Double-element wing sail with main wing leading edge of non-uniform protruding structure

Abstract

The double-element wing sail is characterized in that a ship body and a mast are included, the mast is fixedly installed on the ship body, the main wings and flaps are arranged on the mast, the main wings and the flaps are fixedly installed on the mast, the main wings and the flaps are installed in the mast in a large-small state, and the main wings and the flaps are arranged in a large-small state. The front edge of the main wing is of a protruding structure to change flowing on the airfoil surface, and the effect of improving the lift force at the initial stage of stall is achieved. The main wing of the double-element wing sail is subjected to bionic modification design by referring to a front edge bulge structure of a fin-shaped limb of a seat head whale, and a non-uniform bulge improvement scheme of the front edge of the main wing of the double-element wing sail is provided, so that the lifting amplitude at the initial stage of stall is improved, the load stability of the wing sail is ensured, and the application scene is expanded; the action effect is proved through flow field simulation.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy for ships, and in particular to a dual-element wing sail with a non-uniform convex configuration at the leading edge of the main wing. Background Art

[0002] Within most wind angles (0° - 120°) during ship navigation, the installation angle of attack of the wing sail is less than the stall angle to ensure that the maximum ship propulsion force can be obtained by making full use of the lift coefficient of the wing sail. However, according to the lift-drag characteristic curve of the wing sail, the angle of attack corresponding to the maximum lift coefficient before stall is adjacent to the stall angle. The angle-of-attack fluctuations caused during ship navigation and the interference of the upstream wing sail on the flow field of the downstream wing sail are likely to cause the wing sail to stall, threatening the safety of the wing sail and the ship. Conducting research on the stall control method of the wing sail has become a topic of concern for scholars at home and abroad. Currently, the methods for controlling airfoil stall are mainly divided into two categories: passive control and active control, mainly based on passive control methods and active control methods. The passive control method is also called wing modification, which improves stall by adjusting the geometric structure of the wing airfoil or blade, and this does not require external energy. Active control is to locally control the flow field around the wing airfoil or blade to achieve delayed or accelerated transition, delay flow separation, and achieve the effect of delaying stall. In order to improve the stall characteristics of the sail, currently applied technologies include active control technologies such as blowing, turbine suction, plasma excitation, and controllable circulation wings, and passive control technologies such as setting leading-edge slats, variable flaps, and leading-edge convex modifications. The improvement of the lift reduction at the initial stage of stall in the prior art cannot ensure the stable load of the wing sail, and the single use scenario cannot meet different flap deflection angles.

[0003] Therefore, it is necessary to provide a dual-element wing sail with a non-uniform convex configuration at the leading edge of the main wing to solve the above technical problems. By referring to the leading-edge convex structure of the humpback whale flipper, a bionic modification design of the main wing of the dual-element wing sail is carried out, and an improvement scheme for the non-uniform convexity at the leading edge of the main wing of the dual-element wing sail is proposed, including the design of the wavelength and amplitude of the uniform convexity, and the non-uniform convex configuration design aims to improve the stall characteristics of the dual-element wing sail. Summary of the Invention

[0004] The purpose of this part is to outline some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this part, the abstract of the specification, and the title of the invention to avoid obscuring the purpose of this part, the abstract of the specification, and the title of the invention, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] Therefore, the technical problem to be solved by the present invention is the problem of designing the convex wavelength and amplitude of the non-uniform convexity at the leading edge of the main wing, and the non-uniform convex configuration design aims to improve the stall characteristics of the dual-element wing sail.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: A dual-element wing sail with a non-uniform convex configuration at the leading edge of the main wing, characterized in that: a hull and a mast, the mast is fixedly installed on the hull, a main wing and a flap are arranged on the mast, the main wing and the flap are both fixedly installed on the mast, the main wing and the flap are arranged in a large-small state in the mast, and the leading edge of the main wing is a convex structure to change the flow on the wing surface, so as to improve the lift at the initial stage of stall.

[0007] As a preferred scheme of the dual-element wing sail with a non-uniform convex configuration at the leading edge of the main wing of the present invention, the mast is arranged to be rotatable and vertically connected to the hull.

[0008] As a preferred scheme of the dual-element wing sail with a non-uniform convex configuration at the leading edge of the main wing of the present invention, the airfoil of the main wing is NACA0018, and the airfoil of the flap is NACA0015; the volume of the main wing is larger than that of the flap.

[0009] As a preferred scheme of the dual-element wing sail with a non-uniform convex configuration at the leading edge of the main wing of the present invention, the leading edge of the main wing is a convex structure with different sizes

[0010] As a preferred scheme of the dual-element wing sail with a non-uniform convex configuration at the leading edge of the main wing of the present invention, the geometric parameters of the airfoil are respectively defined as follows: the total chord length of the airfoil, the airfoil thickness, the gap width, the flap rotation axis, the flap deflection angle and the angle of attack.

[0011] As a preferred scheme of the dual-element wing sail with a non-uniform convex configuration at the leading edge of the main wing of the present invention, since the projection of the convex leading edge of the main wing in the x-z plane is an approximate sine curve, and its shape depends on the stacking method of the blade in the radial direction, a cubic B-spline curve is taken as the form of the leading edge curve for modeling;

[0012] The B-spline curve refers to the whole curve segment that only relates to n + 1 vertices among m + n + 1 control vertices P i (i = 0, 1, 2,..., m + n), and the k-th n-th order B-spline curve segment (k = 0, 1,..., m) can be represented by Equation 1;

[0013]

[0014] In the formula, G i,n (x) can be defined by Equation 2:

[0015]

[0016] x ∈ [0, 1], i = 1, 2...n

[0017] Among them, the cubic B-spline curve can be represented by Equation 3:

[0018]

[0019]

[0020] Taking n = 3 as an example, the spline curve of the k-th segment (k = 0, 1, …, m) can be expressed by Equation 4:

[0021]

[0022] Among them, a single wavelength is only related to 4 control points. Taking them as the profile points for cubic B-spline interpolation fitting, a cubic B-spline fitting curve with second-order geometric continuity can be obtained. Furthermore, the geometric configuration of the leading-edge bulge can be completed by interpolation fitting in combination with the basic airfoil;

[0023] Taking the leading-edge bulge constructed with the NACA0018 airfoil as an example, the amplitude is taken as 0.14c, the spanwise wavelength is taken as 0.28c, and the maximum wave amplitude is 0.24c.

[0024] As a preferred scheme of the two-element wing sail with the non-uniform bulge configuration at the leading edge of the main wing according to the present invention, it also includes the stall characteristics of different modification schemes of the leading-edge bulge of the main wing, and the stall characteristics include the stall angle, the maximum lift coefficient, and the lift reduction at the initial stage of stall.

[0025] As a preferred scheme of the two-element wing sail with the non-uniform bulge configuration at the leading edge of the main wing according to the present invention, it also includes increasing the maximum wave amplitude of the bulge in the middle of the main wing while also increasing its wavelength to match its aerodynamic performance.

[0026] As a preferred scheme of the two-element wing sail with the non-uniform bulge configuration at the leading edge of the main wing according to the present invention, the total chord length of the airfoil is 3.5 m.

[0027] The beneficial effects of the present invention: The present invention draws on the leading-edge bulge structure of the humpback whale flipper, makes a bionic modification design for the main wing of the two-element wing sail, and proposes an improved scheme for the non-uniform bulge at the leading edge of the main wing of the two-element wing sail, including the design of the wavelength and wave amplitude of the uniform bulge, and the non-uniform bulge configuration design aims to improve the stall characteristics of the two-element wing sail; the present invention improves the lift reduction at the initial stage of stall and ensures the stability of the wing sail load; the present invention can be applied to different flap deflection angles; the present invention has verified the action effect through flow field simulation. Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0029] Wherein:

[0030] Figure 1 is a schematic structural diagram of a dual - element wing sail with a non - uniform convex configuration at the leading edge of the main wing provided by the present invention;

[0031] Figure 2 is a schematic diagram of the key geometric parameters of the leading - edge convex configuration of the NACA0018 airfoil of a dual - element wing sail with a non - uniform convex configuration at the leading edge of the main wing provided by the present invention;

[0032] Figure 3 is a force - analysis diagram of the wing sail of a dual - element wing sail with a non - uniform convex configuration at the leading edge of the main wing provided by the present invention when the ship is under stress;

[0033] Figure 4 is a sine - curve graph of a dual - element wing sail with a non - uniform convex configuration at the leading edge of the main wing provided by the present invention;

[0034] Figure 5 is a schematic diagram of the modification scheme of the leading - edge convexity of the main wing of a dual - element wing sail with a non - uniform convex configuration at the leading edge of the main wing provided by the present invention;

[0035] Figure 6 is a distribution diagram of {ρv 2} on the near - wall surface of the suction surface of Case2 of a dual - element wing sail with a non - uniform convex configuration at the leading edge of the main wing provided by the present invention. Detailed Embodiments

[0036] To make the above - mentioned objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be given in conjunction with the accompanying drawings of the specification.

[0037] In the following description, many specific details are set forth to facilitate a thorough understanding of the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0038] Secondly, the present invention will be described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross - sectional views showing the device structure will be enlarged locally out of the general proportion, and the schematic diagrams are only examples and should not limit the scope of protection of the present invention herein. In addition, in actual production, three - dimensional spatial dimensions including length, width, and depth should be included.

[0039] Next, the so-called "one embodiment" or "embodiment" herein refers to specific features, structures, or characteristics that may be included in at least one implementation of the present invention. The phrase "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it an independent or selectively mutually exclusive embodiment with other embodiments.

[0040] Embodiment 1

[0041] Referring to Figures 1-6 , the first embodiment of the present invention provides a dual-element wing sail with a non-uniform convex configuration at the leading edge of the main wing, characterized in that: a hull 101 and a mast 102, the mast 102 is fixedly installed on the hull 101, a main wing 104 and a flap 103 are provided on the mast 102, the main wing 104 and the flap 103 are both fixedly installed on the mast 102, the main wing 104 and the flap 103 are arranged in a large and a small state in the mast 102, the leading edge of the main wing 104 is a convex structure to change the flow on the airfoil surface, playing a role in increasing the lift at the initial stage of stall. Specifically, the hull 101 is made of all-carbon fiber material, which is lightweight. The mast 102 is installed on the surface of the hull 101, a gear is provided at the bottom of the mast 102, and the gear at the bottom of the mast 102 meshes with the inter-pipe linkage unit arranged inside the cabin. The rotation of the gear will drive the mast 102 to rotate. A dual-element wing sail is fixedly installed on the mast 102, and the dual-element wing sail is arranged left and right. Among them, one is the main wing 104 and the other is the flap 103. The volume of the main wing 104 is larger than that of the flap 103. The flap 103 has the same shape on the upper, lower, left, and right surfaces. The main wing 104 has an irregular shape. Non-uniform protrusions are provided at the leading edge of the main wing 104. The gas flow on the airfoil surface is changed through the non-uniform convex configuration at the leading edge of the main wing 104. The main wing 104 and the flap 103 can both rotate. When the wind blows towards the main wing 104, the rotation of the main wing 104 will form an angle of attack. At this time, the flap 103 will be adjusted according to the rotation of the main wing 104, and at the same time, the flap 103 will form a flap deflection angle. The airfoil adopted by the main wing 104 is NACA0018, and the airfoil adopted by the flap 103 is NACA0015. In order to study the convex configuration at the leading edge of the main wing of the dual-element wing sail, it is necessary to design the wavelength and amplitude of the protrusion at the leading edge of the NACA0018 airfoil, and determine the appropriate convex structure at the leading edge of the main wing 104 through aerodynamic characteristic analysis. The definitions of the key geometric parameters of the convex configuration at the leading edge of the NACA0018 airfoil are shown in the figure. The amplitude is the vertical distance from the wave crest to the wave trough, denoted by A. The wavelength is the horizontal distance from one wave crest to another wave crest, denoted by W. In the entire airfoil section, the number of convex waves is the ratio of the convex length to the convex wavelength, denoted by N. ( Figure 2 as shown)

[0042] Figure 4As shown in the figure, since the projection of the leading edge bulge of the NACA0018 airfoil in the x-z plane is an approximate sine curve and its shape depends on the stacking method in the radial direction of the blade, a cubic B-spline curve is taken as the form of the leading edge curve for modeling.

[0043] The B-spline curve refers to all the curve segments where, among m + n + 1 control vertices P i (i = 0, 1, 2,..., m + n), the k-th n-th order B-spline curve segment (k = 0, 1,..., m) is only related to n + 1 vertices, and the equation can be expressed by Equation 1.

[0044]

[0045] In the formula, G i,n (x) can be defined by Equation 2:

[0046]

[0047] x ∈ [0, 1], i = 1, 2... n

[0048] Among them, the cubic B-spline curve can be expressed by Equation 3:

[0049]

[0050]

[0051] Taking n = 3 as an example, the spline curve of the k-th segment (k = 0, 1,..., m) can be expressed by Equation 4:

[0052]

[0053] Among them, a single wavelength is only related to 4 control points. Using these as the shape value points for cubic B-spline interpolation fitting, a cubic B-spline fitting curve with second-order geometric continuity can be obtained. Furthermore, the geometric configuration of the leading edge bulge can be completed by interpolation fitting in combination with the basic airfoil.

[0054] Figure 5 As shown in the figure, taking the leading edge bulge constructed with the NACA0018 airfoil as an example, the amplitude is taken as 0.14c, the spanwise wavelength is taken as 0.28c, and the maximum wave amplitude is 0.24c.

[0055] Figure 5 Modified scheme for the leading edge bulge of the main wing

[0056]

[0057] Figure 6 Stall characteristics of different modified schemes for the leading edge bulge of the main wing

[0058]

[0059] Figure 6 As shown, when α = 10°, due to the increase in the amplitude and wavelength of the large bulge in the middle of the Case2 main wing, the width of the high-momentum band downstream of it increases significantly; as the angle of attack increases to 12°, a low-momentum region appears downstream of the trough between the large bulge and the small bulge below, but the high-momentum band downstream of the large bulge above supplements the energy of the boundary layer through momentum transport, weakening the flow separation; when α = 14°, the high-momentum band downstream of the large bulge shifts upward and its width decreases, but its length does not decrease. Its momentum supplements the energy of the boundary layer in the upper low-momentum region, greatly weakening the flow separation above. The upper low-energy region is also suppressed within a very small range. Under its action, the low-momentum region near the wall of the flap also decreases significantly, and the stall phenomenon that appears is delayed. When α = 16°, a relatively large low-momentum region appears near the wall above the large bulge of the Case2 main wing and has extended to the bottom of the bulge at the leading edge of the main wing. The range of the low-momentum region near the wall of the flap also expands, causing the Case2 wing sail to stall; when α = 18°, this low-momentum region occurs below the large bulge.

[0060] Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention. To provide a concise description of the exemplary embodiments, not all features of the actual embodiments may be described (i.e., those features that are not relevant to the currently considered best mode of implementing the present invention or those features that are not relevant to the implementation of the present invention).

[0061] It should be understood that in the development of any actual implementation, such as in any engineering or design project, a large number of specific implementation decisions may be made. Such development efforts may be complex and time-consuming, but for those of ordinary skill in the art who benefit from this disclosure, without excessive experimentation, such development efforts will be a routine task of design, manufacturing, and production.

[0062] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A dual-element wing sail with a non-uniform convex configuration at the leading edge of the main wing, characterized in that: Hull (101), mast (102), the mast (102) is fixedly installed on the hull (101), the mast (102) is provided with a main wing (104) and a flap (103), the main wing (104) and the flap (103) are both fixedly installed on the mast (102), the main wing (104) and the flap (103) are arranged in a state of one large and one small on the mast (102), and the leading edge of the main wing (104) is a convex structure to change the flow on the airfoil surface, playing a role in increasing the lift at the initial stage of stall.

2. The dual-element wing sail with a non-uniform convex configuration at the leading edge of the main wing according to claim 1, wherein: The mast (102) is arranged to be rotatable and vertical and connected to the hull (101).

3. The dual-element wing sail with a non-uniform convex configuration at the leading edge of the main wing according to claim 1, characterized in that: The airfoil of the main wing (104) is NACA0018, and the airfoil of the flap (103) is NACA0015; the volume of the main wing (104) is larger than the volume of the flap (103).

4. The double-element wing sail with a non-uniform convex configuration at the leading edge of the main wing according to claim 1, characterized in that: The leading edge of the main wing (104) is a convex structure with different sizes.

5. The dual-element wing sail with a non-uniform convex configuration at the leading edge of the main wing according to claim 1, wherein: It also includes the following definitions of the geometric parameters of the airfoil: total chord length of the airfoil, airfoil thickness, gap width, flap rotation axis, flap deflection angle, and angle of attack.

6. The double-element wing sail with a non-uniform convex configuration at the leading edge of the main wing according to claim 5, characterized in that: The projection of the leading edge convexity of the main wing (104) in the x-z plane is an approximate sine curve, and its shape depends on the stacking method in the blade radial direction. Therefore, a cubic B-spline curve is taken as the form of the leading edge curve for modeling; The B-spline curve refers to all curve segments in the m + n + 1 control vertices P i where the k-th n-th order B-spline curve segment is only related to n + 1 vertices, and the equation can be expressed by Equation 1; In the formula, G i,n (x) can be defined by Equation 2: x ∈ [0,1], i = 1,2…n (2) Among them, the cubic B-spline curve can be expressed by Equation 3: Taking n = 3 as an example, the spline curve of the k-th segment can be expressed by Equation 4: Among them, a single wavelength is only related to 4 control points. Using them as the shape value points for cubic B-spline interpolation fitting, a cubic B-spline fitting curve with second-order geometric continuity can be obtained, and then the geometric configuration of the leading edge convexity can be completed by interpolation fitting in combination with the basic airfoil; Taking the leading edge convexity constructed with the NACA0018 airfoil as an example, the amplitude is taken as 0.14c, the spanwise wavelength is taken as 0.28c, and the maximum wave amplitude is 0.24c.

7. The double-element wing sail with a non-uniform convex configuration at the leading edge of the main wing according to claim 6, characterized in that: It also includes the stall characteristics of different modification schemes of the leading edge convexity of the main wing (104), and the stall characteristics include stall angle, maximum lift coefficient, and lift reduction at the initial stage of stall.

8. The dual-element wing sail with a non-uniformly convex configuration at the leading edge of the main wing according to claim 6, characterized in that: It also includes increasing the maximum wave amplitude of the convexity in the middle of the main wing while also increasing its wavelength to match its aerodynamic performance.

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