Wind power blade surface modification system based on bionic feathers and pneumatic optimization method thereof

Abstract

The invention provides a wind power blade surface modification system based on bionic feathers and a pneumatic optimization method thereof.The wind power blade surface modification system comprises bionic feather units, the bionic feather units are arranged on the windward side, the blade tip area or the area from the front edge to the middle of a blade through a flexible substrate adhesion layer, and the bionic feather units passively deflect or actively adjust the form through an intelligent material; each bionic feather unit is provided with a sawtooth-shaped feather edge type structure, a fiber bundle down feather type structure, a fish scale overlapping type feather piece structure, a fan-shaped feather shaft comb-shaped structure or an intelligent response type corrugated feather piece bionic structure. Dynamic pneumatic regulation and control and noise reduction are achieved through modular arrangement of multiple types of bionic feather units in combination with a flexible substrate and an intelligent response coating, and a zigzag feather edge type, a fiber bundle down type, a fish scale overlapping type, a fan-shaped feather axis comb type and an intelligent response corrugated feather piece bionic feather structure are adopted; a flexible substrate is attached to a blade, and form self-adjustment is achieved through a heat / humidity sensitive material; and the feather combination can be customized according to the leaf area function requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation, and in particular to a wind turbine blade surface modification system based on bionic feathers and an aerodynamic optimization method thereof. Background Art

[0002] As wind turbine installed capacity increases, the size of wind turbine blades continues to increase, posing significant challenges to their aerodynamic performance and operational stability. Existing technologies are prone to problems such as boundary layer separation and vortex excitation in complex wind fields, leading to energy loss, increased noise, and structural fatigue. While biomimetic technologies have attempted to incorporate fixed structures (such as those modeled on the leading edge of a whale tubercle and beetle microstructures), these have mostly employed rigid, static designs that struggle to dynamically respond to changing wind conditions, lack flexible dynamic response capabilities, and suffer from drawbacks such as limited reliability and complex manufacturing.

[0003] In nature, the flexible vortex reduction and adaptive airflow control mechanisms of bird feather structures (such as serrated leading edges and flexible fibers) can effectively control airflow, reduce drag and noise, and provide new ideas for blade optimization. However, existing technologies have not yet achieved a deformable, responsive, and modular bionic surface system. Summary of the Invention

[0004] The purpose of the present invention is to provide a wind turbine blade surface modification system based on bionic feathers and its aerodynamic optimization method, aiming to develop a flexible, intelligently responsive, and easy-to-install bionic surface system to solve the problems of insufficient aerodynamic control, high noise, and high structural rigidity in the existing technology. Through the bionic feather structure, aerodynamic performance improvement, noise reduction optimization, and environmental adaptive adjustment can be achieved, while ensuring lightweight, easy maintenance, and system compatibility.

[0005] According to one object of the present invention, the present invention provides a wind turbine blade surface modification system based on bionic feathers, including a bionic feather unit, wherein the bionic feather unit is arranged on the windward surface of the blade, the tip area or the leading edge to the middle area through a flexible base adhesion layer, the bionic feather unit passively deflects or actively adjusts its shape through intelligent materials, and the bionic feather unit is arranged in a longitudinal array, a transverse grouping or a grid-like multi-directional arrangement; the bionic feather unit has a serrated feather edge structure, a fiber bundle down structure, a fish scale overlapping vane structure, a fan-shaped feather shaft comb structure or an intelligent response type corrugated vane bionic structure.

[0006] Furthermore, the flexible base adhesion layer is composed of polyurethane, polyimide or fluororubber elastic polymer, and the back of the flexible base adhesion layer is provided with weather-resistant glue or pressure-sensitive glue for firmly adhering to the surface of the blade. The temperature resistance range of the flexible base adhesion layer is -40℃~100℃, and the back adhesive layer is aviation-grade weather-resistant glue or pressure-sensitive glue with an adhesion strength ≥1.5MPa.

[0007] Furthermore, the serrated feather edge structure is in the form of a narrow strip, with a leading edge serration depth of 2~4mm and a period of 5~8mm. The surface is coated with a hydrophobic layer and is arranged in groups laterally along the tip area of ​​the blade, with a spacing of 8cm between each group and an angle of 10°~30° with the airflow. It is adhered to the blade surface by a two-component structural adhesive or UV-curing epoxy adhesive.

[0008] Furthermore, the backbone of the fiber bundle down-type structure is a PI film or a flexible substrate, the fiber bundle has a diameter of 50~150μm and a length of 1~3mm, and each unit contains 20~40 fiber bundles, which are randomly or symmetrically arranged and arranged in a longitudinal array from the root to the middle of the blade, with a spacing of 2~10cm, and an allowable swing angle of ±15°~±20°.

[0009] Furthermore, the fish-scale overlapping vane structure is a semi-elliptical or teardrop-shaped thin sheet, which is arranged overlappingly along the airflow direction, and the overlapping part accounts for 20% to 30% of the vane area. ETFE or bio-based composite materials are used to shorten the separation bubble length by 20% to 30%.

[0010] Furthermore, the fan-shaped feather shaft comb-like structure includes a carbon fiber main shaft and flexible feathers, and the central main shaft is connected to the swinging comb-tooth-shaped feathers with an opening angle of 40°~60°, which is used to suppress turbulence in medium and high wind speed areas.

[0011] Furthermore, the intelligent responsive corrugated vanes adopt SEBS-based corrugated membrane, with PNIPAm or shape memory polymer coating on the surface, with a corrugation period of 1~3mm and an amplitude of 0.2~0.6mm. When the wind speed is greater than 12m / s, it automatically adheres to the blade surface and opens to enhance turbulence when the temperature is greater than 35℃.

[0012] Furthermore, the arrangement of the bionic feather unit includes: Arranged in a longitudinal array, equidistant from the blade root to the blade tip; Arranged in groups horizontally, divided into outer edge suppression group, middle diversion group, and trailing edge noise reduction group according to functional areas; The feathers are arranged in a grid-like multi-directional pattern, with adjacent feather units staggered diagonally and overlapping by 20%.

[0013] According to another object of the present invention, the present invention provides an aerodynamic optimization method for the above-mentioned wind turbine blade surface modification system based on bionic feathers, comprising the following steps: S1. Determine the preset layout of the bionic feather units based on the functional requirements of the blade area, arranging noise-reducing feathers in the tip area and flow-guiding feathers in the middle area; S2. Overlap or gradient arrange the bionic feather units along the airflow direction to form a microstructured spoiler belt.

[0014] Furthermore, it also includes S3, spraying a heat / humidity-sensitive responsive coating on the surface of the feather unit to achieve adaptive deformation when the wind speed is greater than 12m / s or the temperature is greater than 35℃; the intelligent responsive corrugated feathers reduce the drag coefficient by 2.5% when the wind speed is greater than 12m / s, and enhance the turbulence by opening the structure when the temperature is greater than 35℃.

[0015] The technical solution of the present invention realizes dynamic aerodynamic control and noise reduction through the modular arrangement of multiple types of bionic feather units, combined with a flexible substrate and an intelligent response coating. It adopts five bionic feather structures: serrated feather edge type, fiber bundle down type, fish scale overlapping type, fan-shaped feather shaft comb type, and intelligent response corrugated feather. The feather unit is attached to the blade through a flexible substrate and uses heat / humidity sensitive materials to achieve self-adjustment of shape. The feather combination can also be customized according to the functional requirements of the blade area. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a schematic structural diagram of a bionic feather unit and a flexible base adhesion layer according to an embodiment of the present invention; Figure 2 This is a schematic structural diagram of a bionic feather unit and blades according to an embodiment of the present invention; Figure 3 This is another structural schematic diagram of the bionic feather unit and blades according to an embodiment of the present invention; Figure 4 Schematic diagram of another structure of the bionic feather unit and blades according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of a bionic feather used in an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of a bionic feather when used on a blade according to an embodiment of the present invention; In the figure, 1. blade; 2. flexible base adhesion layer; 3. bionic feather unit; 301. serrated feather edge type feather; 302. fiber bundle down type feather; 303. fish scale overlapping vane feather; 304. fan-shaped feather shaft comb-shaped feather. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the present invention.

[0020] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a communication between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0021] Example 1 like Figures 1-6 As shown, a wind turbine blade surface modification system based on bionic feathers includes: Bionic Feather Unit 3: Features a variety of bionic structures, including serrated feather edges, fiber bundle down, and fish-scale overlapping feathers. Made of flexible materials such as TPU and PI, with a thickness of less than 1.5mm, it can passively deflect or actively adjust its shape through intelligent materials. Flexible base adhesive layer 2: Made of elastic polymers such as polyurethane and polyimide, with weather-resistant adhesive on the back to achieve firm adhesion to the blade surface; Installation interface and additional structure: arranged on the windward side or tip area of ​​blade 1, using adhesion, slotting, magnetic attraction and other installation methods, and optional hot melt adhesive tape or mechanical buckle to enhance fixation; The bionic feather units 3 are arranged in a longitudinal array, transverse grouping or grid-like multi-directional manner. They disturb the airflow, suppress separation, and break up the noise generation mechanism through microstructures. At the same time, they have anti-fouling, self-cleaning and dynamic load reduction functions.

[0022] This invention improves the aerodynamic performance of the blade. The serrated feather edge structure can increase the lift coefficient by 6% to 9% and reduce the drag coefficient by more than 3%. The overlapping fish-scale structure shortens the separation bubble length by 20% to 30%. The invention also has a significant noise reduction effect. The fiber bundle down-like structure reduces noise by 2 to 4 dB (A) in the 5 to 12 kHz frequency band, and the combined arrangement can interrupt the vortex generation chain. The invention has an adaptive adjustment function, and the intelligent response coating realizes structural deformation triggered by wind speed and temperature, with a response time of less than 0.5 seconds.

[0023] Specifically, the bionic feather unit of the present invention has a variety of bionic structures such as serrated feather edges, fiber bundle down, and fish scale overlapping feathers. Its specific application areas and characteristics are as follows: 1. Application of serrated feather edge structure in the tip area Structural design: The feather unit is in the shape of a narrow strip, with a leading edge serration depth of 3mm and a period of 6mm. It is made of TPU material and coated with a hydrophobic layer.

[0024] Arrangement: Arrange in groups horizontally along the blade tip area, with a spacing of 8 cm between each group and an angle of 20° with the airflow.

[0025] Installation method: Adhere to the blade surface through two-component structural adhesive, the thickness of the flexible base is 0.5mm.

[0026] Functional effect: At a wind speed of 12m / s, the vortex noise in the blade tip area is reduced by 3dB (A) and the lift coefficient is increased by 7%.

[0027] 2. Application of fiber bundle down structure in low wind speed areas Structural design: The main body is PI film, the fiber bundle has a diameter of 100μm and a length of 2mm. Each feather contains 30 bundles of fibers, which are randomly arranged.

[0028] Arrangement: Arranged in a longitudinal array from the root to the middle of the leaf, with a spacing of 5 cm and a feather length of 8 cm.

[0029] Installation method: UV-curing epoxy adhesive bonding, flexible connection structure allows ±15° swing.

[0030] Functional effect: At a wind speed of 6m / s, the boundary layer adhesion stability is improved and the wind energy capture efficiency is increased by 5%.

[0031] 3. Adaptive adjustment of intelligent responsive corrugated vanes Structural design: The corrugated film is made of SEBS material and coated with PNIPAm coating on the surface. The corrugation period is 2mm and the amplitude is 0.4mm.

[0032] Arrangement: Grid-like multi-directional arrangement in the middle of the blade, covering 15% of the area.

[0033] Functional effect: When the wind speed is greater than 12m / s, the corrugated structure automatically adheres to the blade surface, reducing the drag coefficient by 2.5%; when the temperature is greater than 35℃, the structure opens to enhance turbulence.

[0034] Example 2 like Figures 1-6 As shown, the structure of this embodiment is basically the same as that of the above embodiment. The difference is that, in this embodiment, the wind turbine blade surface modification system based on bionic feathers includes a bionic feather unit 3, a flexible base adhesion layer 2 and a blade mounting interface, and the bionic feather unit is fixed to the blade mounting interface through the flexible base adhesion layer.

[0035] In this embodiment, the bionic feather unit 3 is connected to the flexible base adhesive layer 2 via a flexible material, allowing a swing angle of ±20° to adapt to the direction of airflow.

[0036] In this embodiment, the bionic feather unit 3 is in the shape of an elongated strip or a crescent, with a thickness of less than 1.5 mm, a sawtooth, fibrous or corrugated microstructure on the upper surface, and a cavity structure inside.

[0037] The bionic feather unit includes at least one of the following types: Serrated feather 301: The leading edge is an equidistant serrated edge with a serration depth of 2-4mm and a period of 5-8mm. It is made of TPU hot pressing. Fiber bundle down feather 302: The main strips are distributed with fiber bundles of 50-150μm diameter and 1-3mm length, with 20-40 bundles per unit, and UV curing bonding; Fish scale overlapping vane feather 303: arranged in overlapping arrangement along the airflow direction, semi-elliptical thin slices overlap, the overlapping part accounts for 20%~30% of the vane area, ETFE material; Fan-shaped feather shaft comb-like feather 304: It consists of a carbon fiber main shaft and flexible barbs. The central main shaft is connected to the swingable comb-like barbs with an opening angle of 40°~60°. It is 3D printed in one piece. Smart Responsive Corrugated Vanes: A SEBS-based corrugated membrane (period 1-3mm) embedded with a PNIPAm responsive layer features multi-scale surface corrugations and is coated with a shape memory polymer. The responsive material is PNIPAm or a shape memory polymer, and the trigger temperature is 35°C or a wind speed of 12m / s. Adaptive adjustment: When wind speeds exceed 12m / s, the corrugated vanes automatically adhere to the surface; when temperatures exceed 35°C, the vanes retract to reduce the windward area.

[0038] In this embodiment, the flexible base adhesive layer 2 is made of polyurethane, polyimide or fluororubber, and is provided with weather-resistant adhesive or pressure-sensitive adhesive on the back thereof, with a temperature resistance range of -40°C to 100°C.

[0039] In this embodiment, the blade installation interface is the windward surface of the blade, the tip area, or the area from the leading edge to the middle, and the coverage area is 10% to 25% of the total area of ​​the blade 1.

[0040] In this embodiment, an additional anchoring structure is also included, and the additional anchoring structure is a hot melt adhesive reinforcement belt, a micro-mechanical buckle or a surface nano-layer modified area.

[0041] In this embodiment, an intelligent response coating is also included. The intelligent response coating is PNIPAm, a thermoresponsive polymer or a moisture-responsive polymer, which realizes structural adaptive deformation triggered by temperature and wind speed, and is used to trigger the morphological adjustment of the bionic feather unit.

[0042] The arrangement of the bionic feather units includes longitudinal array arrangement, transverse group arrangement or grid-like multi-directional arrangement. Through microstructure, the airflow is disturbed, separation is suppressed, and noise generation mechanism is broken up. At the same time, it has anti-fouling, self-cleaning and dynamic load reduction functions. Specifically, the longitudinal array arrangement is arranged equidistantly from the root to the tip of the blade, and the transverse group arrangement is divided into outer edge suppression group, middle guide group and trailing edge noise reduction group according to functional areas. In the grid-like fish scale arrangement, adjacent feather units are staggered obliquely and overlap by 20%.

[0043] Installation steps of the bionic feather-based wind turbine blade surface modification system: Clean the blade surface; Paste the feather units onto the flexible substrate according to the optimized layout; The whole is fitted from the leading edge to the middle area of ​​the blade; Add additional hot melt tape to reinforce the edges.

[0044] The aerodynamic optimization method of the wind turbine blade surface modification system based on bionic feathers includes the following steps: Fixing the bionic feather units on the flexible substrate according to a preset layout; The substrate is bonded to the windward side of the blade using pressure-sensitive adhesive; the bionic feather units are overlapped or arranged in a gradient along the airflow direction to form a microstructured spoiler belt; A heat- and humidity-sensitive coating is sprayed onto the feather unit surface. This intelligent coating enables the bionic feather unit to adaptively deform in response to wind speed and temperature, adjusting its aerodynamic state. The coating triggers adaptive morphology adjustment of the feather unit when temperatures exceed 35°C or wind speeds exceed 12m / s.

[0045] Among them, the preset layout is determined according to the functional requirements of the blade area, with noise-reducing feathers arranged in the tip area and flow-guiding feathers arranged in the middle area.

[0046] Specifically, the method further includes reinforcing the edges of the feather units by means of hot-melt adhesive tape.

[0047] In this aerodynamic optimization method, the laying methods of the bionic feather unit include adhesion method, grooving method or magnetic attraction method, among which the grooving method fixes the bionic feather unit through the reserved grooves in the blade mold.

[0048] The arrangement parameters of the bionic feather units include: feather length 1~15cm, spacing 2~10cm, and angle with the airflow 10°~30°.

[0049] The present invention realizes dynamic aerodynamic control and noise reduction through the modular arrangement of multiple types of bionic feather units, combined with a flexible substrate and an intelligent response coating. It adopts five bionic feather structures: serrated feather edge type, fiber bundle down type, fish scale overlapping type, fan-shaped feather shaft comb type, and intelligent response corrugated feather. The feather unit is attached to the blade through a flexible substrate and uses heat / humidity sensitive materials to achieve self-adjustment of shape. The feather combination can also be customized according to the functional requirements of the blade area.

[0050] Example 3 like Figures 1-6 As shown, this embodiment has essentially the same structure as the previous one. The difference lies in this embodiment's bionic feather-based wind turbine blade surface modification system, which effectively enhances wind energy capture, improves flow boundary layer characteristics, and reduces operating noise without compromising the blade's structural integrity and dynamic balance. This system achieves aerodynamic optimization and enhanced noise reduction on the wind turbine blade surface through the synergistic effects of flexible materials, microstructure design, and intelligent response capabilities.

[0051] This method draws on the ability of bird feathers to regulate airflow during flight. By laying bionic feather structures on the surface of wind turbine blades, the aerodynamic performance of the blades is improved, thereby enhancing wind energy capture efficiency and reducing operating noise, achieving the unity of performance improvement and eco-friendliness.

[0052] This invention utilizes high-performance flexible materials to construct a bionic feather unit structure, which exhibits a certain degree of elasticity and weather resistance. These bionic structures are evenly distributed on the windward side and tip of the wind turbine blade according to a specific arrangement pattern (such as a fish-scale-like overlapping arrangement or a gradient arrangement along the airflow direction). Each bionic unit features feather-like micro-bristles and cilia, which effectively regulate boundary layer airflow, delay airflow separation, and reduce vortex intensity, thereby improving wind energy utilization efficiency.

[0053] The bionic feather structure also offers noise reduction benefits. By optimizing the feather's microstructure (e.g., micro-serrated edges and bifurcated fiber bundles), a biological-like flow pattern is created as air flows through the blades, disrupting the generation of high-frequency noise and effectively reducing wind shear and rotational noise. Furthermore, the bionic structure does not significantly increase blade mass or wind resistance, ensuring the overall operational safety and economic efficiency of the system.

[0054] To adapt to varying wind conditions, the present invention can also incorporate intelligent sensing materials or responsive coating technologies to achieve active adjustment of the feather structure. For example, the use of thermo- or moisture-responsive materials could enable the biomimetic structure to automatically expand or contract under varying weather conditions, further improving operational efficiency and environmental adaptability.

[0055] While keeping the existing wind turbine blade structure basically unchanged, the present invention gives it multifunctional characteristics through surface bionic modification. It has the advantages of high design flexibility, strong adaptability, and controllable costs. It is suitable for various types of onshore and offshore wind turbines and has good prospects for promotion and application.

[0056] Specifically, in this embodiment, the bionic feather-based wind turbine blade surface modification system mainly includes the following components: a bionic feather unit, a flexible base adhesion layer, a blade surface mounting interface, an additional bonding / anchoring structure, and an intelligent response coating. Part I Bionic Feather Unit 1. Bionic feather unit structure and type The bionic feather unit is long or crescent-shaped, with an overall thickness of less than 1.5 mm, a length of 1 to 15 cm, and a width of 310 mm. The upper surface has a serrated or fibrous microstructure, simulating the noise reduction features of bird feathers such as the crest and mane. The interior of the unit can be a cavity structure to reduce weight and enhance flexibility.

[0057] The bionic feather unit 3 has the ability to deflect along the airflow and can passively adhere to the blade surface under strong winds to reduce resistance; in low wind speed or turbulent environments, the microstructure can stabilize the boundary layer airflow, suppress turbulence, and delay separation.

[0058] The bionic feather unit 3 features several different bionic feather structure shapes, each optimized for a specific wind turbine blade operating area, aerodynamic control objectives, or material forming process. These structures can be applied individually or in combination to the surface of a wind turbine blade to maximize its aerodynamic efficiency and noise reduction: (1) Sawtooth feather-edge bionic structure 1. Structure description: Simulate the serrated edge of the feathers on the leading edge of an owl's wing; the feather unit is a narrow strip with an equidistant serrated edge on the leading edge (serration depth 2-4 mm, period 5-8 mm); the trailing edge is naturally curved to fit the curvature of the blade surface.

[0059] 2. Applicable functions: Reduce eddy current noise and enhance boundary layer stability; suitable for the area from the middle to the tip of the blade, especially the high-speed rotation area.

[0060] 3. Material selection: Made of thermoplastic polyurethane (TPU) material, it can be hot-pressed and molded; the surface can be coated with a low-adhesion hydrophobic layer to enhance anti-pollution capabilities.

[0061] (2) Fiber bundle down type structure 1. Structure description: The microfiber structure simulates that of bird down; vertical outward fiber bundles are distributed on the main stripes, each fiber bundle has a diameter of 50~150μm and a length of 1~3mm; each feather contains 20\~40 bundles, and the fibers can be arranged randomly or symmetrically.

[0062] 2. Applicable functions: Disturbs the boundary layer micro-airflow and enhances the stability of the viscous adhesion layer; it is especially suitable for enhancing air capture capabilities at low wind speeds.

[0063] 3. Material selection: The main body uses flexible PI film, and the fibers are electrospun polyester nanofilaments or bionic nylon filaments; the bonding adopts UV-curing epoxy glue or one-piece injection molding process.

[0064] (3) Fish scale overlapping pinna structure 1. Structure description: Each feather unit is a semi-elliptical or teardrop-shaped thin sheet; multiple vanes are arranged overlappingly along the direction of airflow, forming a fish-scale paving structure; the thickness of each feather is less than 0.8 mm, and the overlapping part accounts for about 20%~30% of the vane area.

[0065] 2. Applicable functions: Similar to an assembled flow inducer, it improves the ability to guide the airflow and alleviates separation bubbles; it is suitable for the transition zone from the root to the middle of the blade to enhance aerodynamic smoothness.

[0066] 3. Material selection: Made of highly weather-resistant transparent fluoropolymers (such as ETFE) or bio-based composites; suitable for modular replacement and blade maintenance operations.

[0067] (4) Fan-shaped feather shaft comb-like structure 1. Structure description: Each bionic feather consists of a central main axis (rachis) and several diagonally arranged comb-like barbs; the barbs can swing and deform freely when hit by airflow, forming an adjustable "open / close" structure; the total width is about 30\~50 mm, and the fan-shaped opening angle is about 40°~60°.

[0068] 2. Applicable functions: It has a significant dynamic adjustment effect and is suitable for suppressing turbulence in medium and high wind speed areas; it can play a role in regulating aerodynamic impedance similar to a "wind gate".

[0069] 3. Material selection: The main shaft is made of carbon fiber reinforced plastic, and the feathers are made of flexible TPU or PVDF thin strips, which can be formed in one piece through 3D printing.

[0070] (5) Intelligent aerodynamic response corrugated vanes 1. Structure description: The feather structure adopts a flexible corrugated film design; the surface of the film has a multi-scale corrugated pleat structure (period 1~3mm, amplitude 0.2~0.6mm); combined with smart materials (such as PNIPAm, shape memory polymers), it can self-adjust its shape when the wind speed or temperature changes.

[0071] 2. Applicable functions: Achieve adaptive aerodynamic response adjustment, automatically adhere at high wind speeds and slightly lift at low wind speeds; automatically optimize aerodynamic status under different wind field conditions.

[0072] 3. Material selection: The corrugated membrane material is a highly elastic copolymer (such as SEBS), and the responsive material is a thermosensitive polymer or an electroactive material; it can be used in the development of the next generation of smart blades.

[0073] 2. Classification of Bionic Feather Unit Arrangement The bionic feather structure of this invention is designed to simulate the airflow regulation ability of bird feathers during flight, thereby improving the aerodynamic performance and noise reduction capabilities of wind turbine blades. Its layout design must consider the following key objectives: conforming to the direction of airflow, reducing turbulence and noise; improving the efficiency of wind energy capture on the blade surface; maintaining stable structural attachment and strong wind resistance; and being compatible with existing wind turbine blade manufacturing and maintenance processes. Specifically, the following layout methods are included: (1) Vertical array arrangement Layout position: longitudinally arranged along the windward or leeward side of the wind turbine blade, that is, arranged from the root to the tip of the blade; Arrangement form: equidistant straight line arrangement or adjusting the spacing according to the curvature of the blade shape; Applicable scenarios: Suitable for large-scale blades to enhance the overall airflow control capability; Advantages: It helps to form a stepped or fin-shaped spoiler structure and improve the boundary layer adhesion state.

[0074] (2) Horizontal grouping arrangement Arrangement position: Several groups of feather units are arranged horizontally from the middle to the tip of the blade surface; Arrangement: divided into outer edge suppression group, middle diversion group, and trailing edge noise reduction group according to function; Features: Feather groups with different functions can be replaced by modular pasting or embedding; Advantages: Easier to maintain, can achieve locally enhanced wind capture or noise suppression.

[0075] (3) Grid-like multi-directional layout Arrangement: arranged in an oblique / fish-scale pattern on the leaf surface, forming partial overlap or staggered patterns; Implementation method: Using flexible base material to form a camouflage structure; Advantages: Enhance surface micro-disturbance and improve overall wind energy utilization; Typical shape: Imitating the structure of raptor wings, with high dynamic response capability.

[0076] 3. Bionic Feather Unit Installation Structure The bionic feather unit has the following fixing methods: (1) Base fixing method Adhesion method: Use a weather-resistant two-component structural adhesive or pressure-sensitive adhesive to stick the bionic feather base to the blade surface; Grooving method: a groove is reserved in the blade mold, and the feather structure is embedded in the groove and fixed with mechanical clips or screws; Magnetic adsorption method (for metal blades or specific parts): The base contains a magnetic adsorption layer.

[0077] (2) Flexible connection design Each set of feathers is connected to the base through flexible materials (such as polyurethane and elastic silicone), forming a swing angle with a certain degree of freedom; this structure can undergo slight adjustments under the action of strong winds to adapt to the direction of airflow and reduce fluid resistance and stress concentration.

[0078] 4. Example of Bionic Feather Unit Arrangement Parameters As shown in Table 1, the layout parameters of the bionic feather unit are described. Table 1 Layout parameters of bionic feather units

[0079] 5. Working Principle of Bionic Feather Unit When wind blows through the bionic feather structure, its shape and material will produce tiny vibrations, turbulence, and lift adjustment. Disturbing effect: breaking the boundary layer laminar flow and preventing airflow from escaping the body; Noise reduction effect: Similar to the structure of owl feathers, it reduces blade eddy current noise; Dynamic adjustment: When the wind speed increases, the feathers bend slightly to reduce the windward area, forming an adaptive load reduction function; Anti-fouling and self-cleaning: The feather structure has a slightly curved or scaly surface to reduce the accumulation of dust and the adhesion of rain and snow.

[0080] 6. Compatibility of the Bionic Feather Unit with Other Blade Systems Compatible with traditional blade materials (glass fiber reinforced plastics, carbon fiber composite materials); can be customized according to the blade mold integrated design or later glued; does not affect the overall dynamic balance design of the blade.

[0081] Second part: flexible base adhesive layer The flexible base adhesive layer 2 is made of an elastic polymer film (such as polyurethane (PU), polyimide (PI), or fluororubber); the back side is provided with a high-performance aviation-grade weather-resistant adhesive or pressure-sensitive adhesive for adhesion to the blade surface; and it has good bending properties and thermal stability (temperature resistance range -40°C to 100°C).

[0082] Part 3 Installation interface and additional structure The installation interface is the windward side or blade tip area of ​​the wind turbine blade, and is preferably placed from the leading edge to the middle area of ​​the blade, with the coverage area generally being 10% to 25% of the total blade area; Additional anchoring structures include hot-melt adhesive reinforcement strips, micromechanical clips (for replaceable structures), or surface nano-layer modified areas (to enhance adhesion).

[0083] Part 4: Smart Response Coating Shape memory polymer materials or heat / humidity responsive polymer layers (such as PNIPAm) are sprayed on the outer surface of the bionic structure or substrate to adaptively adjust the structural morphology. When the temperature rises, the humidity changes, or the wind speed changes, the response layer can trigger the opening, closing, or contraction of the bionic structure to achieve dynamic aerodynamic adjustment.

[0084] Part 5 Structural Connection Relationship The bionic feather unit is firmly attached to the blade surface through a flexible base adhesion layer; multiple feather units are arranged in an overlapping fish-scale pattern or downstream to ensure the continuity of airflow transition; a spacing of 2 to 10 cm is set between each row of feathers to prevent air blockage and the risk of falling off; the intelligent response coating or anchoring structure is integrated with the base to ensure long-term stability.

[0085] Part VI Working Principles and Methods (1) Working principle: When the wind flows into contact with the wind turbine blades, the bionic feather unit deflects in the downwind direction; the micro-serrations and ciliary structures disturb the airflow, inhibit boundary layer separation, and reduce the frequency of tail vortex shedding; in the high-speed rotation area of ​​the blade tip, the feather structure disperses aerodynamic waves and weakens high-frequency eddy noise; the intelligent response layer adjusts the feather angle according to wind speed and temperature to achieve adaptive surface control.

[0086] (2) Working methods: The bionic feather structure can be installed by adhesive or replaced modularly when the finished blades leave the factory or during wind farm operation and maintenance. Installers will develop a suitable layout plan based on the blade model, wind farm environment and simulation optimization results. All structures are verified by UV aging, marine corrosion and low-temperature impact tests.

[0087] Part 7 Material Selection As shown in Table 2, the material selection for the bionic feather unit Table 2 Material selection description of bionic feather unit

[0088] Part 8: Reasonableness and Scientificity The principles of bionic design are mature, and existing literature has confirmed the regulatory effect of feather / fish scale structures on the flow field; the materials can be industrially prepared, such as hot pressing micro-forming and laser cutting; the layout method matches the mechanics of wind turbine blades and will not cause structural imbalance or overload; it has the advantages of low cost and high performance, and is feasible for upgrading existing wind farms.

[0089] The bionic feather surface modification system proposed in this invention systematically optimizes the aerodynamic control and noise reduction requirements of wind turbine blade surfaces by introducing a multi-type, functionally partitioned bionic feather structure. Compared with existing technologies that only use single-structure spoilers or shaped guide vanes, it has the following significant technical advantages: 1. Significant improvement in aerodynamic performance: The serrated vane structure of this invention effectively simulates the turbulence characteristics of an owl's wing leading edge. By forming a serrated edge with a period of 5-8 mm and a depth of 2-4 mm, it improves boundary layer adhesion stability. Experimental simulations show that at wind speeds of 10-15 m / s, the blade's local lift coefficient can be increased by 6%-9% and the drag coefficient can be reduced by more than 3%. The overlapping fish-scale vane structure in the central region of the blade can simulate the effect of a prefabricated flow inducer, promoting airflow reattachment and shortening the separation bubble length by approximately 20%-30%, significantly improving aerodynamic smoothness.

[0090] 2. Noise reduction effect is better than traditional solutions: Compared to traditional trailing-edge serrated noise reduction blades, the present invention's fiber bundle down-shaped and fan-shaped rachis comb-like structure reduces high-frequency acoustic loss in the 5-12kHz frequency range, reducing noise power levels by 2-4 dB(A). The optimal noise suppression effect is achieved when the fiber bundle diameter is controlled between 50-150 μm. The combination of multiple biomimetic structures creates a "multi-scale perturbation zone" at the rotor blade tip, disrupting the vortex generation chain and reducing vortex shedding noise at the source.

[0091] 3. Strong downwind response and structural adaptability: The present invention's corrugated vane structure incorporates a PNIPAm-type thermoresponsive material, enabling deformation and attachment at temperatures above 35°C or wind speeds exceeding 12 m / s. This adaptive deformation threshold response allows for automatic adjustment of wind pressure on the windward side of the blade. The fan-shaped vane structure acts as a "damper" under dynamic wind speed fluctuations. Test data shows that the vane opening and closing response time is less than 0.5 s within a wind speed range of 7 to 15 m / s, demonstrating excellent dynamic response characteristics.

[0092] 4. Lightweight and flexible design reduces load risks: The feather units of this invention have an overall thickness of 0.8 to 1.5 mm and are made of lightweight, highly elastic materials such as TPU, PI, and ETFE. The unit area-to-weight ratio is less than 0.25 kg / m², which does not affect the overall dynamic balance of the wind rotor and is resistant to peeling or breaking under strong winds. The fiber bundle feather structure has an average compliance coefficient of approximately 0.65 (approximately 30% higher than that of pure TPU material), making it suitable for bonding to curved blade surfaces with large curvatures.

[0093] 5. Easy maintenance and good system compatibility: The system of the present invention supports multiple installation methods such as adhesion, grooving, and magnetic attraction. It is suitable for fiberglass or carbon fiber reinforced composite blades. It can be integrated with the existing blade mold prefabrication process, or it can be modularly pasted later. In actual tests, the wind peel strength of the grooving installation structure is higher than 1.5 MPa. The flexible connection angle range between the feather unit and the base reaches ±20°, and it has anti-vibration buffering capabilities, effectively alleviating the problem of local stress concentration caused by high-speed rotation. By optimizing the design of the feather microstructure, a biological-like flow state can be formed when air flows through the blade, breaking up the generation mechanism of high-frequency noise and effectively reducing wind shear noise and rotational noise.

[0094] In summary, the present invention has made significant progress in bionic aerodynamic control, noise reduction, structural adaptability and system integration compared with existing blade surface spoilers or noise reduction accessories, and can be widely used in the development of new high-efficiency and low-noise wind turbine blades and the upgrading and transformation of old blades.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wind turbine blade surface modification system based on bionic feathers, characterized in that: The bionic feather unit comprises a bionic feather unit, which is arranged on the windward side of the blade, the tip area or the leading edge to the middle area through a flexible base adhesion layer. The bionic feather unit passively deflects or actively adjusts its shape through intelligent materials. The bionic feather unit has a serrated feather edge structure, a fiber bundle down structure, a fish scale overlapping feather structure, a fan-shaped feather shaft comb structure or an intelligent response corrugated feather bionic structure.

2. The wind turbine blade surface modification system based on bionic feathers according to claim 1 is characterized in that: The flexible base adhesion layer is composed of polyurethane, polyimide or fluororubber elastic polymer. The back of the flexible base adhesion layer is provided with weather-resistant glue or pressure-sensitive glue for firmly adhering to the surface of the blade. The temperature range of the flexible base adhesion layer is -40℃~100℃, and the back adhesive layer is aviation-grade weather-resistant glue or pressure-sensitive glue with an adhesion strength of ≥1.5MPa.

3. The wind turbine blade surface modification system based on bionic feathers according to claim 1 is characterized in that: The serrated feather edge structure is in the form of a narrow strip, with a leading edge serration depth of 2 to 4 mm and a period of 5 to 8 mm. The surface is coated with a hydrophobic layer and arranged in groups laterally along the tip area of ​​the blade, with a spacing of 8 cm between each group and an angle of 10° to 30° with the airflow. It is adhered to the blade surface by a two-component structural adhesive or a UV-curing epoxy adhesive.

4. The wind turbine blade surface modification system based on bionic feathers according to claim 1, characterized in that: The backbone of the fiber bundle down-type structure is a PI film or a flexible substrate. The fiber bundle has a diameter of 50 to 150 μm and a length of 1 to 3 mm. Each unit contains 20 to 40 fiber bundles, which are randomly or symmetrically arranged in a longitudinal array from the root to the middle of the blade, with a spacing of 2 to 10 cm and an allowable swing angle of ±15° to ±20°.

5. The wind turbine blade surface modification system based on bionic feathers according to claim 1, characterized in that: The fish-scale overlapping vane structure is a semi-elliptical or teardrop-shaped thin sheet, which is arranged overlappingly along the airflow direction. The overlapping part accounts for 20% to 30% of the vane area. ETFE or bio-based composite materials are used to shorten the separation bubble length by 20% to 30%.

6. The wind turbine blade surface modification system based on bionic feathers according to claim 1, characterized in that: The fan-shaped feather shaft comb structure includes a carbon fiber main shaft and flexible feathers. The central main shaft is connected to the swinging comb-shaped feathers with an opening angle of 40°~60°, and is used to suppress turbulence in medium and high wind speed areas.

7. The wind turbine blade surface modification system based on bionic feathers according to claim 1, characterized in that: The intelligent responsive corrugated vanes adopt SEBS-based corrugated membrane with PNIPAm or shape memory polymer coating on the surface. The corrugation period is 1-3mm and the amplitude is 0.2-0.6mm. When the wind speed is greater than 12m / s, the vanes automatically adhere to the blade surface and open to enhance turbulence when the temperature is greater than 35℃.

8. The wind turbine blade surface modification system based on bionic feathers according to claim 1, characterized in that: The arrangement of the bionic feather unit includes: Arranged in a longitudinal array, equidistant from the blade root to the blade tip; Arranged in groups horizontally, divided into outer edge suppression group, middle diversion group, and trailing edge noise reduction group according to functional areas; The feathers are arranged in a grid-like multi-directional pattern, with adjacent feather units staggered diagonally and overlapping by 20%.

9. The aerodynamic optimization method for a wind turbine blade surface modification system based on bionic feathers according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Determine the preset layout of the bionic feather units based on the functional requirements of the blade area, arranging noise-reducing feathers in the tip area and flow-guiding feathers in the middle area; S2. Overlap or gradient arrange the bionic feather units along the airflow direction to form a microstructured spoiler belt.

10. The aerodynamic optimization method of the wind turbine blade surface modification system based on bionic feathers according to claim 9, characterized in that: It also includes S3, which sprays a heat / humidity-sensitive responsive coating on the surface of the feather unit to achieve adaptive deformation when the wind speed is greater than 12m / s or the temperature is greater than 35℃; the intelligent responsive corrugated feathers reduce the drag coefficient by 2.5% when the wind speed is greater than 12m / s, and enhance the turbulence by opening the structure when the temperature is greater than 35℃.

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