. By setting a dihedral angle on the lift-enhancing wing surface, the shock wave traction effect of the forward sweep chord 1 and the backward sweep chord 2 is improved.

[0051] In some alternative embodiments, the leading edge point of the wing root chord 3 is located within a set distance range between the aircraft body 5 and the aircraft head 6.

[0052] When the wing area is equal and the aircraft is set to Mach 5, such as Figure 5 and Figure 6 As shown, CFD simulation can yield results such as... Figure 4 The pressure in the wing-body interference zone of the conventional trapezoidal wing shown is 58571.4 Pa, while the pressure in the wing-body interference zone of the lift-enhancing wing with forward sweep angle is 63928.6 Pa. The pressure is increased by 9%, and the corresponding optimal lift-to-drag ratio and lift are both increased by approximately 5%.

[0053] In summary, this invention extends from the leading edge of the wing root chord within the wing design plane at a predetermined sweep angle until it intersects with the forebody shock surface, forming a sweep angle chord. At the intersection of the sweep angle chord and the forebody shock surface, it extends rearward along the forebody shock surface for a predetermined length, forming a backward sweep angle chord. A wingtip chord parallel to the wing root chord is provided at the other end of the backward sweep angle chord, and the lengths of the wing root chord and wingtip chord are determined based on the designed wing area. This solves the problem in existing technologies using triangular or trapezoidal wing surfaces, where a larger wing area is required to obtain greater lift.

[0054] This invention enables aircraft to achieve higher lift and lift-to-drag ratios than conventional delta wings and trapezoidal wings with the same wing area. Under the same root chord length and span constraints, a shock-driven lift-enhancing wing surface with a forward sweep angle can achieve a larger wing area, thereby providing greater lift. The lift-enhancing wing surface structure and manufacturing process designed using this invention are simple and suitable for supersonic and hypersonic aircraft employing flat-plate wing surface lift enhancement.

[0055] Secondly, the present invention also provides a lift-enhancing wing surface, which is designed using any of the above-described lift-enhancing wing surface design methods.

[0056] Thirdly, the present invention also provides an aircraft comprising the aforementioned lift-enhancing wing surfaces.

[0057] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0058] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0059] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for designing lift-enhancing airfoils, characterized in that, include: Extend from the leading edge of the wing root chord within the wing surface design plane at the set sweep angle until it intersects with the shock wave surface of the forebody, forming a sweep angle chord; At the intersection of the forward sweep chord and the forebody shock surface, a set length is extended backward along the forebody shock surface to form the backward sweep chord. A wingtip chord parallel to the wing root chord is set at the end of the sweep angle chord that is far from the intersection point mentioned above, and the lengths of the wing root chord and the wingtip chord are determined according to the designed wing area.

2. The lift-enhancing wing surface design method as described in claim 1, characterized in that, Before the forward sweep angle chord is formed by extending from the leading edge of the wing root chord within the wing surface design plane to intersect with the forebody shock wave surface, the optimal lift-to-drag ratio angle of attack is determined based on the aircraft's set airflow Mach number and aircraft shape. The corresponding three-dimensional shape of the forebody shock wave surface is then determined based on the optimal lift-to-drag ratio angle of attack.

3. The lift-enhancing wing surface design method as described in claim 1, characterized in that, After extending a set length backward along the forebody shock surface at the intersection of the forward sweep chord and the forebody shock surface to form the backward sweep chord, the intersection of the forward sweep chord and the backward sweep chord is rounded to meet the requirements of structural load-bearing and aerodynamic heat protection.

4. The lift-enhancing wing surface design method as described in claim 1, characterized in that, A wingtip chord parallel to the wing root chord is set at the end of the sweep angle chord that is far from the above intersection point. After determining the lengths of the wing root chord and the wingtip chord according to the design wing area, the negative pressure area is removed along the isobaric line on the side of the lift-enhancing wing surface according to the wing surface pressure distribution.

5. The lift-enhancing wing surface design method as described in claim 1, characterized in that, According to the formula: α = 30 + 7.5 × (ma) 3) Determine the set forward sweep angle; Where α is the forward sweep angle and ma is the Mach number of the airflow.

6. The lift-enhancing wing surface design method as described in claim 1, characterized in that, The specified length must satisfy the requirement that the chord width of the lift-enhancing wing surface with the sweep angle is less than or equal to the chord width of the lift-enhancing wing surface with the sweep angle.

7. The lift-enhancing wing surface design method as described in claim 1, characterized in that, The wing surface design plane has a set angle of dihedral.

8. The lift-enhancing wing surface design method as described in claim 1, characterized in that, The leading edge point of the wing root chord is located within a set distance range between the main body of the aircraft and the nose of the aircraft.

9. A lift-enhancing wing surface, characterized in that, It is designed using any one of the lift-enhancing wing surface design methods as described in claims 1-8.

10. An aircraft, characterized in that, It includes the lift-enhancing wing surface as described in claim 9.

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