Wind driven generator blade and horizontal-axis wind driven generator

Abstract

The utility model relates to a wind driven generator blade and a horizontal-axis wind driven generator, and belongs to the technical field of wind driven generators. A flexible trailing edge system is arranged at the trailing edge end of a blade main body and comprises a first flexible film, a suction surface trailing edge sheet-shaped piece and a pressure surface trailing edge sheet-shaped piece; the suction surface tail edge sheet-shaped piece and the pressure surface tail edge sheet-shaped piece are provided with free ends which are arranged in an overhanging mode relative to the rear edge end face of the blade body, and the free ends of the suction surface tail edge sheet-shaped piece and the pressure surface tail edge sheet-shaped piece are connected in a sealed mode through a first flexible film. According to the wind driven generator, the lift coefficient can be increased, stall is delayed, wide-working-condition operation of the wind driven generator is achieved, the wind driven generator is suitable for wind energy capture in a larger range, low-wind-speed wind energy utilization is improved, the performance requirement for materials can be reduced, and the wind driven generator has better stability when being applied to a field wind field and is more suitable for industrial application.

Description

Technical Field

[0001] This utility model relates to a wind turbine blade and a horizontal axis wind turbine, belonging to the field of wind turbine technology. Background Technology

[0002] my country is currently at a critical stage of energy transition, and "building a clean, low-carbon, safe, and efficient modern energy system" is a key goal of my country's energy development. It is projected that by 2050, my country's energy development will achieve "two 50% targets": non-fossil energy will account for over 50% of primary energy consumption, and electricity will account for over 50% of final energy consumption. Wind power, as an excellent renewable green energy source, plays a crucial role in achieving these strategic energy goals. After years of development, wind power has become an increasingly important part of the clean energy power system, with a significantly larger installed capacity. According to data released by the National Energy Administration, as of the end of December 2023, wind power installed capacity reached approximately 440 million kilowatts, generating approximately 810 billion kilowatt-hours of electricity, becoming a major force in China's clean energy substitution.

[0003] The wind power industry has developed rapidly in recent years, mainly due to technological advancements in the size and capacity of wind turbine generators. By 2023, wind turbines with a single unit capacity of 16 MW had rolled off the production line, with individual blade lengths exceeding 143 meters, and unit costs below 1200 yuan / kW. However, while bringing about the industry's booming development, the obvious technological drawbacks and limitations of ultra-large size have gradually become apparent. Firstly, the vibration, fatigue resistance, and reliability-related indicators of ultra-large blades have significantly decreased. Secondly, the production, transportation, and installation conditions for these large components are becoming increasingly demanding, posing significant risks to the safe operation of wind turbines. Therefore, improving the wind energy capture efficiency of wind turbines with a reasonable structure is the key to the development of the wind power industry, which will undoubtedly propel the industry to a new level and bring extremely high economic and social benefits.

[0004] Large wind turbines rely on their blades to capture wind energy. Improving capture efficiency is primarily achieved through swept area (tip speed ratio), yaw adjustment, pitch angle adjustment, and blade airfoil design. Increasing the swept area, i.e., increasing the blade geometry, has revealed numerous problems and bottlenecks. As for yaw adjustment and pitch angle adjustment, due to the structural size and weight of large wind turbines, the movement of the turbine head and blades cannot be agilely, quickly, and precisely matched to changes in the flow field, and current technology offers limited potential for further development. Airfoil design remains the core of aerodynamics. From borrowing from aircraft airfoils to developing proprietary airfoils for wind turbine blades, many excellent airfoils have emerged. However, engineering practice shows that simple modifications to the aerodynamic shape alone are unlikely to significantly improve efficiency in complex environments. These problems mainly stem from the extremely high uncertainty and non-uniformity of the wind fields where wind turbines actually operate. Wind speed and direction constantly change with significant amplitude, especially in complex terrain (such as protruding plateaus, small slopes, hills, mountains, and ridges), where the flow field exhibits stronger specificity, greater turbulence, and particularly pronounced unsteady characteristics. Faced with constantly changing wind fields, wind turbines struggle to operate within their design operating range. Especially when effective wind speeds decrease, flow separation easily occurs on the blades, leading to reduced lift and torque, increased drag, and ultimately, inefficient operation. While numerous flow control technologies have been developed in aerodynamics to suppress or delay flow separation and improve airfoil lift coefficients and lift-to-drag ratios—such as plasma flow control and various flap technologies used in aircraft—the unique requirements of wind turbine blades (e.g., lightning protection, passive operation) preclude complex active structures, limiting them to simple passive methods. Currently, the main technologies employed on blades to improve wind energy capture efficiency include: vortex generators, spoilers, Gurney flaps, and fixed aerodynamic accessories such as tip winglets.

[0005] Currently, once the airfoil design is finalized, its lift-drag characteristics are fixed, achieving optimal performance under the design conditions while balancing other operating conditions. Vortex generators, spoilers, and Gurney flaps are also fixed, improving the efficiency of the original airfoil under the design conditions, but with limited effect under other complex conditions. From an engineering practice perspective, the airfoil can capture approximately 50% of the aerodynamic energy under the design conditions, while other individual improvements in power generation increase approximately 0.5-1%, and no more than 3% after system implementation. Their biggest problem is their fixed nature; they cannot adjust to complex and variable flow fields, easily leading to flow separation and stall, failing to capture more energy. In terms of lift-drag characteristics, they cannot simultaneously achieve a low lift coefficient or a small stall angle of attack, resulting in a narrow effective operating range. Furthermore, due to limitations in production, manufacturing, transportation, and installation processes, it is impossible to maintain the designed airfoil shape, especially achieving a sharp trailing edge with a specific curve, which also leads to a decrease in the actual airfoil's wind energy capture efficiency compared to the design airfoil.

[0006] Furthermore, patent document CN106351799A discloses a horizontal axis wind turbine, including a generator, a gearbox, and a wind turbine. The wind turbine includes several blades and a horizontally mounted shaft, with the blades circumferentially spaced on the shaft. Each blade has at least one cavity, and the opening of the cavity is covered with a flexible membrane. This solution uses partially flexible blades, which improves the lift-to-drag ratio of the wind turbine blades, increases the output torque of the wind turbine, and broadens the effective operating range of the wind turbine blades. It enables effective utilization of wind energy at low wind speeds and has a simple structure that is easy to control. However, the following problems have been found in practical applications of this solution:

[0007] (1) The leading edge of the blade is particularly sensitive to changes in aerodynamic shape. If it adapts to the flow field characteristics, the effect is obvious. However, if the structural material parameters are not suitable, the opposite effect will occur. It is highly selective for the structure and materials attached to it.

[0008] (2) Whether it is the leading edge or the trailing edge of the blade, the performance requirements of the functional film are extremely high. It should be thin, low density, good dimensional stability, non-creep, fatigue-resistant, tear-resistant, wear-resistant, and highly reliable. This requires new development and is quite difficult. Other materials are used as substitutes, and the functional effect is extremely unstable. Utility Model Content

[0009] The technical problem to be solved by this utility model is to provide a wind turbine blade that can not only improve the lift coefficient, delay stall, enable the wind turbine to operate under a wide range of conditions, adapt to a wider range of effective wind speed energy capture, and improve the utilization of low wind speed wind energy, but also reduce the performance requirements of materials, have better stability when applied to field wind farms, and be more suitable for industrial applications.

[0010] The technical solution adopted by this utility model to solve its technical problem is as follows: a wind turbine blade, including a blade body, one side surface of the blade body being the blade suction surface and the other side surface being the blade pressure surface, a flexible trailing edge system being provided at the trailing edge end of the blade body, the flexible trailing edge system including a first flexible membrane, a suction surface trailing edge sheet, and a pressure surface trailing edge sheet; the suction surface trailing edge sheet is correspondingly and fixedly disposed at the trailing edge end of the blade suction surface, and the suction surface trailing edge sheet has a free end extending away from the trailing edge end of the blade body relative to the trailing edge end of the blade body; the pressure surface trailing edge sheet is correspondingly and fixedly disposed at the trailing edge end of the blade pressure surface, and the pressure surface trailing edge sheet has... The blade has a free end that extends away from the trailing edge of the blade body. The suction surface trailing edge plate and the pressure surface trailing edge plate are arranged opposite each other. The overhang length of the free end of the suction surface trailing edge plate relative to the trailing edge of the blade body is greater than the overhang length of the free end of the pressure surface trailing edge plate relative to the trailing edge of the blade body. The free ends of the suction surface trailing edge plate and the pressure surface trailing edge plate are connected by a first flexible membrane to form a closed connection, so that the suction surface trailing edge plate, the pressure surface trailing edge plate and the first flexible membrane enclose the trailing edge of the blade body to form a channel structure whose axial direction is consistent with the length direction of the trailing edge of the blade body.

[0011] The beneficial effects of the above scheme are as follows: When the wind turbine blade is working, air moves from the leading edge to the trailing edge. Under the combined action of complex aerodynamic forces and blade rotation, the entire flexible trailing edge system will move accordingly. The trailing edge plate of the suction surface is the main moving part of the entire structure, mainly oscillating. When the wind speed is relatively high, no flow separation occurs on the suction surface of the blade, and the dynamic and static pressure changes on the trailing edge plate of the suction surface are not significant. Therefore, its oscillation amplitude towards the pressure surface of the blade is relatively small, and the equivalent airfoil camber change is not significant. When the wind speed decreases, flow separation occurs on the suction surface of the blade, forming separation vortices. The dynamic and static pressure changes on the trailing edge plate of the suction surface increase, leading to a larger oscillation amplitude towards the pressure surface of the blade. This results in a larger equivalent airfoil camber, changing the dynamic and static pressure distribution around the airfoil, thereby reducing separation vortices, improving the flow field morphology, and showing an increase in the airfoil lift coefficient. When wind load is excessive, the flexible trailing edge system experiences increased stress, causing the suction surface trailing edge plate to tilt upwards, resulting in a disadvantageous aerodynamic shape. This leads to a significant decrease in lift and a substantial increase in drag. Furthermore, its flexible vibration helps to dissipate excessive wind load, protecting the blades and wind turbine from the risks associated with excessive load. The above working principle indicates that the main mechanism of the flexible trailing edge system in this invention is to improve the flow field morphology by adaptively changing the equivalent airfoil camber, preventing or reducing separation vortices, broadening the operating conditions, and enhancing the blades' ability to capture wind energy, thereby improving the wind turbine's power generation efficiency. This invention does not require consideration of separation points; it is based on the adaptive change of camber by the suction surface trailing edge plate. Once the camber changes, the lift coefficient changes accordingly, demonstrating strong adaptability. The core component is the suction surface trailing edge plate. Due to its greater material rigidity and thickness compared to the flexible membrane in traditional solutions, it is generally less prone to self-excitation in the airflow field, greatly improving the reliability and durability of the materials and structure. In this invention, the suction-side trailing edge plate forms a cantilever beam structure relative to the trailing edge of the blade. The thickness of the suction-side trailing edge plate is typically only 1 / 5 to 1 / 10 of the average thickness of the original trailing edge, making it closer to the theoretically ideal pointed trailing edge in terms of airfoil shape, further improving lift and reducing drag. The suction-side trailing edge plate, the pressure-side trailing edge plate, and the first flexible membrane enclose each other at the trailing edge of the blade body to form a channel structure whose axial direction is consistent with the length direction of the trailing edge of the blade body. This channel can carry water and air. During blade operation, under the combined action of Coriolis force and aerodynamic force, high-speed gas blown towards the blade tip will appear inside the flexible trailing edge system and be blown out at the trailing edge near the blade tip, which can effectively improve the flow field near the blade tip and is beneficial to increasing blade torque. Furthermore, with the above-mentioned specific structural form, no new materials need to be developed for the suction-side trailing edge plate, the pressure-side trailing edge plate, and the first flexible membrane. Only general engineering requirements such as fatigue resistance, wear resistance, and high reliability are required, and existing materials can achieve good results.

[0012] To ensure a simple and reliable structure, and to facilitate the overall processing and assembly, in some preferred embodiments, the end of the suction surface trailing edge plate near the blade body is attached to and fixed to the suction surface of the blade; the end of the pressure surface trailing edge plate near the blade body is attached to and fixed to the pressure surface of the blade. For better overall performance, the specific preferred parameters in this embodiment are as follows: the overhang length of the free end of the suction surface trailing edge plate relative to the trailing edge of the blade body is set to L3, and the overhang length of the free end of the pressure surface trailing edge plate relative to the trailing edge of the blade body is set to L4. L4 is between 1 / 2 and 2 / 3 of the value of L3; the value of L3 ranges from 10% to 20% of the chordal length of the blade body.

[0013] To further facilitate processing and assembly, a preferred embodiment of the above scheme is that a connecting frame is fixedly attached to the suction surface of the blade. The connecting frame is located on the side of the suction surface trailing edge sheet near the leading edge of the blade body. The side end face of the connecting frame and the side end face of the suction surface trailing edge sheet are fixedly connected as a whole by an elastic mounting component. The elastic mounting component is also fixedly connected to the blade suction surface. Since the blade surface processing may be uneven, using an elastic mounting component to assemble the suction surface trailing edge sheet and the connecting frame allows the outer surfaces of the suction surface trailing edge sheet, the elastic mounting component, and the connecting frame facing away from the blade suction surface to form a relatively flatter processing surface. In the preferred embodiment of setting a second flexible membrane, this also helps ensure the flatness of the coating.

[0014] To further enhance the coupling strength between the flexible trailing edge system and the flow field, increase its sensitivity to separation vortices, and improve the lift coefficient under small angle-of-attack conditions, a further preferred embodiment is that the suction surface trailing edge plate, the elastic mounting component, and an outer surface of the connecting frame facing away from the blade suction surface constitute the process mounting surface of the integral structure. A second flexible membrane is attached to the process mounting surface, with its circumferential edge sealed and fixedly connected to the process mounting surface. Due to its light weight and large area, the second flexible membrane easily couples with the flow field, thereby transferring energy to the suction surface trailing edge plate, strengthening the coupling between the flexible trailing edge system and the flow field, and improving its adaptive performance to changes in the flow field.

[0015] To ensure a simple and reliable structure, and to facilitate the processing and assembly of the overall structure, in some other preferred embodiments, the end of the suction surface trailing edge piece near the blade body and the end of the pressure surface trailing edge piece near the blade body are fixedly and closedly connected by a connecting plate. The suction surface trailing edge piece, the pressure surface trailing edge piece, and the connecting plate are integrally formed into a U-shaped structural component. The outer end face of the U-shaped structural component near the blade body is attached to and fixedly connected to the trailing edge end face of the blade body.

[0016] To further facilitate processing and assembly, a preferred embodiment of the above solution is that the outer end face of the U-shaped structural component near the blade body has an outward extension relative to the trailing edge end face of the blade body on the side near the blade suction surface to form a first positioning mounting surface. A connecting frame is fixedly attached to the blade suction surface. The connecting frame is located on the side of the trailing edge plate of the suction surface near the leading edge of the blade body. The side end face of the connecting frame and the first positioning mounting surface are fixedly connected as a whole by an elastic mounting member. The elastic mounting member is fixedly connected to the blade suction surface.

[0017] To further improve the coupling strength between the flexible trailing edge system and the flow field, enhance its sensitivity to separation vortices, and improve the lift coefficient under small angle of attack conditions, a further preferred embodiment of the above scheme is that the suction surface trailing edge plate, the elastic mounting component, and the outer surface of the connecting frame facing away from the blade suction surface are combined to form a process mounting surface of the overall structure. A second flexible membrane is attached to the process mounting surface, and the circumferential edge of the second flexible membrane is sealed and fixedly connected to the process mounting surface.

[0018] To further facilitate processing and assembly, and improve overall performance, a further preferred embodiment of the above scheme is that the trailing edge of the blade body has a first positioning and mounting groove, the two ends of which intersect with the blade suction surface and the blade pressure surface, respectively. The bottom wall of the first positioning and mounting groove is a second positioning and mounting surface, which is the trailing edge end face of the blade body used to connect with the outer end face of the U-shaped structure near the blade body. The two side end faces of the U-shaped structure corresponding to the blade body spanwise have corresponding fitting gaps with respect to the two inner side walls of the first positioning and mounting groove. The free end face of the suction surface trailing edge plate is flush with or outside the outer end face of the first positioning and mounting groove. The blade suction surface has a second positioning and mounting groove on the side of the first positioning and mounting groove near the leading edge of the blade body. The end of the second positioning and mounting groove near the U-shaped structure intersects with the second positioning and mounting surface. The elastic mounting component and the connecting frame are both fixed in the second positioning and mounting groove.

[0019] To achieve relatively better overall performance, the specific preferred settings of the above scheme are as follows: the overhang length of the free end of the suction surface trailing edge plate relative to the connecting plate is set to L5, and the overhang length of the free end of the pressure surface trailing edge plate relative to the connecting plate is set to L6, with L6 being 1 / 2 to 2 / 3 of the value of L5; the overhang length of the free end of the suction surface trailing edge plate relative to the outer end face of the first positioning mounting groove is not greater than 20% of the chordal length of the blade body.

[0020] To enhance structural reliability, a further preferred embodiment of the above scheme involves fixing a water-resistant corrosion-resistant component to the inner wall of the channel structure at the trailing edge of the blade body. This component is positioned on the side of the channel structure near the leading edge of the blade body and extends axially along the channel structure. The water-resistant corrosion-resistant component primarily absorbs the impact flow energy of water droplets or water flow passing through the flexible trailing edge system, thus better protecting the structure from damage.

[0021] To enhance structural reliability, a further preferred embodiment of the above scheme involves fixing an elastic limiting component to the inner wall of the channel structure at the trailing edge of the blade body. This elastic limiting component is connected to the trailing edge plate of the pressure surface and extends axially along the channel structure. The primary function of the elastic limiting component is to utilize its material elasticity to restrict the swing or deformation amplitude of the trailing edge plate of the suction surface. Within normal wind load ranges, excessively vigorous movement or extreme deformation of the trailing edge plate of the suction surface can exacerbate the deterioration of the flow field, leading to a decrease in lift and an increase in drag. Therefore, the elastic limiting component is used to limit the movement amplitude of the trailing edge plate of the suction surface, ensuring that its swing angle does not exceed the designed maximum swing angle θ2. This also protects the structural materials from damage and improves the reliability and durability of the flexible trailing edge system.

[0022] To make the structure simple and reliable, and easy to process and assemble, a further preferred embodiment of the above solution is that the first end of the first flexible membrane is attached to and fixedly connected to the free end of the suction surface tail edge sheet facing the pressure surface tail edge sheet, and the second end of the first flexible membrane is attached to and fixedly connected to the free end of the pressure surface tail edge sheet facing away from the suction surface tail edge sheet.

[0023] To help eliminate aerodynamic noise, a further preferred embodiment of the above scheme is that the free end face of the suction surface trailing edge plate is a toothed surface, and the protrusions and grooves of the toothed surface are alternately arranged along the length of the trailing edge of the blade body.

[0024] To achieve relatively better overall performance, some other preferred parameters in the above scheme are as follows: one end of the blade body in the spanwise direction is the blade root end, and the other end is the blade tip end. The spanwise length of the blade body is set as L1. The starting point of the flexible trailing edge system arrangement area on the trailing edge end face of the blade body is set as point A, and the ending point is set as point B. The flexible trailing edge system is arranged continuously or intermittently in the area between point A and point B. The distance between point A and point B in the spanwise direction of the blade body is set as L2, and L2 is 20% to 70% of L1. Point A is closer to the blade tip than point B. The distance between point A and the blade tip in the spanwise direction of the blade body is not less than 10% of L1, and the distance between point B and the blade root end in the spanwise direction of the blade body is not less than 20% of L1.

[0025] The wind turbine blades of this utility model generally include at least the following steps in their specific manufacturing process:

[0026] Step 1: The blade body and flexible trailing edge system are pre-processed separately;

[0027] Step 2: Assemble the blade body and flexible trailing edge system at the wind turbine installation site. When connecting the free end of the fixed pressure surface trailing edge plate and the first flexible membrane, control the relative position of the first flexible membrane and the pressure surface trailing edge plate so that the free end of the suction surface trailing edge plate has a preset initial installation angle θ1 relative to the blade pressure surface.

[0028] In the preferred embodiment, the initial installation angle θ1 of the free end of the suction surface trailing edge plate in step two is set as follows: the proportion of wind frequency below half the rated wind speed of the wind turbine generator is set as M. The value of θ1 is adjusted linearly within the range of 0 to 30° based on the value of M. If the value of M is 100%, then the value of θ1 is 30°; if the value of M is 0, then the value of θ1 is 0°. The variation of this initial installation angle θ1 directly affects the important camber parameter of the blade airfoil. The larger the initial installation angle θ1, the greater the camber of the blade airfoil, and the greater the maximum lift coefficient of the blade airfoil. The flexible trailing edge system in this invention can specifically adjust the initial installation angle θ1 according to the on-site wind environment, which adjusts an important parameter of the blade airfoil, "camber," thereby balancing and optimizing the lift and drag coefficients and improving power generation efficiency.

[0029] Based on the aforementioned wind turbine blades, this utility model also provides a horizontal axis wind turbine, including a generator, a gearbox, and a wind turbine. The wind turbine includes several blades and a horizontally mounted shaft. The blades are mounted at equal intervals along the circumference of the shaft. The blades used are the wind turbine blades with flexible trailing edge systems described above. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a first embodiment of the flexible trailing edge system in this utility model (corresponding to the chordal section of the blade body);

[0031] Figure 2 for Figure 1 The illustrated embodiment is a partial structural diagram of the blade's trailing edge (corresponding to the tangential section of the blade body);

[0032] Figure 3 for Figure 2 The embodiment shown is a schematic diagram of the overall structure in the tangential section of the blade body;

[0033] Figure 4This is a schematic diagram of the structure of Embodiment 2 of the flexible trailing edge system in this utility model (corresponding to the chordal section of the blade body);

[0034] Figure 5 for Figure 4 The illustrated embodiment is a partial structural diagram of the blade's trailing edge (corresponding to the tangential section of the blade body);

[0035] Figure 6 for Figure 5 The embodiment shown is a schematic diagram of the overall structure in the tangential section of the blade body;

[0036] Figure 7 for Figure 5 A three-dimensional structural diagram of the wind turbine blade corresponding to the embodiment shown (only the blade tip is shown);

[0037] Figure 8 for Figure 7 The illustrated embodiment is a three-dimensional structural diagram showing the blade body and flexible trailing edge system in a separated state;

[0038] Figure 9 This is a schematic diagram of the distribution method of the flexible trailing edge system in this utility model;

[0039] Figure 10 This is a schematic diagram of the second distribution method of the flexible trailing edge system in this utility model;

[0040] Figure 11 This is a schematic diagram of the third distribution method of the flexible trailing edge system in this utility model;

[0041] Figure 12 This is a three-dimensional structural diagram of the suction surface tail edge plate-like member according to one embodiment of the present utility model;

[0042] Figure 13 This is a schematic diagram illustrating the working principle of this utility model. Figure 1 ;

[0043] Figure 14 This is a schematic diagram illustrating the working principle of this utility model. Figure 2 ;

[0044] Figure 15 This is a schematic diagram illustrating the working principle of this utility model. Figure 3 ;

[0045] Figure 16 This is a comparison diagram showing the effect of the embodiments of this utility model on the lift coefficient compared with the existing conventional technology;

[0046] Figure 17 This is a comparison chart showing the effect of the embodiments of this utility model on the drag coefficient compared to existing conventional technologies.

[0047] The components in the figure are labeled as follows: blade body 10, blade suction surface 11, blade pressure surface 12, first positioning mounting groove 13, second positioning mounting surface 14, second positioning mounting groove 15, blade root end 16, blade tip 17, flexible trailing edge system 20, suction surface trailing edge sheet 21, pressure surface trailing edge sheet 22, first flexible membrane 23, connecting frame 24, elastic mounting component 25, second flexible membrane 26, connecting plate 27, first positioning mounting surface 28, anti-corrosion component 29, elastic limiting component 210, toothed surface 211. Detailed Implementation

[0048] The present invention will be further described below with reference to the accompanying drawings.

[0049] like Figures 1 to 8 As shown, the wind turbine blade of this utility model includes a blade body 10. One side surface of the blade body 10 is a blade suction surface 11, and the other side surface is a blade pressure surface 12. A flexible trailing edge system 20 is provided at the trailing edge end of the blade body 10. The flexible trailing edge system 20 includes a first flexible membrane 23, a suction surface trailing edge sheet 21, and a pressure surface trailing edge sheet 22. The suction surface trailing edge sheet 21 is fixedly disposed at the trailing edge end of the blade suction surface 11, and has a free end extending away from the trailing edge end of the blade body 10. The pressure surface trailing edge sheet 22 is fixedly disposed at the trailing edge end of the blade pressure surface 12, and has a free end extending away from the trailing edge end of the blade body 10. The trailing edge of the blade body 10 has a free end extending away from the blade body 10; the suction surface trailing edge plate 21 and the pressure surface trailing edge plate 22 are arranged opposite to each other, and the overhang length of the free end of the suction surface trailing edge plate 21 relative to the trailing edge of the blade body 10 is greater than the overhang length of the free end of the pressure surface trailing edge plate 22 relative to the trailing edge of the blade body 10; the free ends of the suction surface trailing edge plate 21 and the pressure surface trailing edge plate 22 are connected by a first flexible membrane 23 to form a closed connection, so that the suction surface trailing edge plate 21, the pressure surface trailing edge plate 22 and the first flexible membrane 23 enclose the trailing edge of the blade body 10 to form a channel structure whose axial direction is consistent with the length direction of the trailing edge of the blade body 10. The phrase "the suction surface tail edge plate 21 and the pressure surface tail edge plate 22 are arranged opposite each other" should be interpreted broadly. They do not have to be parallel, as long as there is a certain gap to facilitate the free end of the suction surface tail edge plate 21 to swing.

[0050] More specifically, the suction surface tail edge sheet 21 and the pressure surface tail edge sheet 22 can generally be non-metallic thin plate or sheet structures with a certain strength. The first flexible membrane 23 is a polymer flexible membrane material. There is no need to develop new materials for the suction surface tail edge sheet 21, the pressure surface tail edge sheet 22 and the first flexible membrane 23. They are just general engineering requirements for fatigue resistance, wear resistance and high reliability. Existing materials can achieve good results. Those skilled in the art can make reasonable selections according to the actual situation.

[0051] In some embodiments, the suction surface trailing edge piece 21 and the pressure surface trailing edge piece 22 can be integrally manufactured with the blade body 10. However, from an engineering practical perspective, the suction surface trailing edge piece 21 and the pressure surface trailing edge piece 22 are mainly used as structural units. For specific fixing, they are generally installed onto the corresponding mounting surface using adhesive bonding. The two ends of the first flexible membrane 23 are also generally connected and fixed using adhesive bonding. Of course, in some alternative embodiments, bolt connections, riveting, or other fixing methods can be used instead, and adhesive bonding, bolt connections, riveting, and other fixing methods can be combined arbitrarily.

[0052] For preferred implementation methods of modifying the trailing edge of conventional blades, please refer to [reference needed]. Figures 1 to 3 In some preferred embodiments, the end of the suction surface trailing edge plate 21 near the blade body 10 can be attached to and fixedly connected to the blade suction surface 11; the end of the pressure surface trailing edge plate 22 near the blade body 10 can be attached to and fixedly connected to the blade pressure surface 12. To achieve relatively better overall performance, the specific preferred parameters in this embodiment are as follows: the overhang length of the free end of the suction surface trailing edge plate 21 relative to the trailing edge of the blade body 10 is set to L3, and the overhang length of the free end of the pressure surface trailing edge plate 22 relative to the trailing edge of the blade body 10 is set to L4. The value of L4 is 1 / 2 to 2 / 3 of the value of L3; the value of L3 ranges from 10% to 20% of the chordal length of the blade body 10. Of course, the above solution can also be applied to newly manufactured wind turbine blades. In some embodiments, for newly manufactured wind turbine blades, the blade body 10 can also provide corresponding positioning and mounting grooves on the blade suction surface 11 and the blade pressure surface 12, respectively, corresponding to the fixed ends of the suction surface trailing edge piece 21 and the pressure surface trailing edge piece 22, so that the suction surface trailing edge piece 21 and the pressure surface trailing edge piece 22 can be more smoothly connected with the blade suction surface 11 and the blade pressure surface 12.

[0053] In some preferred embodiments, a connecting frame 24 is fixedly attached to the suction surface 11 of the blade. The connecting frame 24 is located on the side of the trailing edge sheet 21 of the suction surface near the leading edge of the blade body 10. The side end face of the connecting frame 24 and the side end face of the trailing edge sheet 21 of the suction surface are fixedly connected as a whole by an elastic mounting member 25. The elastic mounting member 25 is fixedly connected to the suction surface 11 of the blade. The blade surface processing may have unevenness. Using the elastic mounting member 25 to assemble the trailing edge sheet 21 of the suction surface and the connecting frame 24 allows the outer surface of the trailing edge sheet 21 of the suction surface, the elastic mounting member 25, and the connecting frame 24 facing away from the suction surface 11 of the blade to form a relatively flat process surface. In the preferred embodiment of setting the second flexible film, it is also beneficial to ensure the flatness of the coating. The connecting frame 24 can generally adopt a rectangular frame-type thin plate structure with a hollow internal structure to avoid uneven mounting surfaces. The connecting frame 24 can generally be made of the same material as the suction surface tail edge plate 21, and the elastic mounting part 25 is generally made of easily deformable elastic non-metallic material. The installation and fixing of the connecting frame 24 and the elastic mounting part 25 are also conventional techniques, which can be adhesive bonding, bolt connection, or riveting, or any combination of adhesive bonding, bolt connection, riveting and other fixing methods can be used.

[0054] To further enhance the coupling strength between the flexible trailing edge system 20 and the flow field, improve its sensitivity to separation vortices, and enhance the lift coefficient under small angle-of-attack conditions, in some preferred embodiments, the suction surface trailing edge plate 21, the elastic mounting component 25, and the connecting frame 24, facing away from one outer surface of the blade suction surface 11, constitute the process mounting surface of the integral structure. A second flexible membrane 26 is adhered to the process mounting surface, and the circumferential edge of the second flexible membrane 26 is sealed and fixedly connected to the process mounting surface. The second flexible membrane 26 can generally be made of conventional polymer flexible membrane material. The four edges of the second flexible membrane 26 can generally be connected and fixed to the corresponding mounting surface by adhesive bonding.

[0055] Based on the aforementioned wind turbine blades, this invention also provides a horizontal axis wind turbine, including a generator, a gearbox, and a wind turbine. The wind turbine includes several blades and a horizontally mounted shaft. The blades are evenly spaced along the circumference of the shaft, and the blades are the wind turbine blades with the flexible trailing edge system 20 described above. It is understood that the main structure of the horizontal axis wind turbine in this invention is the same as that of existing technologies, and each shaft can generally be equipped with 3 to 5 blades. The key technical point is the addition of the flexible trailing edge system 20 in this invention.

[0056] Further reading Figure 13 and Figure 14In this invention, when the wind turbine blade is operating, air moves from the leading edge to the trailing edge. Under the combined action of complex aerodynamic forces and blade rotation, the entire flexible trailing edge system 20 moves accordingly. The trailing edge plate 21 of the suction surface is the main moving part of the entire structure, primarily oscillating. When the wind speed is relatively high, no flow separation occurs on the suction surface 11 of the blade, and the dynamic and static pressure changes on the trailing edge plate 21 of the suction surface are small. Therefore, its oscillation amplitude towards the pressure surface 12 of the blade is relatively small, and the equivalent blade airfoil camber change is not significant. When the wind speed decreases, flow separation occurs on the suction surface 11 of the blade, forming separation vortices. The dynamic and static pressure changes on the trailing edge plate 21 of the suction surface increase, leading to a larger oscillation amplitude towards the pressure surface 12 of the blade. This results in a larger equivalent blade airfoil camber, altering the dynamic and static pressure distribution around the airfoil, thereby reducing separation vortices, improving the flow field morphology, and exhibiting a larger airfoil lift coefficient. Further reference... Figure 15When the wind load is too large, the flexible trailing edge system 20 experiences increased force, causing the suction surface trailing edge plate 21 to tilt upwards, resulting in an unfavorable aerodynamic shape. This leads to a significant decrease in lift and a substantial increase in drag. Furthermore, its flexible vibration helps to dissipate the excessive wind load, protecting the blades and wind turbine from the risks associated with excessive loads. The above working principle indicates that the main mechanism of the flexible trailing edge system 20 in this invention is to adaptively change the equivalent airfoil camber, coupled with changes in the flow field, improving the flow field morphology, preventing or reducing separation vortices, broadening the operating conditions, and enhancing the blades' ability to capture wind energy, thereby improving the wind turbine's power generation efficiency. This invention does not require consideration of separation points; it is based on the adaptive change of camber by the suction surface trailing edge plate 21. Once the camber changes, the lift coefficient changes accordingly, demonstrating strong adaptability. The core component is the suction surface trailing edge plate 21. Because its material rigidity and thickness are greater than those of the flexible membrane in traditional solutions, it is generally less prone to self-excitation in the airflow field, greatly improving the reliability and durability of the material and structure. In this invention, the suction-side trailing edge plate 21 forms a cantilever beam structure relative to the trailing edge of the blade. The thickness of the suction-side trailing edge plate 21 is typically only 1 / 5 to 1 / 10 of the average thickness of the original trailing edge, making it closer to the theoretically shaped pointed trailing edge in terms of airfoil shape, further improving lift and reducing drag. The suction-side trailing edge plate 21, the pressure-side trailing edge plate 22, and the first flexible membrane 23 enclose the trailing edge of the blade body 10 to form a channel structure whose axial direction is consistent with the length direction of the trailing edge of the blade body 10. This channel can carry water and air. During blade operation, under the combined action of Coriolis force and aerodynamic force, high-speed gas blowing towards the blade tip will appear inside the flexible trailing edge system 20 and be blown out at the trailing edge near the blade tip, which can effectively improve the flow field near the blade tip and is beneficial to increasing blade torque. Furthermore, with the above-mentioned specific structural form, the suction surface tail edge sheet 21, the pressure surface tail edge sheet 22, and the first flexible membrane 23 do not require the development of new materials. They only meet the general engineering requirements of fatigue resistance, wear resistance, and high reliability, and can achieve good results by using existing materials.

[0057] See Figures 4 to 8 For newly manufactured wind turbine blades, in some other preferred embodiments, the end of the suction surface trailing edge piece 21 near the blade body 10 and the end of the pressure surface trailing edge piece 22 near the blade body 10 are fixedly and closedly connected by a connecting plate 27. The suction surface trailing edge piece 21, the pressure surface trailing edge piece 22 and the connecting plate 27 are integrally formed into a U-shaped structure. The outer end face of the U-shaped structure near the blade body 10 is attached to and fixedly connected to the trailing edge end face of the blade body 10.

[0058] The installation methods of other preferred solutions are basically the same as those of other solutions. Figures 1 to 3Similar to the embodiment shown, the outer end face of the U-shaped structure near the blade body 10 has an outward extension relative to the trailing edge end face of the blade body 10 on the side near the blade suction surface 11 to form a first positioning mounting surface 28 (in a preferred embodiment, the outer end face of the U-shaped structure near the blade body 10 is usually a plane extending along the thickness direction of the trailing edge of the blade body 10, and a second positioning mounting groove 15 is provided at the trailing edge of the blade body 10, and the first positioning mounting surface 28 is the part of the outer end face of the U-shaped structure that extends beyond the bottom wall of the second positioning mounting groove 15). A connecting frame 24 is attached and fixedly provided on the blade suction surface 11. The connecting frame 24 is located on the side of the suction surface trailing edge sheet 21 near the leading edge of the blade body 10. The side end face of the connecting frame 24 and the first positioning mounting surface 28 are fixedly connected to each other as a whole by an elastic mounting member 25. The elastic mounting member 25 is connected and fixed to the blade suction surface 11.

[0059] To further improve the coupling strength between the flexible trailing edge system 20 and the flow field, enhance its sensitivity to separation vortices, and improve the lift coefficient under small angle of attack conditions, the suction surface trailing edge plate 21, the elastic mounting component 25, and the connecting frame 24 are combined with an outer surface of the blade suction surface 11 to form the process mounting surface of the overall structure. A second flexible membrane 26 is attached to the process mounting surface, and the circumferential edge of the second flexible membrane 26 is sealed and fixedly connected to the process mounting surface.

[0060] To further facilitate processing and assembly, and improve overall performance, the trailing edge of the blade body 10 has a first positioning and mounting groove 13. The two ends of the first positioning and mounting groove 13 intersect with the blade suction surface 11 and the blade pressure surface 12, respectively. The bottom wall of the first positioning and mounting groove 13 is a second positioning and mounting surface 14, which is the trailing edge end face of the blade body 10 used to connect with the outer end face of the U-shaped structure near the blade body 10. The two side end faces of the U-shaped structure corresponding to the spanwise direction of the blade body 10 have corresponding fitting clearances relative to the two inner side walls of the first positioning and mounting groove 13. The free end face of the suction surface tail edge plate 21 is flush with or located outside the first positioning and mounting groove 13 (the outer end face of the first positioning and mounting groove 13 refers to the original end face of the trailing edge of the blade body 10 without the first positioning and mounting groove 13); the blade suction surface 11 is provided with a second positioning and mounting groove 15 on the side of the first positioning and mounting groove 13 near the leading edge of the blade body 10. The end of the second positioning and mounting groove 15 near the U-shaped structure intersects with the second positioning and mounting surface 14. The elastic mounting member 25 and the connecting frame 24 are both fixed in the second positioning and mounting groove 15.

[0061] To achieve relatively better overall performance, the specific preferred parameters in the above scheme are as follows: the overhang length of the free end of the suction surface trailing edge plate 21 relative to the connecting plate 27 is set to L5, and the overhang length of the free end of the pressure surface trailing edge plate 22 relative to the connecting plate 27 is set to L6, with L6 being 1 / 2 to 2 / 3 of the value of L5; the overhang length of the free end of the suction surface trailing edge plate 21 relative to the outer end face of the first positioning mounting groove 13 is not greater than 20% of the chordal length of the blade body 10.

[0062] To enhance structural reliability, a water-resistant corrosion-resistant component 29 is fixedly installed on the inner wall of the channel structure at the trailing edge of the blade body 10. This component 29 is located on the side of the channel structure near the leading edge of the blade body 10 and extends axially along the channel structure. The water-resistant corrosion-resistant component 29 primarily absorbs the impact flow energy of water droplets or water flow passing through the flexible trailing edge system 20, thus better protecting the structure from damage. The water-resistant corrosion-resistant component 29 is generally made of a soft material with a certain degree of elasticity. Its installation and fixing are also based on conventional techniques, including adhesive bonding, bolting, riveting, or any combination of these methods.

[0063] To enhance structural reliability, an elastic limiting member 210 is fixedly installed on the inner wall of the channel structure at the trailing edge of the blade body 10. The elastic limiting member 210 is connected to the pressure surface trailing edge plate 22 and extends axially along the channel structure. The elastic limiting member 210 is typically made of a high-polymer elastic material, and its height is set according to the deformation design requirements of the suction surface trailing edge plate 21. The main function of the elastic limiting member 210 is to limit the swing or deformation amplitude of the suction surface trailing edge plate 21 using its material elasticity. Within the normal wind load range, if the suction surface trailing edge plate 21 moves too violently or undergoes extreme deformation, it will exacerbate the deterioration of the flow field, leading to a decrease in lift and an increase in drag. Therefore, the elastic limiting member 210 is installed to limit the movement amplitude of the suction surface trailing edge plate 21, ensuring that the swing angle of the suction surface trailing edge plate 21 does not exceed the designed maximum swing angle θ2. This also protects the structural materials from damage and improves the reliability and durability of the flexible trailing edge system 20. The installation and fixing of the elastic limiting component 210 is also a conventional technique, which can be adhesive bonding, bolt connection, or riveting, or any combination of adhesive bonding, bolt connection, riveting and other fixing methods.

[0064] To ensure a simple and reliable structure that is easy to process and assemble, the first end of the first flexible membrane 23 is attached to and fixedly connected to the free end of the suction surface tail edge sheet 21 facing the pressure surface tail edge sheet 22, and the second end of the first flexible membrane 23 is attached to and fixedly connected to the free end of the pressure surface tail edge sheet 22 facing away from the suction surface tail edge sheet 21.

[0065] See Figure 12 To help eliminate aerodynamic noise, the free end face of the suction surface trailing edge plate 21 is a toothed surface 211, and the protrusions and grooves of the toothed surface 211 are arranged alternately along the trailing edge length direction of the blade body 10.

[0066] To achieve relatively better overall performance, some other preferred parameters in the above scheme are as follows: one end of the blade body 10 in the spanwise direction is the blade root 16, and the other end is the blade tip 17. The spanwise length of the blade body 10 is set to L1. The starting point of the flexible trailing edge system 20 on the trailing edge end face of the blade body 10 is set to point A, and the ending point is set to point B. The flexible trailing edge system 20 is continuously or intermittently arranged in the area between points A and B. The distance between points A and B in the spanwise direction of the blade body 10 is set to L2, and L2 is 20% to 70% of L1. Point A is closer to the blade tip 17 than point B. The distance between points A and the blade tip 17 in the spanwise direction of the blade body 10 is not less than 10% of L1. The distance between points B and the blade root 16 in the spanwise direction of the blade body 10 is not less than 20% of L1. For the specific arrangement of the flexible trailing edge system 20, please refer to [reference needed]. Figures 9 to 11 .

[0067] The wind turbine blades of this invention generally include at least the following steps in their specific manufacturing process:

[0068] Step 1: The blade body 10 and the flexible trailing edge system 20 are pre-processed separately;

[0069] Step 2: Assemble the blade body 10 and the flexible trailing edge system 20 at the installation site of the wind turbine generator set. When connecting the free end of the fixed pressure surface trailing edge plate 22 and the first flexible membrane 23, control the relative position of the first flexible membrane 23 and the pressure surface trailing edge plate 22 so that the free end of the suction surface trailing edge plate 21 has a preset initial installation angle θ1 relative to the blade pressure surface 12.

[0070] In the preferred embodiment, the initial installation angle θ1 of the free end of the suction surface trailing edge plate 21 described in step two is set as follows: the proportion of wind frequency below half the rated wind speed of the wind turbine generator is set as M. The value of θ1 is adjusted linearly within the range of 0 to 30° based on the value of M. If the value of M is 100%, then the value of θ1 is 30°; if the value of M is 0, then the value of θ1 is 0°. The variation of this initial installation angle θ1 directly affects the important camber parameter of the blade airfoil. The larger the initial installation angle θ1, the greater the camber of the blade airfoil, and the greater the maximum lift coefficient of the blade airfoil. The flexible trailing edge system 20 in this invention can specifically adjust the initial installation angle θ1 according to the on-site wind environment. This adjusts an important parameter of the blade airfoil, "camber," thereby balancing and optimizing the lift and drag coefficients and improving power generation efficiency.

[0071] This invention selected some preferred embodiments and conducted comparative experiments with existing conventional blades. Experimental Example 1 of this invention uses... Figures 1 to 3 The structural scheme shown is different from that of Experimental Example 1, but without the second flexible membrane 26. Experimental Example 2 of this invention has the same main structure as Experimental Example 1, but adds a second flexible membrane 26. Existing conventional blades refer to... Figure 14 The conventional leaves in the specimen. Related experimental results can be found in [reference needed]. Figure 16 and Figure 17 .

[0072] from Figure 16 It can be seen that, in terms of lift coefficient, Experimental Example 1 and Experimental Example 2 of this invention are significantly superior to existing conventional blades, with the lift coefficient increasing by up to 77%. The effects of Experimental Example 2 and Experimental Example 1 are roughly the same, except that Experimental Example 2 shows a slight improvement under low angle of attack conditions, which also indicates that the basic design corresponding to Experimental Example 1 plays the main role.

[0073] from Figure 17 It can be seen that, in terms of drag coefficient, Experimental Example 1 and Experimental Example 2 of this invention are significantly better than existing conventional blades, with drag coefficient reduction of up to 50%. The effects of Experimental Example 2 and Experimental Example 1 are roughly the same, but under small angle of attack conditions, the drag coefficient of the scheme with added membrane (Experimental Example 2) is greater than that of the basic scheme (Experimental Example 1), showing its disadvantage.

[0074] Considering the lift and drag coefficients, the membrane addition scheme (Experimental Example 2) did not show a significant advantage over the basic scheme (Experimental Example 1); under the premise that drag is not a significant factor, the membrane addition scheme can partially improve lift at small angles of attack.

[0075] In addition, the above-mentioned experimental examples of this utility model were also used for field verification of wind turbines, and the results showed that the power generation of the wind turbines was increased by more than 20% compared with existing conventional blades.

[0076] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention.

Claims

1. A wind turbine blade, comprising a blade body (10), one side surface of the blade body (10) being a blade suction surface (11) and the other side surface being a blade pressure surface (12), and a flexible trailing edge system (20) provided at the trailing edge of the blade body (10), the flexible trailing edge system (20) comprising a first flexible membrane (23), characterized in that: The flexible trailing edge system (20) also includes a suction-side trailing edge plate (21) and a pressure-side trailing edge plate (22); The suction surface trailing edge plate (21) is fixedly disposed at the trailing edge of the suction surface (11) of the blade. The suction surface trailing edge plate (21) has a free end that extends away from the trailing edge of the blade body (10) in a direction away from the blade body (10). The pressure surface trailing edge plate (22) is fixedly disposed at the trailing edge of the blade pressure surface (12). The pressure surface trailing edge plate (22) has a free end that extends away from the blade body (10) relative to the trailing edge of the blade body (10). The suction surface trailing edge plate (21) and the pressure surface trailing edge plate (22) are arranged opposite to each other. The overhang length of the free end of the suction surface trailing edge plate (21) relative to the trailing edge of the blade body (10) is greater than the overhang length of the free end of the pressure surface trailing edge plate (22) relative to the trailing edge of the blade body (10). The free ends of the suction surface trailing edge plate (21) and the pressure surface trailing edge plate (22) are connected by a first flexible membrane (23) to form a closed connection, so that the suction surface trailing edge plate (21), the pressure surface trailing edge plate (22) and the first flexible membrane (23) surround the trailing edge of the blade body (10) to form a channel structure whose axial direction is consistent with the length direction of the trailing edge of the blade body (10).

2. The wind turbine blade as described in claim 1, characterized in that: The end of the suction surface trailing edge piece (21) near the blade body (10) is attached to and connected to the blade suction surface (11); the end of the pressure surface trailing edge piece (22) near the blade body (10) is attached to and connected to the blade pressure surface (12).

3. The wind turbine blade as described in claim 2, characterized in that: A connecting frame (24) is fixedly attached to the suction surface (11) of the blade. The connecting frame (24) is located on the side of the trailing edge piece (21) of the suction surface near the leading edge of the blade body (10). The side end face of the connecting frame (24) and the side end face of the trailing edge piece (21) of the suction surface are fixedly connected to each other as a whole by an elastic mounting piece (25). The elastic mounting piece (25) is fixedly connected to the suction surface (11) of the blade.

4. The wind turbine blade as described in claim 3, characterized in that: The suction surface tail edge plate (21), elastic mounting piece (25), and connecting frame (24) are combined on an outer surface of the blade suction surface (11) to form the process mounting surface of the overall structure. A second flexible membrane (26) is attached to the process mounting surface, and the circumferential edge of the second flexible membrane (26) is sealed and fixedly connected to the process mounting surface.

5. The wind turbine blade as described in claim 2, characterized in that: The overhang length of the free end of the suction surface trailing edge plate (21) relative to the trailing edge of the blade body (10) is set to L3, and the overhang length of the free end of the pressure surface trailing edge plate (22) relative to the trailing edge of the blade body (10) is set to L4. The value of L4 is 1 / 2 to 2 / 3 of the value of L3. The value of L3 is 10% to 20% of the chord length of the blade body (10).

6. The wind turbine blade as described in claim 1, characterized in that: The end of the suction surface trailing edge piece (21) near the blade body (10) and the end of the pressure surface trailing edge piece (22) near the blade body (10) are fixedly and closedly connected by a connecting plate (27). The suction surface trailing edge piece (21), the pressure surface trailing edge piece (22) and the connecting plate (27) are integrally formed into a U-shaped structure. The outer end face of the U-shaped structure near the blade body (10) is attached to and fixedly connected to the trailing edge end face of the blade body (10).

7. The wind turbine blade as described in claim 5, characterized in that: The outer end face of the U-shaped structure near the blade body (10) has an outer extension relative to the trailing edge end face of the blade body (10) on the side near the blade suction surface (11) to form a first positioning mounting surface (28). A connecting frame (24) is attached and fixedly provided on the blade suction surface (11). The connecting frame (24) is located on the side of the suction surface trailing edge piece (21) near the leading edge end of the blade body (10). The side end face of the connecting frame (24) and the first positioning mounting surface (28) are fixedly connected to each other as a whole by an elastic mounting member (25). The elastic mounting member (25) is connected and fixed to the blade suction surface (11).

8. The wind turbine blade as described in claim 7, characterized in that: The suction surface tail edge plate (21), elastic mounting piece (25), and connecting frame (24) are combined on an outer surface of the blade suction surface (11) to form the process mounting surface of the overall structure. A second flexible membrane (26) is attached to the process mounting surface, and the circumferential edge of the second flexible membrane (26) is sealed and fixedly connected to the process mounting surface.

9. The wind turbine blade as described in claim 7, characterized in that: The trailing edge of the blade body (10) has a first positioning mounting groove (13). The two ends of the first positioning mounting groove (13) intersect with the blade suction surface (11) and the blade pressure surface (12) respectively. The bottom wall of the first positioning mounting groove (13) is a second positioning mounting surface (14). The second positioning mounting surface (14) is the trailing edge end face of the blade body (10) used to connect with the outer end face of the U-shaped structure near the blade body (10). The two side end faces of the U-shaped structure in the spanwise direction corresponding to the blade body (10) have corresponding fitting gaps with the two inner side walls of the first positioning mounting groove (13). The free end face of the suction surface trailing edge plate (21) is flush with or located outside the first positioning mounting groove (13) and the outer end face of the first positioning mounting groove (13). The blade suction surface (11) is provided with a second positioning mounting groove (15) on the side of the first positioning mounting groove (13) near the leading edge of the blade body (10). The second positioning mounting groove (15) intersects with the second positioning mounting surface (14) at one end near the U-shaped structure. The elastic mounting component (25) and the connecting frame (24) are both fixed in the second positioning mounting groove (15).

10. The wind turbine blade as described in claim 9, characterized in that: The overhang length of the free end of the suction surface trailing edge plate (21) relative to the connecting plate (27) is set to L5, and the overhang length of the free end of the pressure surface trailing edge plate (22) relative to the connecting plate (27) is set to L6. The value of L6 is 1 / 2 to 2 / 3 of the value of L5. The overhang length of the free end of the suction surface trailing edge plate (21) relative to the outer end face of the first positioning mounting groove (13) is not greater than 20% of the chord length of the blade body (10).

11. The wind turbine blade as described in any one of claims 1 to 10, characterized in that: A waterproof corrosion-resistant component (29) is fixedly installed on the inner wall of the channel structure at the trailing edge of the blade body (10). The waterproof corrosion-resistant component (29) is located on the side of the channel structure near the leading edge of the blade body (10) and extends along the axial direction of the channel structure.

12. The wind turbine blade as described in any one of claims 1 to 10, characterized in that: An elastic limiting member (210) is fixedly provided on the inner wall of the channel structure at the trailing edge of the blade body (10). The elastic limiting member (210) is connected to the pressure surface trailing edge plate (22) and extends along the axial direction of the channel structure.

13. The wind turbine blade as described in any one of claims 1 to 10, characterized in that: The first end of the first flexible membrane (23) is attached to and fixedly connected to the free end of the suction surface tail edge sheet (21) facing the pressure surface tail edge sheet (22), and the second end of the first flexible membrane (23) is attached to and fixedly connected to the free end of the pressure surface tail edge sheet (22) facing away from the suction surface tail edge sheet (21).

14. The wind turbine blade as described in claim 13, characterized in that: The free end face of the suction surface trailing edge plate (21) is a toothed surface (211), and the protrusions and grooves of the toothed surface (211) are arranged alternately along the trailing edge length direction of the blade body (10).

15. The wind turbine blade as described in any one of claims 1 to 10, characterized in that: One end of the blade body (10) in the spanwise direction is the root end (16) and the other end is the tip end (17). The spanwise length of the blade body (10) is set as L1. The starting point of the flexible trailing edge system (20) arrangement area on the trailing edge end face of the blade body (10) is set as point A and the ending point is set as point B. The flexible trailing edge system (20) is arranged continuously or intermittently in the area between point A and point B. The distance between point A and point B in the spanwise direction of the blade body (10) is set as L2. The value of L2 is 20% to 70% of L1. Point A is closer to the tip end (17) than point B. The distance between point A and the tip end (17) in the spanwise direction of the blade body (10) is not less than 10% of L1. The distance between point B and the root end (16) in the spanwise direction of the blade body (10) is not less than 20% of L1.

16. A horizontal-axis wind turbine, comprising a generator, a gearbox, and a wind turbine, the wind turbine comprising a plurality of blades and a horizontally mounted shaft, the plurality of blades being mounted at equal intervals along the circumference of the shaft, characterized in that, The blades are wind turbine blades as described in any one of claims 1 to 15.

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