Active anti-icing structure and method for wind driven generator blade

Abstract

The invention discloses an active anti-icing structure and method for a blade of a wind driven generator, and belongs to the technical field of wind power generation. The active anti-icing structure comprises a blade base body, and the blade base body sequentially comprises a tip area, a middle area and a root area in the direction from the blade tip to the blade root; the vortex generators are distributed on the suction surface of the tip area in the length direction of the blade base body; each vortex generator comprises at least two fins erected on the surface of the blade base body, and the distance between the fins in the airflow direction is larger than the distance in the direction opposite to the airflow direction. The invention aims to solve the problem that the blade surface of the existing wind driven generator blade is easy to be iced in a low-temperature and high-humidity environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind power generation, and in particular relates to an active ice protection structure and method for wind turbine blades. Background Art

[0002] As a clean and renewable energy source, wind power generation is playing an increasingly important role in the global energy structure. However, in winter, especially in high mountain wind farms, when the blade base is operating in a low temperature and high humidity environment, the blade surface is easily covered with ice, which will affect the power evaluation of the wind farm and the safe operation of the wind turbine, causing failure of wind turbine measuring instruments, power loss, load imbalance damage of mechanical equipment, safety accidents, etc. The power generation loss caused by wind turbine blade icing is about 1% to 10% each year, and can reach 20% to 50% in serious areas.

[0003] At present, the industry has taken a variety of measures to address the anti-icing problem of the blade base, mainly including active anti-icing and passive anti-icing strategies. Active anti-icing technologies such as electric heating and gas-heat deicing use external energy input to melt the ice layer, but these methods have high energy consumption and require the installation of additional heating units and their control systems on the blades, which are costly and have limited economic benefits. Passive anti-icing technologies such as adding hydrophobic coatings, ice-phobic coatings, black coatings, and freezing point inhibitors to the blade surface can reduce the adhesion between ice and the blade by changing the surface properties of the blade to achieve an anti-icing effect, but these methods cannot completely suppress the formation of ice, but rather slow down ice accumulation. They have limited capabilities in heavy ice areas, are difficult to maintain, and are prone to polluting the environment.

[0004] In summary, the existing anti-icing technology cannot fundamentally solve the blade icing problem, so there is an urgent need for an energy-saving and efficient active anti-icing method in this field. Summary of the invention

[0005] In view of the above problems, the present invention provides an active anti-icing structure and method for wind turbine blades, aiming to solve the problem that the blade surfaces of existing wind turbine blades are easily covered with ice in low temperature and high humidity environments.

[0006] To achieve the above object, the technical solution adopted by the present invention is: an active anti-icing structure for wind turbine blades, comprising:

[0007] A blade base, which includes a tip region, a middle region and a root region in sequence from the blade tip to the blade root of the blade base;

[0008] Vortex generators are distributed on the suction surface of the tip region along the length direction of the blade base;

[0009] Each vortex generator includes at least two fins standing on the surface of the blade base, and the spacing between the fins is greater in the direction toward the airflow than in the direction away from the airflow.

[0010] As a further improvement of the above scheme, the vortex generators are arranged in at least one row along the length direction of the blade base; adjacent vortex generators in the same row are arranged in a stepped manner. The stepped vortex generators can more effectively disturb the airflow and enhance the separation effect of the airflow, thereby generating more high-energy vortices on the blade surface and improving the anti-icing efficiency.

[0011] As a further improvement of the above scheme, the vortex generator includes a bottom plate, on which two fins are vertically arranged at intervals; the fins are arranged in an eight-shaped shape; and the bottom plate is installed on the surface of the blade base. The fins arranged in an eight-shaped shape can better adapt to the direction of the airflow, increase the contact area between the airflow and the blade surface, improve the generation efficiency of the vortex, and enhance the anti-icing effect.

[0012] As a further improvement of the above scheme, the angle between the fins of the vortex generator is 10°-50°; the minimum spacing between the fins is 5-30mm, and the pitch of adjacent vortex generators is 5-30mm. By adjusting the angle and spacing between the fins, the effect of the vortex generator on the airflow can be optimized, so that the vortex is more evenly distributed on the blade surface, improving the anti-icing effect while reducing the resistance to the airflow.

[0013] As a further improvement of the above solution, the length of the tip area is 1 / 3-1 / 2 of the total length of the blade. The adjustment of the length of the tip area allows the vortex generators to be mainly concentrated in the front part of the blade, where ice is most serious, and can more effectively prevent ice formation.

[0014] As a further improvement of the above solution, the fin is triangular or trapezoidal; the side of the fin facing the airflow direction is the windward side; the side facing away from the airflow direction is the leeward side. The triangular or trapezoidal fin design can increase the area of ​​the windward side and improve the efficiency of vortex generation, while the smaller area of ​​the leeward side can reduce the resistance of the airflow to the blade.

[0015] As a further improvement of the above solution, the length of the windward surface is greater than that of the leeward surface. The increase in the length of the windward surface can improve the efficiency of vortex generation, while the shorter leeward surface can reduce the resistance of the airflow to the blade and improve the aerodynamic performance of the blade.

[0016] As a further improvement of the above solution, the windward surface is in an arc shape and / or the leeward surface is in an arc shape. The arc-shaped windward surface and leeward surface can reduce the impact of airflow on the blades, reduce noise, and improve the efficiency of vortex generation.

[0017] As a further improvement of the above solution, the surface of the blade substrate and the surface of the vortex generator are coated with a lightning protection layer and a super hydrophobic coating. The lightning protection layer can protect the blade from damage by lightning strikes, and the super hydrophobic coating can reduce the adhesion of water droplets on the blade surface, further improving the anti-icing effect.

[0018] A method for actively preventing ice from falling on blades of a wind turbine generator adopts the active anti-icing structure for blades of a wind turbine generator, and a vortex generator is installed on the surface of the blade to generate high-energy induced vortices on the surface of the blade, thereby destroying the boundary layer of the fluid surface and making the surface turbulent. In a turbulent environment, the shear force to which the droplets are subjected will be greater than the adhesion force, and the droplets cannot be adsorbed on the surface of the blade to form a water film, thereby achieving the purpose of actively preventing ice from falling on the surface of the blade.

[0019] The beneficial effects of the present invention are:

[0020] 1. The setting of vortex generators enhances the energy of the fluid in the boundary layer, reduces the adhesion of water droplets on the blade surface, and thus reduces the possibility of icing. And it only covers the tip of the blade, which can not only ensure the active anti-icing coverage of the key parts of wind energy conversion, but also take into account the production cost.

[0021] 2. The vortex generator is set to cut the airflow during the rotation of the blade, forming many high-energy vortices on the surface of the blade, promoting the rotation of the blade and improving the aerodynamic performance.

[0022] 3. The present invention has a simple structural design, is easy to install, has a low maintenance cost, does not cause damage to the blades, and has good economy and environmental protection.

[0023] 4. The dual anti-icing structure of the present invention is suitable for blade bases of various models and sizes and has wide applicability.

[0024] In summary, the present invention provides an effective solution for active anti-icing of wind turbine blades, which has important practical value and market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the top structure of the present invention.

[0026] Figure 2 for Figure 1 Schematic diagram of the AA cross-sectional structure.

[0027] Figure 3 This is a top view of the fin distribution of the vortex generator.

[0028] Figure 4 Schematic diagram of the fin structure.

[0029] Figure 5 Schematic diagram of the three-dimensional structure of the vortex generator.

[0030] Explanation of the reference numerals: 1. tip area; 2. middle area; 3. root area; 4. vortex generator; 11. suction surface; 12. pressure surface; 13. leading edge; 14. trailing edge; 100. bottom plate; 200. fin; 210. windward surface; 220. leeward surface; 240. top surface. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solution, the present invention is described in detail below in conjunction with embodiments. The description in this section is only exemplary and explanatory and should not have any limiting effect on the scope of protection of the present invention.

[0032] like Figure 1-5 As shown, as a specific embodiment of the present invention, an active anti-icing structure for a wind turbine blade includes:

[0033] The blade base includes a tip region 1, a middle region 2 and a root region 3 in sequence from the blade tip to the blade root of the blade base;

[0034] The vortex generators 4 are distributed on the suction surface 11 of the tip region 1 along the length direction of the blade base;

[0035] Each vortex generator 4 includes at least two fins 200 standing on the surface of the blade base, and the spacing between the fins 200 is greater in the direction toward the airflow than in the direction away from the airflow.

[0036] Specifically, Figure 1 As shown, the end of the root area 3 is connected to the rotating shaft of the wind turbine; when viewed from the top of the blade base, the blade width gradually increases from the tip area 1 to the middle area 2; and the blade width gradually decreases from the end of the middle area 2 to the root area 3.

[0037] The fins 200 of the vortex generator 4 are generally designed to be streamlined.

[0038] To improve installation efficiency, 3-5 pairs of vortex generators can be installed on a large base plate, which is then installed on the collective surface of the blades.

[0039] like Figure 2 As shown, the cross-sectional shape of the blade base is an airfoil, including a suction surface 11, a pressure surface 12, a leading edge 13 and a trailing edge 14, and the direction from the leading edge 13 to the trailing edge 14 is the length direction.

[0040] like Figure 1 As shown, as a preferred embodiment of the above embodiment, the vortex generators 4 are arranged in at least one row along the length direction of the blade base; adjacent vortex generators 4 in the same row are arranged in a stepped manner.

[0041] The vortex generators 4 in the same row are arranged in a stepped manner, which means that the vortex generators 4 are arranged in a straight line along the length direction of the blade base, and the vortex generators 4 in the same row are arranged one by one in a stepped manner and retreated a certain distance along the flow direction of the wind force, such as Figure 1 shown.

[0042] like Figure 5 As shown, as a preferred embodiment of the above embodiment, the vortex generator 4 includes a bottom plate 100, on which two fins 200 are vertically arranged at intervals; the fins 200 are arranged in an eight-shaped shape; and the bottom plate 100 is installed on the surface of the blade base.

[0043] like Figure 3 As shown, as a preferred embodiment of the above embodiment, the angle β between the fins 200 of the vortex generator 4 is 10°-50°; the minimum spacing S1 of the fins 200 is 5-30 mm, and the pitch S2 of adjacent vortex generators is 5-30 mm.

[0044] like Figure 1 As shown, as a preferred embodiment of the above embodiment, the length of the tip area 1 is 1 / 3-1 / 2 of the total length of the blade.

[0045] like Figure 4-5 As shown, as a preferred embodiment of the above embodiment, the fin 200 is triangular or trapezoidal; the side of the fin 200 facing the airflow direction is the windward side 210; and the side facing away from the airflow direction is the leeward side 220.

[0046] like Figure 1 As shown, as a preferred embodiment of the above embodiment, the length of the windward surface 210 is greater than the length of the leeward surface 220 .

[0047] like Figure 1 As shown, as a preferred embodiment of the above embodiment, the windward surface 210 is in an arc shape and / or the leeward surface 220 is in an arc shape.

[0048] The fin 200 is triangular and may be an acute triangle, an obtuse triangle, a right triangle or a streamlined shape.

[0049] like Figure 4 In the C or D type structure, the fin 200 is a right triangle, the long side of the right angle is set to be connected with the bottom surface and the surface of the blade base, and the hypotenuse of the right angle triangle is used as the windward surface to face the airflow direction during the rotation of the blade; or the hypotenuse of the triangle is set to be connected with the bottom surface and the surface of the blade base, and the long side of the right angle is used as the windward surface to face the airflow direction during the rotation of the blade.

[0050] like Figure 4In the middle F-shaped structure, the fin 200 is an obtuse triangle, the second long side of the obtuse angle is set to be connected to the bottom surface of the blade surface, and the first long side of the obtuse angle is used as the windward side facing the airflow direction during the rotation of the blade.

[0051] like Figure 4 In the middle E-shaped structure, the fin 200 is an acute triangle, the first long side of the acute angle is set as the bottom surface connected to the blade surface, and the second long side of the acute angle is used as the windward side facing the airflow direction during the rotation of the blade.

[0052] like Figure 4 In the middle G-type structure, the leeward side of the fin can be a convex arc shape, such as Figure 4 In the I-type structure, the leeward side of the fin can be a concave arc shape, such as Figure 4 In the H-shaped structure, the windward surface of the fin can be a convex arc shape.

[0053] Figure 4 The C, D, E, and F structures in the figure can be transformed into a trapezoidal fin 200 structure by cutting off the top corners along the dotted line position in the figure, that is, Figure 5 The top surface 240 of the trapezoid in the embodiment.

[0054] As a preferred embodiment of the above embodiment, the surface of the blade substrate and the surface of the vortex generator 4 are coated with a lightning protection layer and a super-hydrophobic coating.

[0055] An active anti-icing method for wind turbine blades adopts an active anti-icing structure for wind turbine blades, and a vortex generator 4 is installed on the blade surface to generate high-energy induced vortices on the blade surface, thereby destroying the boundary layer of the fluid surface and making the surface turbulent. In a turbulent environment, the shear force on the droplets will be greater than the adhesion force, and the droplets cannot be adsorbed on the blade surface to form a water film, thereby achieving the purpose of active anti-icing on the blade surface.

[0056] The anti-icing principle of this method is:

[0057] Ice coating on the blade substrate is a process in which supercooled water droplets first accumulate on the blade surface, followed by ice crystal nucleation and growth. The accumulation of droplets on the blade surface requires the droplets to hit the blade surface, vibrate the droplet surface, and stay. In this process, the droplets are affected by adhesion force, shear force, etc. When the adhesion force is less than the shear force, the droplets cannot be adsorbed on the blade surface to form a water film, and there is no subsequent ice crystal nucleation and growth process.

[0058] Installing vortex generators on the blade surface can generate high-energy induced vortices on the blade surface, destroying the boundary layer of the fluid surface and making the surface turbulent. In this turbulent environment, the shear force on the droplets will be greater than the adhesion force, and they will not be able to adsorb to the blade surface to form a water film, thus achieving the purpose of active anti-icing on the blade surface.

[0059] The vortex generator can not only increase the power generation, but also reduce the blade load, indirectly improving the structural strength of the blade. The vortex generator removes water through the vortex created by the wind itself, without the need for additional energy from the outside, and without the introduction of other substances to affect the environment, which is energy-saving and environmentally friendly.

[0060] It should be noted that, in this article, the terms: include, contain and any other variants are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. Specific examples are used in this article to illustrate the principle and implementation of the technical solution of the present invention. The above examples are only used to help understand the method of the present invention and its core idea. The above are only preferred implementations of the present invention. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements, modifications or changes can be made, and the above technical features can also be combined in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the concept and technical solution of the present invention to other occasions without improvement, should be regarded as the protection scope of the present invention.

Claims

1. An active anti-icing structure for wind turbine blades, characterized in that: include: A blade base, which includes a tip region (1), a middle region (2) and a root region (3) in sequence from the blade tip to the blade root of the blade base; Vortex generators (4) are distributed on the suction surface (11) of the tip region (1) along the length direction of the blade base; Each vortex generator (4) comprises at least two fins (200) standing on the surface of the blade base, and the spacing between the fins (200) is such that the spacing in the direction facing the airflow is greater than the spacing in the direction facing away from the airflow.

2. The active anti-icing structure for wind turbine blades according to claim 1, characterized in that: The vortex generators (4) are arranged in at least one row along the length direction of the blade base; adjacent vortex generators (4) in the same row are arranged in a stepped manner.

3. The active anti-icing structure for wind turbine blades according to claim 1, characterized in that: The vortex generator (4) comprises a bottom plate (100), on which two fins (200) are vertically arranged at intervals; the fins (200) are arranged in an eight-shaped shape; and the bottom plate (100) is mounted on the surface of a blade base.

4. The active anti-icing structure for wind turbine blades according to claim 2, characterized in that: The angle between the fins (200) of the vortex generator (4) is 10°-50°; the minimum spacing between the fins (200) is 5-30 mm, and the pitch between adjacent vortex generators (4) is 5-30 mm.

5. The active anti-icing structure for wind turbine blades according to claim 1, characterized in that: The length of the tip area (1) is 1 / 3-1 / 2 of the total length of the blade.

6. The active anti-icing structure for wind turbine blades according to claim 1, characterized in that: The fin (200) is triangular or trapezoidal; the side of the fin (200) facing the airflow direction is the windward side (210); and the side facing away from the airflow direction is the leeward side (220).

7. The active anti-icing structure for wind turbine blades according to claim 6, characterized in that: The length of the windward surface (210) is greater than the length of the leeward surface (220).

8. The active anti-icing structure for wind turbine blades according to claim 6, characterized in that: The windward surface (210) is in an arc shape and / or the leeward surface (220) is in an arc shape.

9. The active anti-icing structure for wind turbine blades according to claim 1, characterized in that: The surface of the blade substrate and the surface of the vortex generator (4) are coated with a lightning protection layer and a super-hydrophobic coating.

10. An active anti-icing method for wind turbine blades, using the active anti-icing structure for wind turbine blades according to any one of claims 1 to 9, characterized in that: By installing a vortex generator (4) on the surface of the blade, a high-energy induced vortex is generated on the surface of the blade by the vortex generator (4), thereby destroying the boundary layer of the fluid surface and making the surface turbulent. In the turbulent environment, the shear force on the droplets will be greater than the adhesion force, and the droplets cannot be adsorbed on the surface of the blade to form a water film, thereby achieving the purpose of active anti-icing on the blade surface.

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