Wind turbine blade liquid damper with spoiler, pre-fabrication method and wind turbine blade

Abstract

This invention discloses a liquid damper for wind turbine blades with a turbulent fluid, a prefabrication method, and a wind turbine blade. The liquid damper includes an elongated tube, a turbulent fluid, and a damping fluid. Multiple elongated tubes are arranged side-by-side at predetermined intervals on the inner surfaces of the SS and PS of the wind turbine blade, located at the blade tip. Each elongated tube is connected at its two ends to the leading and trailing edges of the wind turbine blade, respectively. The central axis of each elongated tube is perpendicular to the pitch shaft of the wind turbine blade. The turbulent fluid is embedded within the elongated tube and fixedly connected to its inner wall, serving to impede the flow of the damping fluid along the central axis of the elongated tube. The damping fluid is filled with the elongated tube at a predetermined volumetric filling rate, causing the damping fluid to be constrained and reciprocate along the central axis of the elongated tube. The centrifugal force direction is always perpendicular to the damping fluid's trajectory. This invention can effectively suppress the first-order oscillation of the wind turbine blade, achieving the maintenance-free characteristic of the liquid damper throughout its lifespan.

Description

Technical Field

[0001] This invention relates to the technical field of wind turbine blade dampers, and in particular to a liquid damper for wind turbine blades with turbulent fluid, a prefabrication method, and the wind turbine blade itself. Background Technology

[0002] The manufacturing technology of wind turbine power generation equipment is advancing rapidly. The single-unit capacity of the equipment has exceeded 20MW, the blade length exceeds 100 meters, and the hub height of the turbine has exceeded 150m, etc., and the cost of the equipment is also increasing. Faced with complex wind resources and conditions, the risk of blade damage is also increasing. Wind turbine blades are slender shell structures that are very flexible. In complex and variable strong gusts, vibration problems are very prominent, especially the first-order mode vibration in the wobbling direction. If the vibration is not effectively damped and suppressed, it will seriously affect the fatigue life of the blade, and resonance can even lead to the catastrophic failure of the blade.

[0003] Among existing tuned mass damping technologies, there are electroturbulence dampers and liquid mass dampers. Electroturbulence damping technology suffers from high costs and issues with lifespan and reliability, making it difficult to achieve the desired performance. Liquid mass damping, on the other hand, inherently possesses excellent reliability properties, thus becoming a focus of research. Existing liquid mass dampers have been applied in bridges and high-rise buildings, but their application in blades is not yet mature. This is because the damping mechanism of liquid mass dampers used in buildings cannot be fully utilized under the rotational conditions of blades. For example, the patent application No. 99811451.0, "Wind Turbine Blade with U-shaped Vibration Damping Device," and the patent application No. 201610959925.8, "A Circular Tube Liquid Damper for Reducing Edge Vibration of Wind Turbine Blades," share a common drawback. On the one hand, because the U-shaped and O-shaped liquid tubes described in the patents have their tube planes parallel to the blade pitch axis, under the enormous centrifugal force during impeller rotation, the depth of the tube in the direction of the centrifugal force is too large. The enormous centrifugal force cannot generate a liquid dynamic pressure difference, and the damping mechanism of the liquid damper is basically ineffective due to the presence of centrifugal force, thus failing to play a damping role. On the other hand, during the hoisting stage or when the machine is stopped, the phase position and blade attitude on the impeller are random. When the blade axis is horizontal, the U-shaped and O-shaped dampers will lose their damping mechanism and fail, and only when the blade is vertically pointing towards the ground will they have a relatively ideal damping effect. This means that its damping mechanism is to use the dynamic pressure difference of the sloshing liquid to tune the damping. These liquid dampers have not been able to combine the working state of the blades with the liquid damping mechanism well, so their practicality is poor. Summary of the Invention

[0004] The primary objective of this invention is to address the shortcomings of existing technologies by providing a liquid damper for wind turbine blades with turbulent flow characteristics, effectively suppressing the first-order oscillation of wind turbine blades and achieving the maintenance-free characteristic requirement for the lifespan of the liquid damper.

[0005] A second objective of the present invention is to provide a method for prefabricating a liquid damper for wind turbine blades with turbulent fluid.

[0006] A third objective of this invention is to provide a wind turbine blade.

[0007] The first objective of this invention is achieved through the following technical solution: a wind turbine blade liquid damper with a turbulent fluid, comprising an elongated tube, a turbulent fluid, and a damping fluid; the elongated tube is arranged in parallel at predetermined intervals on the inner surfaces of the SS and PS of the wind turbine blade, and located at the tip of the wind turbine blade; both ends of each elongated tube are connected to the leading edge and trailing edge of the wind turbine blade, respectively; the central axis of each elongated tube is perpendicular to the pitch shaft of the wind turbine blade; the turbulent fluid is embedded in the elongated tube and fixedly connected to the inner wall of the elongated tube, used to impede the flow of the damping fluid along the central axis of the elongated tube; the damping fluid is filled inside the elongated tube at a predetermined volume filling rate, so that the damping fluid is constrained to flow back and forth along the central axis of the elongated tube, and the direction of the centrifugal force of the blade is always perpendicular to the movement trajectory of the damping fluid.

[0008] Furthermore, the slender tube is a fiberglass tube, and the central axis of the cross-section along the length of the slender tube is a straight line or a curve.

[0009] Furthermore, the maximum diameter of the cross-section of the slender tube is less than 50 mm, and the cross-section of the slender tube is one of a circle, an ellipse, or a rectangle.

[0010] Furthermore, multiple slender tubes on the same PS inner surface or the same SS inner surface are arranged at intervals of 0.1m-1m along the spanwise direction of the wind turbine blade, and are located at a position at least 2 / 3 of the blade length away from the blade root.

[0011] Furthermore, the turbulent fluid is one or more of the following: a perforated baffle, a column-shaped protrusion, a mesh plate, a spiral strip, or a composite strip.

[0012] Furthermore, the damping fluid is one of silicone oil, water, or a saturated aqueous solution of calcium chloride, and the volume filling rate of the damping fluid is 10%–30%.

[0013] Furthermore, the total mass of the damping fluid is 0.1% to 1% of the total mass of the wind turbine blade.

[0014] The second objective of this invention is achieved through the following technical solution: a prefabrication method for a wind turbine blade liquid damper with turbulent fluid as described above, comprising the following steps:

[0015] S1. Prepare PS-shaped mold and SS-shaped mold to fit the blades of the damper mounting section.

[0016] S2. Place a layer of release cloth along the blade chord direction at the damper installation positions of the PS-shaped mold and the SS-shaped mold respectively.

[0017] S3. Hand lay down a base layer of glass cloth on the release cloth;

[0018] S4. Place a turbulent material on the base glass cloth layer, and arrange the turbulent material along the length of the airfoil profile line on the SS or PS surface.

[0019] S5. Hand lay several layers of glass cloth on top of the turbulent fluid to form a sealed, slender tubular container. Seal the turbulent fluid and adhere it to the inner wall of this container. At the same time, hand lay a damping fluid injection valve on the container and let it cure and solidify.

[0020] S6. After curing, a fiberglass liquid damper shell is formed. The shell encapsulates the turbulent fluid. At the same time, the liquid damper shell and the blade SS or PS surface have the same surface curvature. Then demolding is performed.

[0021] S7. After removing the release cloth and installing it on the wind turbine blade, add damping fluid to the housing of the liquid damper.

[0022] The third objective of the present invention is achieved by the following technical solution: a wind turbine blade, wherein the wind turbine blade has a built-in wind turbine blade liquid damper with turbulent fluid as described above.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] 1. The liquid damper of this invention employs a highly efficient liquid turbulence damping mechanism, featuring a simple structure, reliable performance, long lifespan, and maintenance-free operation. The use of a damper central axis structure perpendicular to the centrifugal force direction and a slender structure ensures excellent damping performance of the blades in any orientation during operation and shutdown. The adoption of slender tubes, low liquid filling ratio, long stroke, and the addition of turbulent fluid significantly improves damping efficiency.

[0025] 2. The damper of the present invention is maintenance-free, so the damper can be arranged inside the blade and placed as close as possible to the blade tip. Therefore, the applied liquid mass is minimized, the cost is minimized, and the first-order vibration of the blade can be effectively suppressed to achieve high-efficiency damping. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a wind turbine blade equipped with a linear liquid damper.

[0027] Figure 2This is a schematic diagram of a wind turbine blade equipped with an arc-shaped liquid damper. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments.

[0029] Example 1

[0030] See Figure 1 As shown, the linear liquid damper with turbulent fluid provided in this embodiment includes a linear slender tube 1, a turbulent fluid, and a damping fluid (not shown in the figure).

[0031] The straight, slender tube 1 is a fiberglass tube. Three straight, slender tubes 1 are arranged side-by-side at 0.1m intervals on the inner surface SS 2 and inner surface PS 3 of the wind turbine blade. The straight, slender tubes 1 on the inner surface PS 3 and inner surface SS 2 are arranged in pairs (not shown in the figure). The straight, slender tubes 1 are located at the tip of the wind turbine blade. Each straight, slender tube 1 is positioned along the blade chord 4. Both ends of each straight, slender tube 1 are connected to the leading edge 5 and trailing edge 6 of the wind turbine blade, respectively. The central axis of each straight, slender tube 1 is perpendicular to the pitch shaft 7 of the wind turbine blade. The turbulent fluid (not shown in the figure) is embedded within the straight, slender tube 1 and fixedly connected to the inner wall of the straight, slender tube 1. The turbulent fluid and the straight... There is no relative slippage between the slender tubes 1. This is used to impede the flow of damping fluid along the central axis of the straight slender tubes. The turbulent fluid (not shown in the figure) is one or more of the following: a perforated baffle, a column-shaped protrusion, a grid plate, a spiral strip, or a composite strip. The damping fluid is filled inside the straight slender tubes 1 at a preset volumetric filling rate, causing the damping fluid to be constrained and flow back and forth along the central axis of the straight slender tubes. The turbulent flow created by the turbulent fluid impedes the flow, absorbing kinetic energy and reducing vibration. The direction 8 of the blade's centrifugal force is always perpendicular to the damping fluid's trajectory 9. During impeller rotation, the liquid damper can provide good damping even when it is in any position within 360 degrees of the vertical plane. The total mass of the damping fluid is 0.1%–1% of the total mass of the wind turbine blade; the damping fluid is one of silicone oil, water, or a saturated aqueous solution of calcium chloride; and the volumetric filling rate of the damping fluid is 10%–30%.

[0032] Liquid dampers need to be environmentally adaptable, operating normally in cold environments within a temperature range of -40℃ to +50℃. Therefore, silicone oil or specific electrolyte solutions can achieve this. Silicone oil is a more ideal material, and different molecular weight silicone oils can be selected based on the design viscosity. A saturated aqueous solution of calcium chloride can also be used, but this electrolyte solution has corrosive and lightning strike characteristics as side effects. However, the disadvantage of silicone oil is its higher cost compared to calcium chloride solution. If calcium chloride solution is used, local lightning protection must be considered. Therefore, the damping fluid is one of silicone oil, water, or a saturated aqueous solution of calcium chloride, selected based on the wind turbine's operating environment. Silicone oil or a saturated aqueous solution of calcium chloride is used in cold regions, while water is sufficient in warm and tropical regions. Using inexpensive water eliminates the need to consider lightning protection.

[0033] Example 2

[0034] See Figure 2 As shown, the wind turbine blade liquid damper with turbulent fluid provided in this embodiment includes an arc-shaped slender tube 10, a turbulent fluid and a damping fluid (not shown in the figure).

[0035] The arc-shaped slender tube 10 is an arc-shaped flat tube with a rectangular cross-section and is made of fiberglass. Three arc-shaped slender tubes 10 are arranged side-by-side at 1m intervals on the inner surfaces SS 11 and PS 11 (not shown in the figure) of the wind turbine blade. The arc-shaped slender tubes on the PS and SS inner surfaces are arranged in pairs (not shown in the figure). The arc-shaped slender tubes 10 are located at the tip of the wind turbine blade. Each arc-shaped slender tube 10 is positioned along the airfoil profile 12 of the blade. Both ends of each arc-shaped slender tube 10 are connected to the leading edge 13 and trailing edge 14 of the wind turbine blade, respectively. The central axis of each arc-shaped slender tube 10 is perpendicular to the pitch shaft 15 of the wind turbine blade. The turbulent fluid (not shown in the figure) is embedded within the arc-shaped slender tube 10. It is fixedly connected to the inner wall of the arc-shaped slender tube 10. There is no relative slippage between the turbulent fluid and the straight slender tube. It is used to impede the flow of damping fluid along the central axis of the arc-shaped slender tube 10. The turbulent fluid (not shown in the figure) is an epoxy glass fiber mesh plate. The damping fluid is filled into the interior of the arc-shaped slender tube at a preset volume filling rate, so that the damping fluid is constrained in the slender tube 10 and flows back and forth along the central axis of the arc-shaped slender tube 10. The turbulence formed by the impediment effect of the turbulent fluid absorbs kinetic energy and reduces vibration. The direction of the centrifugal force 16 of the blade is always perpendicular to the movement track 17 of the damping fluid. During the rotation of the impeller, the liquid damper can play a good damping role when it is in any position of 360 degrees in the vertical plane. The total mass of the damping fluid is 0.1% to 1% of the total mass of the wind turbine blade; the damping fluid is one of silicone oil, water or calcium chloride saturated aqueous solution; and the volume filling rate of the damping fluid is 10% to 30%.

[0036] Liquid dampers need to be environmentally adaptable, operating normally in cold environments within a temperature range of -40℃ to +50℃. Therefore, silicone oil or specific electrolyte solutions can achieve this. Silicone oil is a more ideal material, and different molecular weight silicone oils can be selected based on the design viscosity. A saturated aqueous solution of calcium chloride can also be used, but this electrolyte solution has corrosive and lightning strike characteristics as side effects. However, the disadvantage of silicone oil is its higher cost compared to calcium chloride solution. If calcium chloride solution is used, local lightning protection must be considered. Therefore, the damping fluid is one of silicone oil, water, or a saturated aqueous solution of calcium chloride, selected based on the wind turbine's operating environment. Silicone oil or a saturated aqueous solution of calcium chloride is used in cold regions, while water is sufficient in warm and tropical regions. Using inexpensive water eliminates the need to consider lightning protection.

[0037] Example 3

[0038] This embodiment provides a prefabrication method for a wind turbine blade liquid damper with turbulent fluid as described in Embodiment 1 or 2, comprising the following steps:

[0039] S1. Prepare PS-shaped mold and SS-shaped mold to fit the blades of the damper mounting section.

[0040] S2. Place a layer of release cloth along the blade chord direction at the damper installation positions of the PS-shaped mold and the SS-shaped mold respectively.

[0041] S3. Hand lay down a base layer of glass cloth on the release cloth;

[0042] S4. Place a turbulent material on the base glass cloth layer, and arrange the turbulent material along the length of the airfoil profile line on the SS or PS surface.

[0043] S5. Hand lay several layers of glass cloth on top of the turbulent fluid to form a sealed, slender tubular container. Seal the turbulent fluid and adhere it to the inner wall of this container. At the same time, hand lay a damping fluid injection valve on the container and let it cure and solidify.

[0044] S6. After curing, a fiberglass liquid damper shell is formed. The shell encapsulates the turbulent fluid. At the same time, the liquid damper shell and the blade SS or PS surface have the same surface curvature. Then demolding is performed.

[0045] S7. After removing the release cloth and installing it on the wind turbine blade, add damping fluid to the housing of the liquid damper.

[0046] Example 4

[0047] This embodiment provides a wind turbine blade, which incorporates a wind turbine blade liquid damper with turbulent fluid as described in Embodiment 1 or 2. There is at least one liquid damper, located at least 2 / 3 of the blade length from the blade root. The central axis of each liquid damper is perpendicular to the blade's pitch axis. The two ends of the liquid damper are connected to the leading and trailing edges of the blade, suppressing vibrations in the blade's yaw direction. Planar curved dampers are installed inside the blade along the PS and SS inner surfaces, preferably in a paired arrangement. Multiple liquid dampers on the same PS or SS surface are preferably spaced 0.1m-1m apart along the blade spanwise. The total mass of damping fluid in the wind turbine blade is 0.1%-1% of the total blade mass.

[0048] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Therefore, any changes made in accordance with the shape and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for prefabricating a liquid damper for wind turbine blades with turbulent fluid, characterized in that: The wind turbine blade liquid damper includes a slender tube, a turbulent fluid, and a damping fluid; The slender tubes are arranged in parallel at predetermined intervals on the inner surfaces of the SS and PS of the wind turbine blade, located at the blade tip. Each slender tube is connected at its two ends to the leading and trailing edges of the wind turbine blade, respectively. The central axis of each slender tube is perpendicular to the pitch shaft of the wind turbine blade. The damping fluid is embedded within the slender tube and fixedly connected to its inner wall. It is used to impede the flow of damping fluid along the central axis of the slender tube. The damping fluid is filled into the interior of the slender tube at a predetermined volumetric filling rate, constraining the damping fluid to reciprocate along the central axis of the slender tube. The direction of the centrifugal force of the blade is always perpendicular to the trajectory of the damping fluid. This prefabrication method includes the following steps: S1. Prepare PS-shaped mold and SS-shaped mold to fit the blades of the damper mounting section. S2. Place a layer of release cloth along the blade chord direction at the damper installation positions of the PS-shaped mold and the SS-shaped mold respectively. S3. Hand lay down a base layer of glass cloth on the release cloth; S4. Place a turbulent material on the base glass cloth layer, and arrange the turbulent material along the length of the airfoil profile line on the SS or PS surface. S5. Hand lay several layers of glass cloth on top of the turbulent fluid to form a sealed, slender tubular container. Seal the turbulent fluid and adhere it to the inner wall of this container. At the same time, hand lay a damping fluid injection valve on the container and let it cure and solidify. S6. After curing, a fiberglass liquid damper shell is formed. The shell encapsulates the turbulent fluid. At the same time, the liquid damper shell and the blade SS or PS surface have the same surface curvature. Then demolding is performed. S7. After removing the release cloth and installing it on the wind turbine blade, add damping fluid to the housing of the liquid damper.

2. The prefabrication method for a wind turbine blade liquid damper with turbulent fluid as described in claim 1, characterized in that: The slender tube is a fiberglass tube, and the central axis of the cross-section along the length of the slender tube is a straight line or a curve.

3. The prefabrication method for a wind turbine blade liquid damper with turbulent fluid as described in claim 1, characterized in that: The maximum diameter of the slender tube is less than 50 mm, and the cross-section of the slender tube is one of a circle, an ellipse, or a rectangle.

4. The prefabrication method for a wind turbine blade liquid damper with turbulent fluid as described in claim 1, characterized in that: Multiple slender tubes are arranged at intervals of 0.1m-1m along the span of the wind turbine blade on the same PS inner surface or the same SS inner surface, and are located at a position at least 2 / 3 of the blade length away from the blade root.

5. The prefabrication method for a wind turbine blade liquid damper with turbulent fluid as described in claim 1, characterized in that: The turbulent material is one or more of the following: a perforated baffle, a column-shaped protrusion, a grid plate, a spiral strip, or a composite strip.

6. The prefabrication method for a wind turbine blade liquid damper with turbulent fluid as described in claim 1, characterized in that: The damping fluid is one of silicone oil, water, or a saturated aqueous solution of calcium chloride, and the volume filling rate of the damping fluid is 10%–30%.

7. The prefabrication method for a wind turbine blade liquid damper with turbulent fluid as described in claim 1, characterized in that: The total mass of the damping fluid is 0.1% to 1% of the total mass of the wind turbine blade.

8. A wind turbine blade, characterized in that, The wind turbine blade has a built-in wind turbine blade liquid damper prepared by the prefabrication method according to any one of claims 1 to 7.

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