Blade for improving wind power generation efficiency and design method
By combining biomimetic composite airfoils and adaptive guide vanes, the wind turbine blade structure was optimized, solving the problems of difficult start-up at low wind speeds and unstable power at high wind speeds, thus improving wind power efficiency and structural stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-20
- Publication Date
- 2026-04-03
AI Technical Summary
Traditional wind turbine blades are difficult to start under low wind speed conditions, which leads to increased downtime and significant annual power generation loss. Furthermore, under high wind speeds, they are prone to a sudden drop in lift and a surge in drag, resulting in unstable power output and structural vibration.
A biomimetic composite airfoil blade is designed, combining adaptive guide vanes and multi-objective genetic algorithm optimization. It disperses the airflow to increase the airflow velocity on the upper surface of the blade at low wind speeds and closes the airflow channel at high wind speeds. The blade structure is reinforced with glass fiber and carbon fiber composite materials.
The blades have increased maximum lift coefficient under low Reynolds number conditions, delayed stall angle of attack, expanded high-efficiency operating range, significantly improved starting torque and power generation capacity at low wind speeds, while ensuring overall stiffness and fatigue life.
Smart Images
Figure CN121782092A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of wind power generation technology, specifically to a blade and design method for improving wind power generation efficiency. Background Technology
[0002] As the global energy structure shifts towards cleaner and lower-carbon energy, wind energy, as a renewable energy source with abundant reserves and mature technology, is being developed and utilized in greater depth. In addition to the construction of large-scale wind power bases, small wind power systems suitable for distributed generation and off-grid power supply have increasingly broad application prospects in low-wind-speed resource areas. However, due to their smaller blade size, these small wind turbines typically operate at lower tip speed ratios and Reynolds numbers, which presents unique challenges to blade aerodynamic design and structural optimization compared to larger units.
[0003] Under low wind speed conditions (such as below the rated wind speed), the airfoil's lift coefficient is generally low, and laminar separation of airflow easily occurs on the airfoil surface, resulting in insufficient blade starting torque. This makes it difficult to start effectively at a cut-in wind speed of 3-4 m / s, increasing the turbine's downtime and significantly reducing annual power generation. When the wind speed rises to near the rated point or encounters turbulence, traditional airfoils have a smaller stall angle of attack, and the blades are prone to entering a deep stall state, causing a sharp drop in lift and a surge in drag. This not only leads to unstable and fluctuating power output but also triggers severe structural vibration and fatigue loads, threatening the unit's safety.
[0004] Therefore, the blade design of traditional wind turbines cannot guide airflow to the upper surface of the blade body at low wind speeds, thus making it impossible for the blades to drive the wind turbine hub to rotate and generate electricity when the wind speed is lower than the predetermined value, making it difficult to improve the power generation efficiency of wind turbines. Summary of the Invention
[0005] The purpose of this invention is to address the shortcomings and deficiencies of existing technologies by providing a blade and design method for improving wind power generation efficiency.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: a blade design method for improving wind power generation efficiency, comprising the following steps: S1. Determine the basic design parameters of the blade body: Based on the target unit power, rated wind speed, cut-in wind speed and low Reynolds number operating range, determine the number of blade bodies and the total length of the blade body; S2. Construct a biomimetic composite airfoil library: Using the albatross wing airfoil as a biomimetic prototype, determine the geometric characteristic parameters of the airfoil, and optimize the basic biomimetic airfoil at the target Reynolds number based on aerodynamic analysis software to form a composite airfoil with improved lift-to-drag ratio. S3. Global optimization of main leaf parameters based on multi-objective genetic algorithm: S31. Set optimization objectives with the core objectives of maximizing the lift coefficient, minimizing the total weight of the blade body, and maximizing fatigue life, while also constraining manufacturing costs. S32. Set the geometric parameters of the composite airfoil, the spanwise chord length and twist angle distribution parameters of the blade body, and the composite material layup ratio as optimization variables; S33. The NSGA-II genetic algorithm is used in conjunction with aerodynamic and structural simulation software to perform joint simulation optimization and obtain the optimal parameter combination. S4. Determine the geometric configuration of the blade body: Based on the optimal parameter combination obtained in step S3, determine the detailed chord length distribution and twist angle distribution of the blade body; S5. Design of adaptive passive guide vane: A guide vane is set at the leading edge of the blade body, and its hinge position and adaptive control logic are determined. The control logic enables the guide vane opening angle to be automatically adjusted with the wind speed. S6. Conduct composite structure design: For different functional areas of the blade body, design layup schemes using glass fiber, carbon fiber or their hybrid materials, and fill the blade body with core material.
[0007] A further improvement is made in step S1, where the target unit power is 100kW and the low Reynolds number operating range is Re=3×10. 5 - 8×10 5 The number of blade bodies is 3, and the total length of the blade bodies is 14.5m.
[0008] A further improvement is that, in step S2, the leading edge radius of the biomimetic prototype airfoil is 0.08 times the local chord length, the trailing edge thickness is 0.02 times the local chord length, and the maximum thickness is located at 25%-30% of the chord length.
[0009] A further improvement is that, in step S3, the optimization variables specifically include: the maximum thickness of the airfoil, the camber, the cubic polynomial coefficients of the chord length along the span, the twist gradient distribution parameters from the blade root to the blade tip, and the carbon fiber layup ratio in the blade tip region.
[0010] A further improvement is that in step S4, the chord length distribution satisfies the following: the chord length at the leaf root is 2.2m, the chord length at the leaf tip is 0.35m, and the chord length in the middle region gradually changes according to a cubic polynomial; the twist angle distribution satisfies the following: the twist angle at the leaf root is 18°, the twist angle at the leaf tip is 2°, the middle region gradually changes according to a linear formula, and a twist angle control point is provided at a specific distance from the leaf root.
[0011] A further improvement is made in step S5, where the adaptive control logic is as follows: when the wind speed is less than 5 m / s, the guide vane opens to a maximum opening angle of 15°; when the wind speed is greater than 10 m / s, the guide vane closes to an opening angle of less than 2°; and when the wind speed is between 5 and 10 m / s, the opening angle decreases linearly with the increase of wind speed.
[0012] A further improvement is that, in step S6, the composite structure design includes: S61. The blade body is made of alternating layers of E-glass fiber and epoxy resin at 0° / ±45° / 90°. S62, the tip region is reinforced with T700 carbon fiber, with the layup mainly in the 0° direction; S63, the leading edge region is reinforced with T300 carbon fiber, using 0° / 90° layup; S64. The leaf root area is covered with a mixture of glass fiber and basalt fiber. S65, the blade body is filled with PVC foam core material.
[0013] A blade for improving wind power generation efficiency, designed and manufactured using the method described above, includes: at least one blade root for connection to a wind turbine hub, a blade body disposed on the blade root, a guide vane disposed on the blade body for moving towards the blade body when the wind speed is greater than a predetermined value, a flow-dividing zone formed between the guide vane and the blade body, a drive mechanism disposed between the blade body and the guide vane for pushing the guide vane away from the blade body when the wind speed is less than a predetermined value and for guiding the guide vane towards the blade body when the wind speed is greater than a predetermined value, and a guide support disposed between the guide vane and the blade body for guiding the movement direction of the guide vane when the guide vane moves towards or away from the blade body.
[0014] A further improvement is that the drive mechanism includes a compression spring fixedly disposed between the blade body and the guide vane, which releases elastic potential energy to push the guide vane away from the blade body when the wind speed is less than a predetermined value, and compresses to generate elastic potential energy to allow the guide vane to move closer to the blade body when the wind speed is greater than a predetermined value.
[0015] A further improvement is that the blade body and the guide vane are respectively provided with two mounting slots for accommodating the compressed spring after contraction so that the guide vane is close to the leading edge of the blade body, and the two ends of the compression spring are respectively located in the two mounting slots.
[0016] A further improvement is that the guide support includes a fixing part fixedly disposed on the blade body, an arc-shaped plate disposed on the fixing part, an arc-shaped hole opened on the arc-shaped plate, and a guide shaft with one end fixedly disposed on the guide vane and the other end in clearance fit with the arc-shaped hole, which guides the movement direction of the guide vane when the guide vane moves closer to or away from the blade body.
[0017] The beneficial effects of this invention after adopting the above technical solution are as follows: In this application, through the design of the guide vane and the diversion zone formed between the guide vane and the blade body, when the wind speed is less than a predetermined value, the guide vane disperses the airflow, allowing some airflow to be guided to the upper surface of the blade body through the diversion zone. This increases the airflow velocity on the upper surface of the blade body. Compared with the airflow dispersion structure of traditional blade structures, increasing the airflow velocity on the upper surface of the blade body improves the starting force of the blade body, enabling the wind turbine blades to more effectively drive the wind turbine hub to rotate at low wind speeds, thereby improving power generation efficiency. Simultaneously, when the wind speed is greater than the predetermined value, the guide vane moves closer to the blade body under the action of the drive mechanism until it adheres to the leading edge of the blade body. At this point, the diversion zone closes and no longer guides airflow to the upper surface of the blade body, thereby reducing the starting force of the wind speed on the blade and preventing overload of the rotational speed that could affect the service life of the wind turbine.
[0018] Further effects: The deep integration of the biomimetic composite airfoil optimized by the genetic algorithm with the adaptive guide vane increases the maximum lift coefficient of the blade by more than 12% under low Reynolds number conditions and delays the stall angle of attack by about 5°, effectively expanding the high-efficiency operating range.
[0019] Further effects: The optimized blade root large twist angle, combined with the fully open guide vanes at low wind speeds, significantly improves the blade's starting torque and power generation capacity at a low inrush wind speed of 3 m / s.
[0020] Further benefits: By adopting a fiberglass-carbon fiber composite partitioned design, targeted enhancements are made to key parts (blade root, leading edge, and blade tip). While ensuring overall stiffness and fatigue life (≥20 years), multi-objective optimization keeps the blade weight and cost within a reasonable range (e.g., weight ≤850kg).
[0021] Further benefits: The provided design method organically combines aerodynamics, structure, and control optimization, and achieves global optimization through a multi-objective genetic algorithm, providing a complete and feasible optimization design process for small wind turbine blades with low Reynolds number.
[0022] Further benefits: By installing the slotted design, the spring can be fully retracted in the slot when the guide vane is completely attached to the blade body, which does not easily affect the gap between the guide vane and the blade body.
[0023] Further effects: Through the arc-shaped holes of the arc plate and the guide shaft fixed at one end to the guide vane, the movement trajectory of the guide vane can be guided as it moves closer to or away from the blade body. This allows the flow diversion zone to form a closed state each time the guide vane approaches the blade body, and also restricts the movement space of the guide vane, preventing the guide vane from moving too far away from the blade body. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 This is a schematic diagram of the blade structure in this invention; Figure 2 This is a schematic diagram of the structure of the blade body, guide vane, and guide support in this invention; Figure 3 This is a cross-sectional view of the blade body, guide vane, and drive mechanism in this invention; Figure 4 These are state diagrams of the guide vanes in this invention under different wind speed conditions; Figure 5 This is a schematic diagram of the airflow distribution on the blades in this invention.
[0026] Explanation of reference numerals in the attached drawings: 1. Blade root; 2. Blade body; 3. Guide vane; 4. Flow divider zone; 5. Compression spring; 6. Mounting slot; 7. Fixing part; 8. Arc plate; 9. Arc hole; 10. Guide shaft; 11. Blade tip. Detailed Implementation
[0027] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. Example 1
[0028] A blade design method for improving wind power generation efficiency is proposed, specifically for a 100kW small wind turbine generator set, to design high-efficiency blades under low Reynolds number operating conditions. The specific steps are as follows: Step S1, determine basic parameters: The suitable unit power is 100kW, and the design wind speed covers a low-wind-speed region with an annual average wind speed of 5-8 m / s. The number of blades is determined to be 3, the rated wind speed is 9 m / s, the cut-in wind speed is 3 m / s, and the safe wind speed is 40 m / s. The target Reynolds number is applicable within a range of 3 × 10⁻⁶ m / s. 5 Up to 8×10 5 The initial determination of the total blade length is 14.5m, in order to balance the wind-catching area and the tower load.
[0029] Step S2, Constructing a Biomimetic Composite Airfoil: Using the albatross wing airfoil as a prototype, construct a basic airfoil with a rounded leading edge and a thin, sharp trailing edge. Using XFOIL software, at a Reynolds number Re = 5 × 10⁻⁶... 5Aerodynamic analysis was performed on the airfoil, focusing on optimizing its maximum thickness location and camber distribution. Through iterative calculations, a composite airfoil was obtained that improved lift and drag by 18% compared to the original biomimetic airfoil, and delayed the stall angle of attack from 12° to 17°.
[0030] Step S3, Global Optimization using Multi-Objective Genetic Algorithm: In the optimization model, a multi-objective optimization model is established with "maximum lift coefficient improvement rate", "total blade mass" and "fatigue life" as objective functions and "manufacturing cost of a single blade ≤ 12,000 yuan" as constraint.
[0031] In the variable settings, 12 key parameters, such as the maximum thickness of the airfoil, camber, chord length distribution polynomial coefficient, twist control point angle, and tip carbon fiber layup ratio, were selected as optimization variables, and their physical boundaries were set (e.g., carbon fiber ratio ≤ 30%).
[0032] In algorithm execution, the NSGA-II algorithm was adopted, with a population size of 100, 50 generations, a crossover probability of 0.8, and a mutation probability of 0.05. Aerodynamic and structural finite element analysis was performed using MATLAB programming and ANSYS to achieve automatic iterative optimization. In the optimization results, after 50 generations of evolution, a set of Pareto optimal solutions were obtained. The solution that balances performance and cost was selected. This scheme controls the blade weight to 820 kg, predicts a 14.5% increase in the maximum lift coefficient, and achieves a fatigue life of 22 years.
[0033] Step S4, determine detailed geometric dimensions: Based on the optimization results, the final dimensions are determined as follows: blade root diameter 0.8m (matching the hub flange), blade tip diameter 0.12m. The chord length varies along the spanwise direction according to the formula: C(r) = 2.2 - 0.0012r³ (r is the distance from the blade root, unit: m). The twist angle linearly changes from 18° at the blade root to 2° at the blade tip.
[0034] Step S5: Design the adaptive guide vane: The guide vane covers the section of the blade from 1.5m from the blade root to the blade tip, with a total length of approximately 12m. The guide vane body adopts a composite structure of glass fiber and carbon fiber, and the hinge components are made of polytetrafluoroethylene. Its working principle is completely passive: when the wind speed is <5m / s, the low pressure difference on the upper surface causes it to open to 15°, guiding the airflow and increasing lift; when the wind speed is >10m / s, the high pressure difference on the lower surface causes it to close, maintaining the streamline shape; when the wind speed is 5-10m / s, the opening angle changes linearly between 8° and 12°.
[0035] Step S6, Detailed Design of the Composite Structure: The blade body (region 101) uses 24 layers of E-glass fiber / epoxy resin alternately laid at 0° / ±45° / 90°, with a total thickness of 12mm. The blade tip region (102, within 1.5m of the blade tip) is reinforced with 18 layers of T700 carbon fiber, mainly laid at 0° (60%), with a thickness of 9mm. The leading edge region (103, the leading edge within 0.3 times the chord length of the full span) uses 20 layers of T300 carbon fiber laid at 0° / 90°, with a thickness of 10mm, to resist wear. The blade root connection region (104, within 1.5m of the blade root) uses 30 layers of glass fiber and basalt fiber mixed layup, with a thickness of 15mm, to withstand huge torque. The internal cavity of the blade is filled with PVC foam core material with a density of 60kg / m³, which is replaced with high-density foam with a density of 80kg / m³ in stress concentration areas such as the blade root and blade tip.
[0036] Blade basic parameters and dimensions (I) Core performance parameters
[0037] (ii) Geometric Dimensions
[0038] (III) Material selection and layup
[0039] (iv) Adaptive airfoil design: Example 2
[0040] refer to Figures 1 to 5 As shown, this embodiment provides a blade designed and manufactured according to the method of Embodiment 1, comprising: at least one blade root 1 for connection to a wind turbine hub, a blade body 2 disposed on the blade root 1, a guide vane 3 disposed on the blade body 2 for moving towards the end of the blade body 2 when the wind speed is greater than a predetermined value, a flow-dividing zone 4 formed between the guide vane 3 and the blade body 2, a drive mechanism disposed between the blade body 2 and the guide vane 3 for pushing the guide vane 3 away from the end of the blade body 2 when the wind speed is less than a predetermined value and for moving the guide vane 3 towards the end of the blade body 2 when the wind speed is greater than a predetermined value, and a guide support member disposed between the guide vane 3 and the blade body 2 for guiding the movement direction of the guide vane 3 when the guide vane 3 moves towards or away from the end of the blade body 2. The blade tip 11 is located at the tail of the blade body 2, and the blade root 1 is located at the head of the blade body 2.
[0041] The part of the guide vane 3 near the leading edge of the blade body 2 is an arc-shaped part with the same shape as the leading edge of the blade body 2 after the guide vane 3 is close to the leading edge of the blade body 2, so that the flow diversion area 4 can be closed after the guide vane 3 is attached.
[0042] The predetermined wind speed values are divided into low wind speed (V<5m / s), medium wind speed (5–10m / s), and high wind speed (V>10m / s). When the wind speed is low, the compression spring 5 pushes the guide vane 3 away from the blade body 2. When the wind speed is medium, the guide vane 3 is closer to the blade body 2 and does not fit against the leading edge of the blade body 2. When the wind speed is high, the guide vane 3 fits tightly against the leading edge of the blade body 2.
[0043] The driving mechanism includes a compression spring 5 fixedly disposed between the blade body 2 and the guide vane 3. This spring releases elastic potential energy to push the guide vane 3 away from the blade body 2 when the wind speed is less than a predetermined value, and compresses to generate elastic potential energy to allow the guide vane 3 to move closer to the blade body 2 when the wind speed is greater than the predetermined value. The compression spring 5 adopts a coaxial nested double-stage spring design. The low-stiffness section spring is a cylindrical helical spring with a wire diameter of 6mm, a spring mean diameter of 30mm, 12 effective turns, a stiffness coefficient k=2.5N / mm, and a preload F0=60N. The high-stiffness section spring is a conical helical spring with a large end mean diameter of 28mm, a small end mean diameter of 15mm, a wire diameter of 5mm, and 8 effective turns. It is nested inside the low-stiffness spring, with a stiffness coefficient k=9N / mm and a trigger threshold F=200N (corresponding to the airflow pressure on the guide vane 3 at a wind speed V=10m / s). The spring material is 60Si2Mn, possessing good fatigue strength.
[0044] The blade body 2 and the guide vane 3 are respectively provided with two mounting slots 6 for accommodating the compressed spring 5 after contraction so that the guide vane 3 is close to the leading edge of the blade body 2. The two ends of the compression spring 5 are respectively located in the two mounting slots 6.
[0045] The depth of the slot 6 is set according to the overall length of the compressed spring 5 after compression, and needs to be set in advance based on the spring parameters.
[0046] The guide support includes a fixing part 7 fixedly disposed on the blade body 2, an arc-shaped plate 8 disposed on the fixing part 7, an arc-shaped hole 9 opened on the arc-shaped plate 8, and a guide shaft 10, one end of which is fixedly disposed on the guide vane 3 and the other end of which is clearance-fitted with the arc-shaped hole 9, for guiding the movement direction of the guide vane 3 when it moves closer to or away from the end of the guide vane 3 toward the blade body 2.
[0047] The fixing part 7 is fixedly installed on the blade body 2 by bolts or welding. One end of the guide shaft 10 is fixed to the guide vane 3 by fitting, welding, or snapping, while the other end passes through the arc-shaped hole 9 of the arc plate 8, achieving a sliding fit with the arc-shaped hole 9. During installation, the inner wall of the guide vane 3 needs to be pressed tightly against the leading edge of the blade body 2. Then, the arc plate 8 with the fixing part 7 is positioned so that its arc-shaped hole 9 is clearance-fitted with the other end of the guide shaft 10. The fixing part 7 is pressed down, and the movement trajectory of the guide vane 3 is tested to ensure that the guide vane 3 can achieve a tight fit between the two sides each time it approaches the blade body 2. After confirming the position, the fixing part 7 is fixed to the blade body 2, and the compression spring 5 is assembled and fixed in the two mounting slots. The stroke of the arc-shaped hole 9 is L=35mm, corresponding to the opening and closing angle range of the guide vane from 30° to 15°. The clearance between the guide shaft 10 and the arc-shaped hole 9 is 0.05-0.1mm, and grease lubrication can be used to reduce sliding resistance.
[0048] There are two options for the placement of the arc-shaped plates 8: For a single-piece guide vane, the thickness and rigidity of the arc-shaped plates 8 need to be increased, and two arc-shaped plates 8 are selected. The two arc-shaped plates 8 are located on the front and rear sides of the guide vane 3, and there are also two guide shafts 10. One end of each guide shaft 10 is fixed to the front and rear ends of the guide vane 3, and the arc-shaped plates 8 and guide shafts 10 work together to support the front and rear ends of the guide vane 3. When the guide vane 3 is divided into two, three (or four) arc-shaped plates 8 are selected, and guide shafts 10 are set at both the front and rear ends of each guide vane 3. When there are three arc-shaped plates 8, one arc-shaped plate 8 is fixed between the two guide vanes 3 (when the total number of arc-shaped plates 8 is four, two are set at this position), and the other two arc-shaped plates 8 are set at the front and rear ends.
[0049] The working principle of this invention is as follows: In this application, through the design of the guide vane 3 and the diversion zone 4 formed between the guide vane 3 and the blade body 2, when the wind speed is less than a predetermined value (low or medium wind speed), the guide vane 3 disperses the airflow, allowing a portion of the airflow to be guided to the upper surface of the blade body 2 through the diversion zone 4, thereby increasing the airflow velocity on the upper surface of the blade body 2. Compared with the airflow dispersion structure of traditional blade structures, by increasing the airflow velocity on the upper surface of the blade body 2, the starting force of the blade body 2 is improved, enabling the wind turbine blades to drive the wind turbine hub to rotate more effectively at low wind speeds, thereby improving power generation efficiency. Meanwhile, when the wind speed is greater than the predetermined value (high wind speed), the guide vane 3 is blown by the wind and moves closer to the blade body 2. After the airflow passes through the diversion zone 4 at high speed, the guide vane 3 is attracted and attached to the leading edge of the blade body 2. The compression spring 5 contracts and produces elastic deformation, thereby closing the diversion zone 4 and no longer guiding the airflow to the upper surface of the blade body 2. This reduces the starting force of the wind speed on the blade to prevent speed overload and affect the service life of the fan. By installing the slot 6, when the guide vane 3 is completely attached to the blade body 2, the spring can be fully retracted in the placement slot, which will not easily affect the gap between the guide vane 3 and the blade body 2. Through the arc-shaped hole 9 of the arc plate 8 and the guide shaft 10 fixed at one end to the guide vane 3, the movement trajectory of the guide vane 3 can be guided as it moves closer to or away from the blade body 2, so that the diversion zone 4 can be closed each time the guide vane 3 approaches the blade body 2. It can also limit the movement space of the guide vane 3 and prevent the guide vane 3 from moving too far away from the blade body 2.
[0050] This invention protects the structure of the product; the model numbers of the components are not protected by this invention and are common knowledge. Any component on the market that can achieve the functions described above can be used as a blade and design method to improve wind power generation efficiency. Therefore, the model numbers and other parameters of the components are not described in detail in this invention. The contribution of this invention lies in the scientific combination of the various components.
[0051] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions above are merely illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents. Any aspects not detailed in the present invention are well-known to those skilled in the art.
Claims
1. A blade design method for improving wind power generation efficiency, characterized in that, Includes the following steps: S1. Determine the basic design parameters of the blade body: Based on the target unit power, rated wind speed, cut-in wind speed and low Reynolds number operating range, determine the number of blade bodies and the total length of the blade body; S2. Construct a biomimetic composite airfoil library: Using the albatross wing airfoil as a biomimetic prototype, determine the geometric characteristic parameters of the airfoil, and optimize the basic biomimetic airfoil at the target Reynolds number based on aerodynamic analysis software to form a composite airfoil with improved lift-to-drag ratio. S3. Global optimization of main leaf parameters based on multi-objective genetic algorithm: S31. Set optimization objectives with the core objectives of maximizing the lift coefficient, minimizing the total weight of the blade body, and maximizing fatigue life, while also constraining manufacturing costs. S32. Set the geometric parameters of the composite airfoil, the spanwise chord length and twist angle distribution parameters of the blade body, and the composite material layup ratio as optimization variables; S33. The NSGA-II genetic algorithm is used in conjunction with aerodynamic and structural simulation software to perform joint simulation optimization and obtain the optimal parameter combination. S4. Determine the geometric configuration of the blade body: Based on the optimal parameter combination obtained in step S3, determine the detailed chord length distribution and twist angle distribution of the blade body; S5. Design of adaptive passive guide vane: A guide vane is set at the leading edge of the blade body, and its hinge position and adaptive control logic are determined. The control logic enables the guide vane opening angle to be automatically adjusted with the wind speed. S6. Conduct composite structure design: For different functional areas of the blade body, design layup schemes using glass fiber, carbon fiber or their hybrid materials, and fill the blade body with core material.
2. The blade design method for improving wind power generation efficiency according to claim 1, characterized in that: In step S1, the target unit power is 100kW, and the low Reynolds number operating range is Re=3×10. 5 - 8×10 5 The number of blade bodies is 3, and the total length of the blade bodies is 14.5m.
3. The blade design method for improving wind power generation efficiency according to claim 1, characterized in that: In step S2, the leading edge radius of the biomimetic prototype airfoil is 0.08 times the local chord length, the trailing edge thickness is 0.02 times the local chord length, and the maximum thickness is located at 25%-30% of the chord length.
4. The blade design method for improving wind power generation efficiency according to claim 1, characterized in that: In step S3, the optimization variables specifically include: the maximum thickness of the airfoil, the camber, the cubic polynomial coefficients of the chord length along the span, the twist gradient distribution parameters from the blade root to the blade tip, and the carbon fiber layup ratio in the blade tip region.
5. The blade design method for improving wind power generation efficiency according to claim 1, characterized in that: In step S4, the chord length distribution satisfies the following: the chord length at the leaf root is 2.2m, the chord length at the leaf tip is 0.35m, and the chord length in the middle region gradually changes according to a cubic polynomial; the twist angle distribution satisfies the following: the twist angle at the leaf root is 18°, the twist angle at the leaf tip is 2°, the twist angle in the middle gradually changes according to a linear formula, and a twist angle control point is provided at a specific distance from the leaf root.
6. The blade design method for improving wind power generation efficiency according to claim 1, characterized in that: In step S5, the adaptive control logic is as follows: when the wind speed is less than 5 m / s, the guide vane opens to a maximum opening angle of 15°; when the wind speed is greater than 10 m / s, the guide vane closes to an opening angle of less than 2°; when the wind speed is between 5 and 10 m / s, the opening angle decreases linearly with the increase of wind speed.
7. The blade design method for improving wind power generation efficiency according to claim 1, characterized in that: In step S6, the composite structure design includes: S61. The blade body is made of alternating layers of E-glass fiber and epoxy resin at 0° / ±45° / 90°. S62, the tip region is reinforced with T700 carbon fiber, with the layup mainly in the 0° direction; S63, the leading edge region is reinforced with T300 carbon fiber, using 0° / 90° layup; S64. The leaf root area is covered with a mixture of glass fiber and basalt fiber. S65, the blade body is filled with PVC foam core material.
8. A blade for improving wind power generation efficiency, characterized in that: Designed and manufactured using the method described in any one of claims 1-7, the product comprises: at least one blade root for connection to a wind turbine hub, a blade body disposed on the blade root, a guide vane disposed on the blade body for moving towards the blade body end when the wind speed is greater than a predetermined value, a flow splitting zone formed between the guide vane and the blade body, a drive mechanism disposed between the blade body and the guide vane for pushing the guide vane away from the blade body end when the wind speed is less than a predetermined value and for allowing the guide vane to move towards the blade body end when the wind speed is greater than a predetermined value, and a guide support disposed between the guide vane and the blade body for guiding the movement direction of the guide vane when the guide vane moves towards or away from the blade body end.
9. A blade for improving wind power generation efficiency according to claim 8, characterized in that: The drive mechanism includes a compression spring fixedly disposed between the blade body and the guide vane, which releases elastic potential energy to push the guide vane away from the blade body when the wind speed is less than a predetermined value, and compresses to generate elastic potential energy to allow the guide vane to move closer to the blade body when the wind speed is greater than a predetermined value.
10. A blade for improving wind power generation efficiency according to claim 9, characterized in that: The blade body and the guide vane are respectively provided with two mounting slots for accommodating the compressed spring after contraction so that the guide vane is close to the leading edge of the blade body. The two ends of the compression spring are respectively located in the two mounting slots.