Large wind turbine blade with bionic fish scale structure

Abstract

The large wind turbine blade with the bionic fish scale structure comprises a blade front edge, a blade rear edge and a blade body, a bionic fish scale surface is arranged on the side face of the tip end of the blade body, and a plurality of bionic fish scale unit structures arranged according to a preset rule are arranged on the bionic fish scale surface. And the contact surface of the tip side face of the blade body and airflow forms a bionic non-smooth surface. Flow control based on the surface bionic fish scale structure is adopted, the flow characteristic of fluid on the surface of the blade is improved, the surface pressure difference of the blade is increased, and the aerodynamic performance of the blade of the large wind turbine is improved. As the surface pressure difference of the blades is increased, the adaptability of the wind turbine under the conditions of different wind speeds and wind directions is improved. This means that the wind turbine can stably operate under a wider range of environmental conditions, including areas where the wind speed changes greatly or the wind direction is unstable.

Description

Technical Field

[0001] The invention relates to the field of wind turbines, and in particular to a large wind turbine blade with a bionic fish scale structure. Background Art

[0002] A wind turbine is a device that converts wind energy into electrical energy. Its basic principle is to use wind power to drive the wind wheel to rotate, capture wind energy through the blades on the wind wheel, and then drive the rotor inside the generator to rotate, generating electromagnetic induction, thereby generating current. A wind turbine is mainly composed of a wind wheel, a generator, a tower, and a control system. The wind wheel is a key component for capturing wind energy. It is usually composed of multiple blades. These blades rotate under the action of wind power and convert the kinetic energy of the wind into mechanical energy; the generator converts mechanical energy into electrical energy and supplies it to the power grid or directly used in electrical equipment. It is a clean and renewable energy technology that is of great significance to reducing greenhouse gas emissions and achieving sustainable energy development.

[0003] At present, research has made progress in airfoil optimization and small wind turbine blade design, such as bionic airfoil design and the application of vortex generators. Under certain conditions, it can significantly improve the aerodynamic performance and power generation efficiency of the blade. Although research has made progress in airfoil optimization and small wind turbine blade design, there is still room for in-depth exploration in the bionic design of large wind turbine blades. Summary of the invention

[0004] This study aims to fill the gap in existing research and focuses on the design of bionic blades for large wind turbines. The bionic fish scale blade design can optimize the aerodynamic performance of the blade by imitating the scale structure of fish in nature. Studies have shown that this design can effectively improve the lift-to-drag ratio and wind energy utilization.

[0005] To achieve the above objectives, the present invention provides a large wind turbine blade with a bionic fish scale structure, which includes: a blade leading edge, a blade trailing edge, and a blade body. The tip side of the blade body is provided with a bionic fish scale surface, and the bionic fish scale surface is provided with a plurality of bionic fish scale unit structures arranged according to a predetermined rule, so that the contact surface between the tip side of the blade body and the airflow forms a bionic non-smooth surface.

[0006] A further improvement of the present invention is that it is applied to a three-blade wind turbine.

[0007] A further improvement of the present invention is that the bionic fish scale unit structure includes an upper surface, a lower surface, and three side surfaces; the upper surface is an inclined surface, the lower surface is the impeller blade surface, and the intersection of the upper and lower surfaces is the vertex of the bionic fish scale unit; the height H of the trailing edges of the upper and lower surfaces of the bionic fish scale unit is 4 to 6 mm.

[0008] A further improvement of the present invention is that the upper surface and the lower surface of the bionic fish scale unit structure are projected on a plane in a fan-like shape, including a circular arc and two line segments; the front width of the fan-shaped fish scale is W f =0.048m, side width W b =0.08m, height H f =0.12m.

[0009] A further improvement of the present invention is that the arrangement of the fish scale unit structures on the bionic fish scale surface of the blade main body surface is as follows: the bionic fish scale unit structures are arranged in parallel, the lateral spacing a of the bionic fish scale unit structures is 0.24m, and the longitudinal spacing b is 0.08m; the distance c between the rightmost bionic fish scale unit structure and 21% of the chord length of the blade tip is 0.7m; in the bionic fish scale unit structure, the number of bionic fish scale unit structures in each lateral row is 8, and the number of bionic fish scale unit structures in each longitudinal column is 11.

[0010] The advantages of the present invention are as follows:

[0011] (1) The present invention adopts flow control based on the surface bionic fish scale structure to improve the fluid flow characteristics on the blade surface, increase the surface pressure difference of the blade, and enhance the aerodynamic performance of large wind turbine blades.

[0012] (2) Due to the increase in the pressure difference on the blade surface, the adaptability of the wind turbine to different wind speed and wind direction conditions has been improved. This means that the wind turbine can operate stably under a wider range of environmental conditions, including in areas with large changes in wind speed or unstable wind direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram of a blade according to an embodiment of the present invention;

[0014] Figure 2 A schematic diagram of the arrangement of a bionic fish scale unit structure according to an embodiment of the present invention;

[0015] Figure 3 A schematic diagram of a plan projection of a fish scale unit structure according to an embodiment of the present invention;

[0016] Figure 4 This is a schematic diagram of the sizes of multiple fish scale units according to an embodiment of the present invention;

[0017] Figure 5 A schematic diagram of a calculation domain according to an embodiment of the present invention;

[0018] Figure 6 A comparison diagram of blade output torque under rated working conditions provided by an embodiment of the present invention;

[0019] Figure 7It is a comparison diagram of the output torque of wind turbine blades under non-rated working conditions;

[0020] Figure 8 A comparison diagram of blade lift coefficients under rated conditions provided by an embodiment of the present invention;

[0021] Fig. 9 A comparison diagram of blade lift coefficients under non-rated conditions provided by an embodiment of the present invention;

[0022] Wherein, the accompanying drawings are marked as follows:

[0023] 1. Leading edge of blade; 2. Trailing edge of blade; 3. Surface of one side of blade; 4. Surface of the other side of blade; 5. Bionic fish scale structure; 501. Bionic fish scale unit structure; 502. Front side of bionic fish scale structure; 503. Right side of bionic fish scale structure; 504. Left side of bionic fish scale structure. DETAILED DESCRIPTION

[0024] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0025] While some exemplary embodiments of the present invention have been described for the purpose of illustration, it should be understood that the present invention may be implemented in other ways not specifically shown in the drawings.

[0026] According to the attached figure Figures 1 to 4 , give the preferred embodiments of the present invention, and describe them in detail so that the functions and features of the present invention can be better understood.

[0027] like Figure 1 As shown, a large wind turbine blade with a bionic fish scale structure according to an embodiment of the present invention specifically includes: the bionic fish scale blade comprises a blade leading edge 1, a blade trailing edge 2, and a blade body. The two side surfaces 3 of the blade body and the blade surface 4. A portion of the tip of the blade surface 3 is a bionic fish scale surface, and the surface is provided with a bionic fish scale structure 5 arranged in a certain pattern, and the bionic fish scale structure on the blade surface is arranged in parallel.

[0028] In one embodiment of the present invention, Figure 2 As shown, the bionic fish scale structure consists of a bionic fish scale structure upper surface 501, a bionic fish scale structure lower surface, and three bionic fish scale structure side surfaces 502, 503, and 504. The bionic fish scale structure lower surface is the impeller blade surface.

[0029] In one embodiment of the present invention, Figure 3 As shown, the geometric parameters of a single fan-shaped fish scale include the front width W of the fish scale f =0.048m, side width W b =0.08m, height H f =0.12m. Figure 4 As shown, the lateral spacing of the fan-shaped fish scales is a, and the longitudinal spacing is b = 0.08m.

[0030] In order to accurately and comprehensively test the influence of fish scale bionic blades on the aerodynamic characteristics of large wind turbines, the present invention uses computational fluid dynamics (CFD) software to perform numerical simulation analysis on fish scale blades. Figure 5 As shown. The flow field outside the computational domain is cylindrical, with a length of 6D and a cylindrical ground radius of 1.5D. The internal rotating area is encrypted. The rotating area is located 1D away from the opening end and 5D away from the outlet end. Its shape is a radius of 116m and a thickness of 40m. Fluent meshing uses unstructured mesh technology to process the computational domain, the rotating domain, and the fish scale local encrypted area. Figure 5 As shown, the wind speed is introduced through the velocity inlet, passes through the computational domain, and passes through the pressure outlet.

[0031] In this embodiment, a total of 5 different fish scale structure layout schemes are designed, namely pfs-1 (a = 0.19m, b = 0.08m), pfs-2 (a = 0.20m, b = 0.08m), pfs-3 (a = 0.22m, b = 0.08), pfs-4 (a = 0.24m, b = 0.08m), pfs-4 (a = 0.26m, b = 0.08m). Compared with ordinary fan blades, it is found through comparative analysis that pfs-4 (a = 0.24m, b = 0.08m) has better aerodynamic performance, so the fish scale lateral spacing of 0.24m and longitudinal spacing of 0.08m are used as test examples for illustration. The specific method is to set the turbulence intensity in fluent to 1% and the pressure at the outlet to 0Pa. In order to more accurately reproduce the actual operation of the wind turbine, the present invention adopts two working conditions. Rated working conditions: inlet wind speed: 10m / s, rotation speed: 5.864rad / min. Non-rated working conditions: inlet wind speed: 8m / s, rotation speed: 4.351rad / min. Figure 6 The figure shows the output torque comparison of wind turbine blades under rated conditions. Figure 6 It can be seen that the output torque of the fish scale blade is increased by 3.87% compared with the ordinary blade. Figure 7 The figure shows the output torque comparison of wind turbine blades under non-rated working conditions. Figure 7 It can be seen that the output torque of the fish scale blade is increased by 3.45% compared with the ordinary blade. Figure 8The figure shows the lift coefficient comparison of wind turbine blades under rated conditions. Figure 8 It can be seen that the lift coefficient of the fish scale blade is increased by 2.91% compared with the ordinary blade. Fig. 9 The figure shows the lift coefficient comparison of wind turbine blades under non-rated conditions. Fig. 9 It can be seen that the lift coefficient of the fish scale blade is increased by 4.9% compared with the ordinary blade. It can be seen that the fish scale bionic blade can effectively improve the aerodynamic performance of the wind turbine blade and provide a new solution for improving the wind energy utilization efficiency of the wind turbine. By analyzing the pressure distribution of the wind turbine blade, the pressure difference of the ordinary blade is 5663.19Pa, and the pressure difference of the fish scale bionic blade is 5821.6Pa. The surface pressure of the fish scale bionic blade is higher than that of the ordinary blade. At the same time, it also proves that the above-mentioned fish scale blade has a large lift.

[0032] The technical problem to be solved by the present invention is to provide a large wind turbine blade with a bionic fish scale structure, and realize flow control based on the parallel arrangement structure of the surface bionic fish scales. To achieve the above purpose, the technical scheme of the present invention is: a large wind turbine blade with a bionic fish scale structure, the bionic blade comprises a blade leading edge, a blade trailing edge, and a blade body, a section of the blade tip on one side of the blade body is a bionic fish scale structure, and the bionic fish scale surface is provided with a bionic fish scale structure arranged according to a certain rule, so that the blade body and the fluid contact surface form a bionic non-smooth surface. Further, the number of the bionic impeller blades is 3, and the bionic fish scale structure is composed of an upper surface, a lower surface, and three side surfaces. The upper surface is an inclined surface, and the lower surface is the impeller blade surface. The intersection of the upper and lower surfaces is the vertex of the bionic fish scale unit. The height of the trailing edge of the upper and lower surfaces of the bionic fish scale unit is H=4~6mm. Furthermore, the upper and lower surfaces of the bionic fish scale structure are projected on the plane in an approximately fan-shaped shape, consisting of a circular arc and two line segments. The front width of the fan-shaped fish scale is W f =0.048m, side width W b =0.08m, height H f =0.12m.

[0033] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A large wind turbine blade with a bionic fish scale structure, characterized in that: include: The leading edge of the blade, the trailing edge of the blade, the blade body, and the tip side of the blade body are provided with a bionic fish scale surface, and the bionic fish scale surface is provided with a plurality of bionic fish scale unit structures arranged according to a predetermined pattern, so that the contact surface between the tip side of the blade body and the airflow forms a bionic non-smooth surface.

2. A large wind turbine blade with a bionic fish scale structure according to claim 1, characterized in that: Applicable to three-blade wind turbines.

3. The large wind turbine blade with a bionic fish scale structure according to claim 1, characterized in that: The bionic fish scale unit structure includes an upper surface, a lower surface, and three side surfaces; the upper surface is an inclined surface, the lower surface is the impeller blade surface, and the intersection of the upper and lower surfaces is the vertex of the bionic fish scale unit; the height H of the trailing edges of the upper and lower surfaces of the bionic fish scale unit is 4 to 6 mm.

4. The large wind turbine blade with a bionic fish scale structure according to claim 3, characterized in that: The upper surface and the lower surface of the bionic fish scale unit structure are projected on the plane in a fan-shaped shape, including a circular arc and two line segments; the front width of the fan-shaped fish scale is W f =0.048m, side width W b =0.08m, height H f =0.12m.

5. The large wind turbine blade with a bionic fish scale structure according to claim 4, characterized in that: The arrangement of the fish scale unit structures on the bionic fish scale surface of the blade main body surface is as follows: the bionic fish scale unit structures are arranged in parallel, the lateral spacing a of the bionic fish scale unit structures is 0.24m, and the longitudinal spacing b is 0.08m; the distance c between the rightmost bionic fish scale unit structure and 21% of the chord length of the blade tip is 0.7m; in the bionic fish scale unit structure, the number of bionic fish scale unit structures in each lateral row is 8, and the number of bionic fish scale unit structures in each longitudinal column is 11.

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