Wind power tower blade wing type auxiliary stress structure

Abstract

The invention belongs to the field of wind power equipment, and particularly relates to a wind power tower blade airfoil-shaped auxiliary stress structure which comprises a blade body, an airfoil-shaped auxiliary plate extends out of the side direction of the blade body, the side, close to the root of the blade body, of the airfoil-shaped auxiliary plate is a suction surface, and the side, close to the tip of the blade body, of the airfoil-shaped auxiliary plate is a pressure surface. Comprising a blade body, a wing-shaped auxiliary plate extends out of the side direction of the blade body, the side, close to the root of the blade body, of the wing-shaped auxiliary plate is a suction face, and the side, close to the tip of the blade body, of the wing-shaped auxiliary plate is a pressure face.

Description

Technical Field

[0001] This invention belongs to the field of wind power equipment, specifically relating to an auxiliary force-bearing structure for wind turbine tower blade airfoils. Background Technology

[0002] As the wind power industry develops towards higher power and lower cost, the size of wind turbine blades is constantly increasing. For large and even ultra-large wind turbine blades exceeding 70 meters in length, the dynamic loads they bear during rotation increase dramatically. (See attached image) Figure 7 As shown, when a blade rotates to a vertically downward position (pointing towards the ground), its own weight and the centrifugal force of rotation are in the same direction. The superposition of these two forces at the blade root generates a huge bending moment, which is one of the most significant operating conditions leading to blade fatigue damage and even structural failure. Current technologies typically address this problem by strengthening the blade's material strength, increasing ply thickness, or optimizing the main sparsity cap structure. These are all passive reinforcement methods, significantly increasing blade weight and manufacturing costs, and potentially negatively impacting aerodynamic performance. Some studies have attempted to adjust the load through aerodynamic shape optimization, but these often focus on overall airfoil modifications and are insufficient for precise and efficient improvement under this specific instantaneous operating condition. Therefore, a solution is urgently needed that can actively and efficiently counteract the peak bending moment experienced by the blade at a specific location without excessively increasing weight and cost. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides an auxiliary force-bearing structure for wind turbine tower blade airfoils.

[0004] The objective of this invention is achieved in the following manner: a wind turbine tower blade airfoil auxiliary force-bearing structure, comprising a blade body 1, an airfoil auxiliary plate 2 extending outward in the lateral direction of the blade body 1, the side of the airfoil auxiliary plate 2 near the root of the blade body 1 being a suction surface 4, and the side of the airfoil auxiliary plate 2 near the tip of the blade body 1 being a pressure surface 5.

[0005] Furthermore, the airfoil auxiliary plate 2 extends from the blade body 1 to opposite sides.

[0006] Furthermore, the airfoil auxiliary plate 2 includes one fixed to the tip of the blade body 1 and 2-3 spaced apart on the blade body 1.

[0007] Furthermore, the suction surface 4 starts from the leading edge near the front side of the blade body 1 in the direction of rotation, forming a raised section. After the raised section, a middle arc line is connected. The middle arc line is a gentle and continuous convex shape. After the middle arc line, the curvature gradually decreases to the rear edge of the blade body 1 in the direction of rotation.

[0008] Furthermore, the airfoil auxiliary plate 2 is disposed within a range of 30%-60% of the length of the blade body 1, starting from the tip of the blade body 1.

[0009] Furthermore, the maximum distance between the suction surface 4 and the pressure surface 5 is 140mm~1100mm.

[0010] Furthermore, the distance by which the airfoil auxiliary plate 2 extends from the blade body 1 is 30% to 70% of the maximum thickness of the blade body 1.

[0011] Compared to existing technologies, this invention designs specific suction and pressure surfaces on the extended airfoil auxiliary plate. When the blade rotates to face the ground, this auxiliary plate can utilize the incoming airflow to generate significant aerodynamic lift. The direction of this lift is optimized to effectively counteract some of the huge bending moment generated at the root by the blade's own weight and centrifugal force, thereby actively and precisely protecting the most vulnerable parts of the blade. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the airfoil-assisted stress-bearing structure of a wind turbine tower blade; Figure 2 This is a front view of the airfoil-assisted load-bearing structure of a wind turbine tower blade; Figure 3 This is a partial perspective view of the auxiliary stress-bearing structure of the wind turbine tower blade airfoil; Figure 4 This is a schematic diagram of the auxiliary force-bearing structure of the wind turbine tower blade pattern; Figure 5 This is a front view of the auxiliary load-bearing structure of the wind turbine tower blade pattern; Figure 6 This is a partial perspective view of the auxiliary load-bearing structure of the wind turbine tower blade pattern; Figure 7 This is a diagram illustrating the force distribution principle of the blade.

[0013] The blade body 1, airfoil auxiliary plate 2, guide rib 3, suction surface 4, and pressure surface 5 are included. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] In this invention, unless otherwise explicitly specified and limited, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0016] As attached Figure 7 As shown, when the blade rotates to a vertically downward position (pointing towards the ground), its own weight and the centrifugal force of rotation are in the same direction. The two superimposed on the root of the blade generate a huge bending moment, which is one of the main working conditions that lead to fatigue damage and even structural failure of the blade.

[0017] As attached Figure 1-3 As shown, a wind turbine tower blade airfoil auxiliary force-bearing structure includes a blade body 1, an airfoil auxiliary plate 2 extending outward in the lateral direction of the blade body 1, a suction surface 4 on the side of the airfoil auxiliary plate 2 near the root of the blade body 1, and a pressure surface 5 on the side of the airfoil auxiliary plate 2 near the tip of the blade body 1.

[0018] Blade body 1: This is the main structure of the wind turbine blade, with a conventional airfoil profile.

[0019] Airfoil auxiliary plate 2: This is a core feature of the invention. It is fixedly connected to the side of the blade body 1 and extends outward. The auxiliary plate 2 itself has an independent, optimized airfoil profile.

[0020] Suction surface 4: Located on the side of the airfoil auxiliary plate 2 near the root of the blade body 1, i.e., the front side in the direction of rotation.

[0021] Pressure surface 5: Located on the side of the airfoil auxiliary plate 2 near the tip of the blade body 1, i.e., the rear side in the direction of rotation.

[0022] Operating logic: The airfoil auxiliary plate 2 is equivalent to a functionally independent "mini wing". When the blade rotates, the airflow passing through its suction surface 4 and pressure surface 5 will generate a pressure difference, thereby forming aerodynamic lift. By fixing the auxiliary plate 2 to the side of the blade at a specific angle, this lift can generate an upward component when the blade is in a critical orientation (such as vertically downward), directly offsetting part of the huge root bending moment generated by the superposition of gravity and centrifugal force.

[0023] By designing specific suction and pressure surfaces on the extended airfoil auxiliary plate, the plate can generate significant aerodynamic lift using the incoming airflow when the blade rotates to face the ground. The direction of this lift is optimized to effectively counteract some of the huge bending moment generated at the root by the blade's own weight and centrifugal force, thereby actively and precisely protecting the most vulnerable parts of the blade.

[0024] Furthermore, the airfoil auxiliary plate 2 extends from the blade body 1 to opposite sides. This arrangement can balance aerodynamic loads and avoid introducing asymmetrical torsional moments.

[0025] Furthermore, the airfoil auxiliary plate 2 includes one fixed to the tip of the blade body 1, and 2-3 spaced apart on the blade body 1. This multi-point arrangement can provide continuous and uniform auxiliary support for the section with the largest bending moment in the blade spanwise direction.

[0026] The connection between the airfoil auxiliary plate 2 and the blade body 1 can be achieved by integral molding (such as integral manufacturing during blade injection) or post-assembly (such as bonding with high-strength structural adhesive and mechanically fastening with bolts). Its installation angle (i.e., the angle between the airfoil chord and the blade principal chord) is a key design variable that needs to be optimized through aerodynamic calculations to ensure that the optimal upward lift component can be generated under the target operating conditions.

[0027] Furthermore, the suction surface 4 starts from the leading edge near the front side of the blade body 1 in the direction of rotation, forming a raised section. After the raised section, a middle arc line is connected. The middle arc line is a gentle and continuous convex shape. After the middle arc line, the curvature gradually decreases to the rear edge of the blade body 1 in the direction of rotation.

[0028] Leading edge protrusion: Starting from the leading edge near the front side of the rotation direction, the profile protrudes outward with a large curvature, forming a smooth head that facilitates smooth airflow adhesion.

[0029] The main section of the camber line: This section connects to the convex section. This part of the profile features a gentle, continuous convexity with mild curvature changes, and is the main section that generates a stable low-pressure area.

[0030] Trailing Edge: The curve transitions from the central arc to the trailing edge on the rear side of the rotation direction. The curvature of the profile gradually decreases and converges smoothly to ensure that the airflow can escape cleanly and reduce drag.

[0031] Furthermore, the airfoil auxiliary plate 2 is set within a range of 30%-60% of the length of the blade body 1, starting from the tip of the blade body 1. This is a position optimized through aeroelastic analysis. For large blades over 70 meters, this area is the key area of ​​aerodynamic load center and bending moment. Arranging the auxiliary lift enhancement structure here can obtain the maximum bending resistance benefit with minimal structural intervention, resulting in the highest efficiency.

[0032] Furthermore, the maximum distance between the suction surface 4 and the pressure surface 5 is 140mm~1100mm. Generally, in the transition / middle region of the blade with a span of 50%-80% from the blade root, the chord length is 3.5m-4.5m, which is 290mm~1100mm; in the outer wing / tip region with a span of 80%-100% from the blade root, the chord length is 1.0m-1.8m, which is 140mm~290mm. Furthermore, the distance by which the airfoil auxiliary plate 2 extends from the blade body 1 is 30% to 70% of the maximum thickness of the blade body 1, so that the auxiliary plate has sufficient lever arm to generate an effective bending moment, while avoiding structural connection risks, excessive additional weight, and excessive interference with the aerodynamic performance of the main blade caused by excessive extension.

[0033] At most wind speeds and blade azimuth angles, the airfoil auxiliary plate 2, as a fixed component on the blade surface, shares the aerodynamic load with the main blade, and the direction of the lift it generates dynamically changes with the blade azimuth angle; when the blade rotates to a near-vertical downward azimuth (such as... Figure 7 As shown in the principle, the blade's own weight and the direction of the rotational centrifugal force are in the same direction, generating a peak bending moment at the root. At this time, the incoming flow direction forms a specific favorable angle of attack with the chord plane of the airfoil auxiliary plate 2; at the aforementioned angle of attack, the airflow flows through the airfoil auxiliary plate 2. According to Bernoulli's principle, the airflow accelerates on the convex suction surface 4, forming a low-pressure area; the speed is slower on the relatively flat pressure surface 5, maintaining a higher pressure. This pressure difference combines into an aerodynamic lift perpendicular to the incoming flow direction; since the airfoil auxiliary plate 2 is pre-fixed at a specific angle, the aerodynamic lift it generates in the critical orientation includes an upward vector component. This upward force forms a moment at the blade root opposite to the direction of the gravity / centrifugal force bending moment, thereby actively offsetting part of the peak load; as the blade continues to rotate, the magnitude and direction of the lift generated by the auxiliary plate continue to change, but by optimizing its installation position and angle, the system is designed to provide maximum auxiliary support in the orientation of the maximum load, thereby achieving active "peak shaving and valley filling" of the load spectrum throughout the entire rotation cycle, significantly improving blade fatigue life and operational safety.

[0034] As an alternative, see attached Figure 4-6As shown, a textured auxiliary force-bearing structure for wind turbine tower blades includes a blade body 1. A flow-guiding rib 3 is provided on the side of the blade body 1. The side of the flow-guiding rib 3 near the root of the blade body 1 is a suction surface 4, and the side of the flow-guiding rib 3 near the tip of the blade body 1 is a pressure surface 5. Several flow-guiding ribs 3 are spaced apart along the length of the blade body 1 to form a textured structure.

[0035] Blade body 1: This is the main structure of the wind turbine blade, featuring a conventional airfoil profile and aerodynamic shape.

[0036] Guide ribs 3: This is the core feature of the invention. Multiple guide ribs 3 are arranged at predetermined intervals along the length (span) of the blade body 1. As shown in the attached figures, these ribs are not simply straight protrusions; their arrangement can be designed as oblique lines at a certain angle to the blade chord or as continuous wavy or spiral patterns, thereby more effectively managing three-dimensional flow. Each guide rib 3 itself has an optimized micro-airfoil profile, which includes: Suction surface 4: Located on the side of the guide rib 3 near the root of the blade body 1 (i.e., the front side in the direction of rotation).

[0037] Pressure surface 5: Located on the side of the guide rib 3 near the tip of the blade body 1 (i.e., the rear side in the direction of rotation).

[0038] Through their surface protrusions, these guide ribs 3 actively intervene in the boundary layer flow on the blade surface. When the blade rotates to a specific orientation (e.g., vertically downward), these guide ribs 3 work together to induce a series of scale-controlled stable vortices on its suction surface 4. These vortices accelerate the upper airflow and delay flow separation, thereby forming a continuous and stronger low-pressure zone on the upper surface of the entire rib-covered area. Combined with the high-pressure zone on the pressure surface 5, this ultimately synthesizes a significant aerodynamic force with an upward component, providing "aerodynamic support" for the blade body.

[0039] Furthermore, the guide ribs 3 extend from the blade body 1 to opposite sides.

[0040] The guide rib 3 can be integrally molded with the blade body 1, such as by forming it in one step in the blade mold through special profiles, or it can be used as an independent composite material strip and then attached to a specific position on the blade surface with high-performance structural adhesive.

[0041] Furthermore, the suction surface 4 starts from the leading edge near the front side of the blade body 1 in the direction of rotation, forming a raised section. After the raised section, a middle arc line is connected. The middle arc line is a gentle and continuous convex shape. After the middle arc line, the curvature gradually decreases to the rear edge of the blade body 1 in the direction of rotation.

[0042] Furthermore, the guide ribs 3 are disposed within a range of 30%-60% of the length of the blade body 1, starting from the tip of the blade body 1.

[0043] Furthermore, the maximum distance between the suction surface 4 and the pressure surface 5 is x, where x ranges from 50mm to 800mm.

[0044] Furthermore, the minimum spacing between adjacent guide ribs 3 is greater than or equal to x.

[0045] The spacing being greater than or equal to the thickness ensures that: There is enough space for airflow to pass smoothly between the ribs, avoiding flow blockage.

[0046] The vortices induced by each rib can develop fully and produce beneficial synergy with the flow fields of adjacent ribs, rather than interfering with each other.

[0047] Furthermore, the distance by which the airfoil auxiliary plate 2 extends from the blade body 1 is 1 / 20 to 1 / 10 of the maximum thickness of the blade body 1.

[0048] Under most operating conditions, the guide ribs on the blade surface continuously function, their core role being to streamline the boundary layer flow on the blade surface. The spiral or oblique patterns guide spanwise flow, enhancing airflow adhesion and thus slightly improving the blade's aerodynamic efficiency or delaying stall under all operating conditions, achieving a "passive gain" effect. When the blade rotates to a vertically downward or near-downward orientation (i.e., the instant when gravity and centrifugal force are superimposed in the same direction, causing a sharp increase in root bending moment), the incoming flow direction and the pattern structure form a specific spatial relationship. At this specific angle of attack, each guide rib 3 becomes a highly efficient micro-vortex generator. The profile of its suction surface 4 promotes accelerated airflow separation, dragging out a stable vortex behind the rib. Because multiple ribs are arranged at regular intervals, these vortices form an ordered array in both spanwise and flowwise directions. This vortex array effectively "excites" the boundary layer on the upper surface of the blade, enabling it to resist a larger adverse pressure gradient without separation, thereby forming a stronger and more stable low-pressure distribution throughout the pattern-covered area. The pressure difference between this low pressure and the lower surface (pressure side) combines to form an upward-directed force distributed throughout the region, known as "aerodynamic buoyancy." This upward-directed force generates a moment at the blade root that is opposite to the direction of gravity / centrifugal bending moment. Because the grooves are precisely arranged in the 30%-60% span region where the bending moment is greatest, they can offset the peak stress at that location with the highest efficiency, achieving precise unloading by providing support wherever it is needed. As the blade continues to rotate and the airflow angle of attack changes, the intensity of the vortex generated by the grooves and the magnitude of the induced lift also change smoothly, forming a dynamic protection system synchronized with the rotation cycle. This continuously smooths the load spectrum, significantly improving the fatigue life and operational reliability of the blades, especially large blades.

[0049] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several changes and improvements without departing from the overall concept of the present invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. An auxiliary force-bearing structure for wind turbine tower blades, characterized in that: It includes a blade body (1), an airfoil auxiliary plate (2) extending outward from the side of the blade body (1), the side of the airfoil auxiliary plate (2) near the root of the blade body (1) is a suction surface (4), and the side of the airfoil auxiliary plate (2) near the tip of the blade body (1) is a pressure surface (5).

2. The wind turbine tower blade airfoil auxiliary force-bearing structure as described in claim 1, characterized in that: The airfoil auxiliary plate (2) extends from the blade body (1) to opposite sides.

3. The wind turbine tower blade airfoil auxiliary force-bearing structure as described in claim 2, characterized in that: The airfoil auxiliary plate (2) includes one fixed to the tip of the blade body (1) and two to three spaced apart on the blade body (1).

4. The wind turbine tower blade airfoil auxiliary force-bearing structure as described in claim 1, characterized in that: The suction surface (4) starts from the leading edge near the front side of the blade body (1) in the direction of rotation, forming a raised section. After the raised section, a middle arc line is connected. The middle arc line is a gentle and continuous raised section. After the middle arc line, the curvature gradually decreases to the rear edge of the blade body (1) in the direction of rotation.

5. The wind turbine tower blade airfoil auxiliary force-bearing structure as described in claim 1, characterized in that: The airfoil auxiliary plate (2) is located within a range of 30%-60% of the length of the blade body (1), starting from the tip of the blade body (1).

6. The wind turbine tower blade airfoil auxiliary force-bearing structure as described in claim 1, characterized in that: The maximum distance between the suction surface (4) and the pressure surface (5) is 140mm~1100mm.

7. The wind turbine tower blade airfoil auxiliary force-bearing structure as described in claim 1, characterized in that: The airfoil auxiliary plate (2) extends from the blade body (1) by a distance of 30% to 70% of the maximum thickness of the blade body (1).

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