CN113722815A

CN113722815A - Design method for separating surface of folding wing without changing aerodynamic shape

Info

Publication number: CN113722815A
Application number: CN202110840511.4A
Authority: CN
Inventors: 何玉鑫; 王昌银; 李广利; 田中伟; 常思源; 崔凯
Original assignee: Guangdong Aerospace Science And Technology Research Institute; Institute of Mechanics of CAS
Current assignee: Guangdong Aerospace Science And Technology Research Institute; Institute of Mechanics of CAS
Priority date: 2021-07-24
Filing date: 2021-07-24
Publication date: 2021-11-30
Anticipated expiration: 2041-07-24
Also published as: CN113722815B

Abstract

The invention belongs to the technical field of aerospace aircraft folding wing structures, and discloses a method for designing a folding wing separation surface without changing aerodynamic appearance, which comprises the following steps: axial separation plane intersecting lines are established between symmetrical axial sections of respective sawtooth-shaped intersecting lines on the upper surface and the lower surface of the wing, and are designed based on the folding wing separation plane axial separation theorem and deduction, so that the outer wing does not interfere when rotating downwards around the inner wing; the axial sub-separation surface is a curved surface which is generated by adopting an intersection line of the axial separation surface and a zigzag intersection line and can ensure that the inner wing and the outer wing do not interfere when the outer wing rotates clockwise around the rotating shaft; the separating surface designed by the method does not need the shapes of the upper surface and the lower surface of the wing, namely, the aerodynamic shape is not changed, and no gap exists between the inner wing and the outer wing in the unfolded state of the folded wing, so that the loss of lift force caused by the seepage of airflow below the wing to the upper side can be avoided.

Description

Design method for separating surface of folding wing without changing aerodynamic shape

Technical Field

The invention belongs to the technical field of aerospace aircraft folding wing structures, and particularly relates to a design method of a folding wing separation surface without changing the aerodynamic appearance.

Background

Wings are the main source of lift for aircraft, modern aircraft designs aim to increase the wing area to obtain higher lift, however, the increased wingspan of aircraft causes great difficulty in storing and transporting the aircraft, and engineers try to replace a whole wing with a folded wing. When the aircraft is transported, stored and takes off for standby, the wings of the aircraft are in a folded state, and the wings enter an unfolded state and are locked during taking off or after taking off.

Common wing folding forms include in-plane folding, namely variable sweepback wings, variable sweepfront wings and telescopic wings, and out-plane folding, namely L-shaped folding, Z-shaped folding and the like.

The folding wing is divided into a fixed inner wing and a rotatable and foldable outer wing, a separating surface is called as a separating surface when the folding wing is in an unfolded state, in order to reduce the change of aerodynamic appearance and the overflow of airflow below the wing as much as possible, the gap is designed to be reduced as much as possible, and the aerodynamic appearance is not damaged.

The existing folding wing scheme or the large gap between the inner wing and the outer wing needs to be added with a cover plate to reduce aerodynamic loss, such as an F35C fighter plane; or the design of the separating surface is not considered at all, such as the patent CN 103287570Z.

Disclosure of Invention

The invention provides a method for designing a separating surface of a folding wing without changing aerodynamic appearance in order to solve the technical problem, and aims to solve the problem that aerodynamic loss is reduced by adding a cover plate in the existing folding wing scheme or the problem that gaps between an inner wing and an outer wing are large.

In order to solve the technical problem, the invention provides the following technical scheme:

a method for designing a separating surface of a folding wing without changing aerodynamic configuration comprises the following steps:

step one, establishing an overlapping area of an inner wing and an outer wing along an axis direction;

determining the position of the axis of the rotating shaft and the approximate positions of the separating surfaces of the inner wing and the outer wing on two sides of the axis according to the size design requirements of the inner wing and the outer wing in the overlapping area, and establishing an auxiliary envelope line;

establishing intersecting lines of the separating surface and the upper surface and the lower surface of the wing on the auxiliary envelope line, wherein the intersecting lines adopt a sawtooth type design, the sizes of the sawtooth number, the interval and the like can be independently designed, and the sawtooth type intersecting lines consist of a plurality of axial sections parallel to the axis and a plurality of transverse sections vertical to the axis;

establishing axial separation surface intersecting lines between symmetrical axial sections of respective sawtooth-shaped intersecting lines on the upper surface and the lower surface of the wing; the symmetrical axial sections comprise an upper axial section and a lower axial section which are on the same vertical plane, wherein one axial section is a curve and the upper and lower symmetrical axial sections after the curve is projected;

step five, respectively establishing a plurality of transverse sub-separation surfaces between the upper surface and the lower surface of the wing on the transverse section of the zigzag intersection line of the inner wing and the outer wing;

step six, respectively establishing a plurality of axial sub-separation surfaces between the upper surface and the lower surface of the wing on the axial section of the zigzag intersection line of the inner wing and the outer wing;

and step seven, splicing the transverse and longitudinal sub-separation surfaces of the inner wing and the outer wing to obtain a complete separation surface configuration.

Step eight, dividing the complete wing by using the complete separating surface to obtain an inner wing and an outer wing, and establishing a rotating shaft along an axis;

the method is characterized in that:

the intersecting line of the axial separating surfaces is designed based on the folding wing separating surface axial separating theorem and deduction, and the intersecting line is reasonably designed, so that the outer wing does not interfere when rotating downwards around the inner wing; the transverse sub-separation surface is a vertical plane formed by cutting a transverse section of a zigzag intersection line of the upper surface and the lower surface of the wing; the axial sub-separating surface is a curved surface which is generated by adopting the intersecting line of the axial separating surface and the zigzag intersecting line and can ensure that the inner wing and the outer wing do not interfere when the outer wing rotates clockwise around the rotating shaft.

For any axial separating surface intersecting line S, the starting point of the intersecting line S is point A, the end point is point Z, the axis of the rotating shaft is taken as a pole O, and the point passes through

Of rays of

Establishing a polar coordinate system as a polar axis, and taking the anticlockwise direction as the positive direction; the starting point A and the end point Z are respectively positioned on the symmetrical axial sections of the upper and lower surface sawtooth type intersecting lines; when the point on the outer wing meets the condition that the polar diameter r (theta) (0-theta-AOZ) is a monotone non-decreasing function, the separation surface generated by the intersection line S and the sawtooth-shaped intersection line can ensure that the outer wing does not interfere when rotating clockwise around the rotating shaft;

the intersecting line S of the axial separating surfaces comprises a type I, the three circular arcs use a point O as a pole O, and the radii of the three circular arcs are different.

The intersecting line S of the axial separating surfaces comprises a type II, and a curve S, namely a straight line segment AZ, falls on a normal line of the A point polar diameter OA.

The axial separating surface intersecting line S comprises a type III: three fold line type separating surface intersecting lines.

The axial separating surface intersecting line S comprises a type IV: the intersection line of the circular arc and the linear mixed type separating surface.

Advantageous effects of the invention

1. The invention provides a design method of a separating surface of a folding wing, the separating surface designed according to the method does not need the shapes of the upper surface and the lower surface of the wing, namely, the aerodynamic shape is not changed, and no gap exists between an inner wing and an outer wing in the unfolding state of the folding wing, so that the problem that the lifting force is lost due to the fact that airflow below the wing seeps to the upper side can be avoided.

2. The separating surface designed by the method provided by the invention can ensure that the outer wing does not interfere with the inner wing when rotating, and the method can also be used for judging whether the motion interference occurs or not in the existing folding wing separating surface scheme without motion simulation, so that the design time can be greatly saved.

3. The invention provides a method for cutting a whole wing profile by using a separating surface to separate an inner wing and an outer wing, which can ensure that the joint of the inner wing and the outer wing has no gap, thereby preventing air flow below the wings from seeping above the wings and reducing aerodynamic power loss, and belongs to the protection range of the patent.

4. The upper and lower surfaces of the inner wing and the outer wing designed by the invention are completely attached without a groove boss structure, and the aerodynamic appearance is not changed; the inner wing and the outer wing designed by the invention are completely occluded at the separation surface without gaps, so that the air flow below the wings can be prevented from seeping above the wings, and the aerodynamic loss is avoided; the designed separating surface ensures that the outer wing freely rotates downwards around the shaft without interference. The invention provides a design method of a non-interference separating surface, and a plurality of types of configurations, rather than a plurality of simple separating surface examples, thereby having general guiding significance. The scheme provided by the invention can be used for verifying whether the existing separating surface design is reasonable or not, and can judge whether the interference exists or not without using simulation software for motion simulation, so that the design time can be greatly reduced. The invention provides a separation surface design method with a limiting plate structure, and the limiting plate can be used for balancing the pneumatic load on the outer wing, so that the requirement of a folding wing locking mechanism on balancing high pneumatic load is reduced, and the difficulty of mechanism design is reduced.

Drawings

FIG. 1 is an exterior view of a folding wing and its separating surface without changing aerodynamic configuration.

FIG. 2 is a schematic diagram of the design of the parting plane.

FIG. 3 is a schematic diagram of the nature of the separating surface.

FIG. 4 shows a circular arc type parting surface (type I).

FIG. 5. straight separating surface (type II).

FIG. 6 shows a first embodiment of a broken line type parting surface (type III).

FIG. 7 shows a second embodiment of a broken line type parting surface (type III).

FIG. 8 shows a third example of a hybrid separating surface of arc and broken line (type IV).

Fig. 9 shows a fourth example of a hybrid separating surface (v-shaped) of a circular arc and a straight line.

FIG. 10 shows a fifth example of a hybrid separating surface of arc and broken line (type IV).

Fig. 11. six examples of the mixed type separating surface (type iv) of the circular arc and the broken line.

Fig. 12 shows a seventh example of a hybrid separating surface (type iv) of a circular arc and a broken line.

Fig. 13. envelope of the separating surface.

FIG. 14 is a schematic view of the intersection of the separation plane and the upper surface of the airfoil.

FIG. 15 is a schematic view of a parting plane.

FIG. 16 shows the inner and outer wings and the shaft cut from the parting plane.

Fig. 17 example one: the structure schematic diagram of the folding wing with the I-type and IV-type mixed-lapping separating surfaces is adopted.

Fig. 18 is a detailed structural diagram of the first embodiment.

Fig. 19 example two: the structure schematic diagram of the folding wing with the IV-type and II-type mixed-lapping separating surfaces is adopted.

Fig. 20 is a detailed structural diagram of example two.

Wherein, 1, a fixed part (called an inner wing) of the wing; 2. a foldable portion of the wing (called the outer wing); 3. a rotating shaft; 4. the intersection of the separation plane with the cross section of the airfoil (hereinafter referred to as the separation plane curve); 5. the intersection of the separation plane and the upper surface of the airfoil; 6. the circle center of the section of the rotating shaft; 7. an arbitrary separating surface curve; 8. the two curves are spliced to form a separating surface curve; 9. a linear separating surface curve; 10. curve example one of the broken line type separating surface; 11. curve example two of the broken line type separating surface; 12. type iv separation surface curve example three; 13. curve example four of v-type separating surface; 14. type iv parting surface curve example five; 15. type iv parting surface curve example six; 16. type iv parting surface curve example seven; 17-19, the i-type separating surface curved surface of example one; 20. type iv separating surface curve of example one; 21. limiting plates of the inner wings; 22. the limiting groove of outer wing.

Detailed Description

The design principle of the intersecting line of the axial separating surfaces is as follows:

first, about the intersection line of the axial separating surfaces

The invention comprises an inner wing (wing fixing part) 1, an outer wing (wing rotatable part) 2, a rotating shaft 3, an axial separating surface intersecting line 4, an intersecting line 5 of a separating surface and the upper surface of the wing and the like. The cross line 5 adopts a sawtooth type design, and the transverse section of the sawtooth is vertical to the axis of the rotating shaft.

The separating surface of the inner wing and the outer wing is divided into an axial section and a transverse section, the lower surface of the wing is a plane, and the axis of the rotating shaft 3 of the folding wing is parallel to the lower surface of the wing and the symmetrical surfaces of the wings at two sides, so that the processing and the assembly are convenient.

The design of the inner wing separating surface and the outer wing separating surface comprises the design of an axial section separating surface and a transverse section separating surface.The difficulty lies in the shaft And designing a section separation surface.The axial segment separation plane is created by axial segments in the axial separation plane intersection and the zigzag intersection. The axial section parting surface is formed by extending the axial parting surface intersecting line between the upper side line and the lower side line to the other end along the opposite end of the upper side line and the lower side line, and the upper side line and the lower side line of the parting surface are axial sections of the zigzag intersecting line, so the axial section parting surface is called as the axial section parting surface.

The second, axial parting plane intersection line is generated according to a certain rule

As shown in fig. 1, the axial parting plane intersection line 4 is an arc line rather than a straight line vertical to the upper and lower sides; the generation according to a certain rule is as follows: the axial separating surface formed by the intersecting lines does not prevent the outer wing from being folded clockwise, or does not interfere with the outer wing when the outer wing is folded clockwise and rotates clockwise along the rotating shaft. Otherwise, if the intersection line is not generated according to a certain rule but is a straight line perpendicular to the upper and lower sides, that is, the intersection line 4 of the axial separating plane in fig. 1 is not an arc but a straight line perpendicular to the upper and lower sides, when the outer wing 2 is folded clockwise, the straight line perpendicular to the upper and lower sides interferes with the folding of the outer wing 2 or hinders the folding of the outer wing 2.

Third, full necessity proof of axial parting plane intersection 4

The invention provides a design method of an axial separating surface intersection line 4, which can ensure that the inner wing and the outer wing do not interfere when the outer wing 2 rotates clockwise around a rotating shaft 3. Referring to FIG. 2, the cross section of the airfoil has an intersection line S of any separating surface, the starting point is point A, the end point is point Z, the axis of the rotating shaft is taken as the pole O, and the point passes through

Of rays of

A polar coordinate system is established as a polar axis, and the coordinate system is established in a manner of the condition 1 with the counterclockwise direction as the positive direction.

The present invention points out proposition 1: when points on any separation surface intersecting line S meet the condition that the polar diameter r (theta) (0-theta-AOZ) is a monotone non-decreasing function, the separation surface generated by the axial separation surface S and the sawtooth intersecting line 5 can ensure that the outer wing does not interfere when rotating clockwise around the rotating shaft 3.

And (3) sufficiency proving: take any point P (theta) on the curve S₂,r(θ₂) And the curve S is at any point Q (theta) in the AP section₁,(θ₁))，θ₁≤θ₂Since r (θ) is a monotone non-decreasing function, r (θ)₁)≤r(θ₂) If the point P rotates clockwise around the point O, the point P will not fall on the left side of the curve S, and because the curve S is the boundary between the inner wing and the outer wing, the left side is the inner wing, and the right side is the outer wing, the outer wing follows the point O around the point PThe hour hand can not touch the inner wing when rotating, and interference does not occur.

The necessity proves that: taking any two points P (theta) on the curve S₂,r(θ₂))、Q(θ₁,(θ₁) And satisfies theta₁≤θ₂The point Q is known to lie on the AP segment of the curve S. Because the outer wing does not interfere with the inner wing when rotating clockwise around the point O, the point on the boundary of the outer wing cannot fall on the right side of the boundary of the inner wing when rotating clockwise, and because the inner wing and the outer wing have a common boundary line S, the point P cannot fall on the left side of the AP section of the curve S when rotating clockwise around the point O, and then r (theta)₂)≥r(θ₁) Due to theta₁≤θ₂Then r (θ) is a monotonically non-decreasing function on the curve S.

Fourth, theorems and deductions relating to the intersection line 4 of the axial separating surfaces

The proposition is established after the necessity is fully confirmed. Further the following can be written:

theorem 1: in the coordinate system of the condition 1, a set { S } of the whole curve S in which r (theta) is a monotone non-decreasing function and a set { F } of the separating surfaces generated by the zigzag intersection line 5 constitute a set { F } of the separating surface configuration in which the whole is rotationally noninterference_nonitf}. This theorem 1 is called the folded wing separation plane axial separation theorem.

As shown in FIG. 3, in the coordinate system of the condition 1, the intersection S is formed by two curves S₁、S₂Are formed by splicing and S₁、S₂∈{F_nonitfThe point of intersection of the two curves is point K, the straight line

Radial dimension perpendicular to K point

Then, the following reasoning is made.

Inference 1: for a curve consisting of two curves S₁、S₂∈{F_nonitfH, a curve S formed by splicing, and when S is adopted₂Normal of pole diameter falling at intersection point K of two curves

On the right, the curve S can also form a rotationally noninterference separating surface with the intersection line 5, i.e. S is formed by { F ∈ [)_nonitf}。

Demonstration of inference 1: in the coordinate system of the condition 1, the coordinate of the point K is set to be (theta)₀,r(θ₀) At S)₁、S₂Above each arbitrary point Q (theta)₁,(θ₁))、P(θ₂,r(θ₂) And theta₁≤θ₀≤θ₂. Because of S₁、S₂∈{F_nonitfR (θ) is known from theorem 1₁)≤r(θ₀)、

r(θ₀)≤r(θ₂) Then, there is r (theta)₁)≤r(θ₂) That is, each point on the curve S satisfies the condition that r (theta) is a monotone decreasing function, then the theorem 1 shows that S is equal to F_nonitfAnd finishing the syndrome.

Inference 1 proposes a boundary condition of a splicing design parting surface intersection line, which can be used for autonomously designing the parting surface intersection line, and further generating various parting surface configurations. Inference 1 can also derive another inference.

Inference 2: when the intersection line S is composed of two curves S₁、S₂Are formed by splicing and S₁∈{F_nonitfBut S₂Whether it belongs to { F_nonitfIs unknown if S₂A normal line of a polar diameter which is a straight line segment and falls at the intersection point K of the two curves

On the top or right side, there is also Sec { F_nonitf}. This reasoning is easy to prove and is therefore omitted.

Based on theorem 1, the invention provides a design case of an intersecting line (denoted as type I) of arc-shaped separating surfaces, as shown in fig. 4, three arcs all use a point 6 as a pole O, and have different radiuses.

Based on the inference 2, the invention proposes a design case of intersecting line (denoted as type II) of linear separation surface, as shown in FIG. 5, curve S, i.e. the radius of pole of point A where linear segment AZ falls

On the normal line of (1).

Based on the inference 2, the present invention proposes three design cases of intersecting lines of broken line type separating surfaces (denoted as type III), as shown in FIGS. 5, 6, and 7.

Based on the inference 2, the invention proposes a design case of intersecting line (denoted as type iv) of circular arc and broken line mixed type separating surface, as shown in fig. 8, 10, 11 and 12.

Based on the inference 2, the present invention proposes a design case of the intersection line (denoted as v-shape) of the circular arc and the straight line hybrid separation surface, as shown in fig. 9.

Based on the principle, the invention relates to a method for designing the separating surface of the folding wing without changing the aerodynamic shape, which comprises the following steps:

the method is characterized in that:

The method is characterized in that: for any axial separating surface intersecting line S, the starting point of the intersecting line S is point A, the end point is point Z, the rotating shaft is used as the pole O, and the point passes through

Of rays of

the intersecting line S of the axial separating surfaces comprises a type I, the three circular arcs use a point 6 as a pole O, and the radii of the three circular arcs are different.

Example one

The invention provides a first design example of a separating surface, as shown in figure 17, an inner wing and an outer wing are coupled together in a zigzag structure with staggered canines, the outer wing 2 rotates around a rotating shaft 3, the top view is shown in figure 1, an intersection line 5 adopts a zigzag design, and an intersection line 4 of axial separating surfaces with different sawtooth cross sections adopts a mixed overlapping of a type I and a type IV.

The IV-type separating surface axial separating surface intersecting line 4 provided by the invention can generate a series of structural appearances with baffles with a sawtooth intersecting line 5, as shown in fig. 18, the baffles 21 are limiting plates of inner wings, the grooves 22 are limiting grooves of outer wings, the meshing of the

baffles

21 and 22 limits the outer wings to rotate continuously around the anticlockwise direction after being flattened, the outer wings have a tendency of rotating upwards under the action of aerodynamic force when the folding wing aircraft flies, and the

structures

21 and 22 limit the rotation and can be used as a bearing structure to balance the aerodynamic load of the outer wings, so that the bearing force of a folding wing locking mechanism is greatly reduced, and the design of the locking mechanism can be greatly simplified.

The invention improves the first embodiment, and the intersecting line 4 of the axial separating surfaces of the IV-type and II-type mixed separating surfaces and the intersecting line 5 with fewer saw teeth are adopted, so that the separating surfaces are generated. As shown in fig. 19, the transverse projections of the two front sawteeth are straight lines, and the separating surfaces are planes, so that the circular arc surface of the first example is replaced, and the defect of overlarge error caused by difficult positioning of the circular arc surface can be reduced. The intersecting line of the cross sections of the three rear sawtooth structures is IV-shaped, as shown in fig. 20, the three pairs of limiting plates are meshed with the limiting grooves and are jointly used as a force bearing structure to balance the pneumatic load on the outer wing, and the reliability is higher than that of the first embodiment.

The design of the inner wing and the outer wing is that the inner wing and the outer wing are cut out by using the separating surfaces on the basis of a complete wing type, and the inner wing and the outer wing are in a flat state to form the complete wing type appearance, namely the aerodynamic appearance is not changed. Under the premise, a design method of the separating surface is provided, namely, an intersecting line 4 and an intersecting line 5 of the axial separating surface which do not interfere with rotation are designed, namely, theorems 1,

deductions

1 and 2 are satisfied, and the intersecting line 4 of the I, II, III, IV and V-shaped axial separating surfaces deduced on the basis of the theorems and the intersecting line 5 of the sawtooth-shaped intersecting line are formed to form the separating surface, so that the outer wing does not interfere with the outer wing when rotating clockwise around the rotating shaft.

The IV-type separating surface intersecting line also induces a limit structure for balancing the aerodynamic load of the outer wing, and is beneficial to structural design.

The inner wing separating surface and the outer wing separating surface are completely occluded without gaps, so that airflow below the wings cannot be left from the gaps to the upper side, and the defect that aerodynamic loss is serious due to the fact that a large number of gaps are left when a conventional design is hollowed is overcome.

The above description is not meant to be limiting, it being noted that: it will be apparent to those skilled in the art that various changes, modifications, additions and substitutions can be made without departing from the true scope of the invention, and these improvements and modifications should also be construed as within the scope of the invention.

Claims

1. A method for designing a separating surface of a folding wing without changing aerodynamic configuration comprises the following steps:

splicing the transverse and longitudinal sub-separation surfaces of the inner wing and the outer wing to obtain a complete separation surface configuration;

the method is characterized in that:

2. The method for designing a separation plane of a folding wing without changing the aerodynamic shape as claimed in claim 1, wherein: for any axial separating surface intersecting line S, the starting point of the intersecting line S is point A, the end point is point Z, the axis of the rotating shaft is taken as a pole O, and the point passes through

Of rays of

Establishing a polar coordinate system as a polar axis, and taking the anticlockwise direction as the positive direction; the starting point A and the end point Z are respectively positioned on the symmetrical axial sections of the upper and lower surface sawtooth type intersecting lines; when the point above the function satisfies that the polar diameter r (theta) (theta is more than or equal to 0 and less than or equal to AOZ) is a monotone non-decreasing function, the separation surface generated by the intersection line S and the sawtooth-shaped intersection line can ensure that the outer wing does not interfere when rotating clockwise around the rotating shaft.

3. The method for designing a separation plane of a folding wing without changing the aerodynamic shape as claimed in claim 1, wherein: the intersecting line S of the axial separating surfaces comprises a type I, the three circular arcs use a point O as a pole O, and the radii of the three circular arcs are different.

4. The method for designing a separation plane of a folding wing without changing the aerodynamic shape as claimed in claim 1, wherein: the intersecting line S of the axial separating surfaces comprises a type II, and a curve S, namely the polar diameter of a straight line segment AZ falling at a point A

On the normal line of (1).

5. The method for designing a separation plane of a folding wing without changing the aerodynamic shape as claimed in claim 1, wherein: the axial separating surface intersecting line S comprises a type III: three fold line type separating surface intersecting lines.

6. The method for designing a separation plane of a folding wing without changing the aerodynamic shape as claimed in claim 1, wherein: the axial separating surface intersecting line S comprises a type IV: the intersection line of the circular arc and the linear mixed type separating surface.