Spring composite tuning liquid damper, using method and wind power blade

Abstract

The invention discloses a spring composite tuned liquid damper, a using method and a wind power blade. The spring composite tuned liquid damper comprises a damping tube, a spring, a throttling plate, a mandrel and a floating body. The damping tubes are symmetrically arranged and are connected together through the mandrel to form an annular tubular closed structure; a spring and a floating body are installed in an inner cavity of the end of each damping pipe, each damping pipe is filled with damping liquid, the damping liquid makes contact with the end face of the corresponding floating body, the two sides of the mandrel are connected with the floating bodies in series through the springs, the throttling plates are arranged in the inner cavities of the damping pipes, and the damping vibration attenuation effect is jointly achieved when the wind power blade moves. The liquid damper is used for vibration reduction of blades of a wind generating set, and the problems that an existing liquid damper is poor in damping vibration reduction effect and even cannot effectively reduce vibration under the large amplitude are solved; and meanwhile, the problem that coordination between low damping and high durability is difficult to achieve is solved, the low-frequency damping performance and the shock resistance are enhanced, and the wide-frequency-domain damping vibration attenuation performance is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind power blades, in particular to a spring composite tuned liquid damper for wind power blades, a use method and a wind power blade. BACKGROUND

[0002] In order to maximize the output of wind energy, the rotor diameter of wind turbines has increased exponentially over the past few decades, which in turn leads to severe vibration of the blades. Because the wind load acting on the twisted blade can be projected into two directions parallel and perpendicular to the rotation plane, the vibration direction of the blade can be the parallel pendulum vibration and the perpendicular flapping vibration to the rotation plane. The vibration of the blade in the direction perpendicular to the rotation plane is similar to the flutter phenomenon of the aircraft wing. Under normal operating conditions, the vibration of the blade in this direction is often accompanied by a large aerodynamic damping, which means that the response in this direction is mainly quasi-static. However, in extreme cases, the flapping vibration of the blade can cause collision between the blade and the tower, leading to dangerous failure of the wind turbine. At the same time, the pendulum vibration of the blade cannot be ignored, because the aerodynamic damping of the blade in this direction is almost negligible, which can cause large vibration of the blade. In some conditions, when the sum of the structural damping and the aerodynamic damping of the blade is negative, the pendulum mode of the blade can even experience aerodynamic elastic instability, which means that when the air force provides energy to the vibration system, the vibration of the blade will be amplified dramatically, which can cause the blade and the tower to produce a large displacement. When this displacement exceeds the maximum displacement that the structure can withstand, the entire wind turbine system may collapse. Therefore, improving the damping of the pendulum mode of the blade and effectively reducing the vibration become important considerations for protecting the blades of wind turbines from damage during design.

[0003] Structural vibration control technology can be divided into active control, semi-active control and passive control. The engineering field often reduces the vibration amplitude by installing active, semi-active and passive damping devices on the main structure. Among them, active control and semi-active control have high cost and complexity, and poor flexibility; passive control reduces the vibration response of the structure by changing the dynamic characteristics of the structure, without the need for external energy support, and has higher flexibility in practical application, and has greater potential in structural vibration control. In recent years, it has been used for vibration control in the field of wind power technology. Among them, the passive tuned liquid damper TLD relies on the shaking of the liquid to absorb and dissipate the vibration energy of the main structure, has the characteristics of low price, simple installation and simple operation and maintenance, and is favored by the industry.

[0004] Traditional TLDs have many shortcomings, such as a relatively small damping ratio provided by the viscosity of sloshing liquids and energy dissipation caused by laminar boundary layer flow, high sensitivity to excitation, and a narrow damping bandwidth. Furthermore, the dynamic characteristics of liquid dampers are much more complex than those of mass dampers, exhibiting highly nonlinear dynamic characteristics. This increases the difficulty of TLD modeling and dynamic analysis, making it difficult for the damper to achieve the desired performance. Improving damping performance is a pressing challenge and key issue that needs to be addressed in the field of wind power technology for liquid dampers. Existing technical documents are as follows:

[0005] Chinese utility model patent CN221628715U discloses a liquid damper that employs a water tank with multiple parallel and independent cavities. Liquid is injected into each cavity, and at least one water-blocking grid is installed within each cavity. This grid obstructs the liquid flow and generates vortices as the liquid passes through it, thus dissipating energy and creating fluid damping. However, this liquid damper structure does not consider the impact resistance of the internal liquid when blade loads are excessive, and it also fails to effectively improve the damping and vibration reduction performance in the yaw direction under large blade amplitudes.

[0006] Chinese invention patent application CN116044649A discloses a liquid damper for wind turbine blades, which includes a slender tube and a damping fluid. The slender tube is arranged in parallel on the inner surface of the SS and the inner surface of the PS of the wind turbine blade at multiple predetermined intervals. By bending the slender tube, liquid turbulence is created to absorb vibration energy. However, the above structure increases the manufacturing difficulty of the blade and makes implementation difficult. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by providing a spring-composite tuned liquid damper for wind turbine blades, its usage method, and the wind turbine blade itself. This invention solves the problem of poor damping and vibration reduction effect of current liquid dampers, which are even unable to effectively reduce vibration under large blade amplitude. It achieves synergistic coordination between low damping and high durability, significantly improves the damping performance in the blade's oscillation direction, and provides additional support force to ensure the stability of the wind turbine blade structure.

[0008] To achieve the above objectives, the technical solution provided by this invention is as follows: a spring-composite tuned liquid damper for wind turbine blades, comprising a damping tube, a spring, a throttling plate, a spindle, and a float; the damping tubes are symmetrically arranged and connected together by the spindle to form an annular tubular closed structure; each damping tube has a spring and a float installed in its end cavity, each damping tube is filled with damping fluid and the damping fluid is in contact with the end face of the float; both sides of the spindle are connected in series with the float via springs; the throttling plate is disposed in the inner cavity of the damping tube; the damping tube, damping fluid, spring, throttling plate, spindle, and float together form a damping and vibration reduction effect when the wind turbine blade moves.

[0009] Furthermore, the damping tube is a U-shaped damping tube, which includes a vertical pipe and a horizontal pipe connected between the vertical pipes.

[0010] Furthermore, the throttling plate is fixed on the upper and lower sides of the inner cavity of the horizontal pipe and located at the midpoint of the length direction of the horizontal pipe.

[0011] Furthermore, there are two damping tubes, and each of the two open ends of the damping tube is equipped with a spring and a float.

[0012] Furthermore, the cross-section of the damping tube is processed into a rectangular shape, an arc shape, or a shape that conforms to the inner surface of the wind turbine blade, and the outer wall of the damping tube is provided with sealant.

[0013] Furthermore, a mandrel connection hole is provided at the end of the damping tube, and the mandrel and the damping tube are fixedly connected through the mandrel connection hole.

[0014] Furthermore, the spring-loaded composite tuned liquid damper includes a conformal cavity, which is sleeved on the outside of the annular tubular closed structure, and the conformal cavity conforms to the inner surface of the wind turbine blade.

[0015] Furthermore, the spring-loaded composite tuned liquid damper is installed on the web of the wind turbine blade. The web has a web hole through which the spring-loaded composite tuned liquid damper passes. Structural adhesive or fiberglass cloth is provided at the connection between the web hole and the spring-loaded composite tuned liquid damper.

[0016] A method of using the above-described spring-triggered composite tuned liquid damper includes the following steps:

[0017] S1. Two U-shaped damping tubes are arranged symmetrically, one above the other, as an upper damping tube and the other below. The open ends of the upper and lower damping tubes are connected together by a mandrel to form a closed annular tubular structure. The open ends of the upper and lower damping tubes are provided with mandrel connection holes. The upper and lower damping tubes are fixedly connected to the mandrel through the mandrel connection holes. The connection methods include welding, threaded connection and interference fit.

[0018] S2. A spring and a float are installed in the open end of each upper and lower damping tube. The two ends of the spring are fixedly connected in series with the mandrel and the float, respectively. That is, in each open end, the spring in the upper damping tube and the spring in the lower damping tube are symmetrically placed on the upper and lower sides of the mandrel flange. A throttling plate is added to the middle of the closed end of the lower and upper damping tubes and filled with damping fluid. The floats in the upper and lower damping tubes are in contact with the damping fluid.

[0019] S3. Two web holes are made in the web of the wind turbine blade. The cross-sectional area of ​​the web holes is the same as that of the horizontal pipes of the upper and lower damping tubes. The upper and lower damping tubes are passed through the two web holes respectively. Structural adhesive or hand lay-up fiberglass cloth is used at the junction of the web and the outer surface of the damping tube to ensure the reliability of the damper fixing.

[0020] S4. A conformal cavity that conforms to the inner surface of the wind turbine blade is fitted outside the annular tubular closed structure. This facilitates installation within the inner cavity of the wind turbine blade as the membrane is attached, and serves for sealing and corrosion protection.

[0021] S5. The resonant frequency is adjusted by changing the volume of damping fluid inside the spring-composite tuned liquid damper; the damping and vibration reduction capacity is adjusted by changing the stiffness of the spring and the cross-sectional area of ​​the throttling plate; when the wind turbine blade rotates and its tip points downward, the internal structure of the lower damping tube plays the main role in damping and vibration reduction, and when its tip points upward, the internal structure of the upper damping tube plays the main role in damping and vibration reduction. In other cases, the internal structures of the upper and lower damping tubes work together to play a damping role.

[0022] A wind turbine blade, wherein the aforementioned spring-composite tuned liquid damper is installed in the inner cavity of the wind turbine blade.

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

[0024] 1. The damper of this invention achieves a damping effect through the combined action of a damping tube, a throttling plate, and a spring, significantly improving the damping performance in the blade oscillation direction. Tests show that the damping ratio in the blade oscillation direction can be increased by at least 0.4%. By changing the volume of the damping fluid, the resonant frequency can be adjusted; by changing the spring stiffness and the cross-sectional area of ​​the throttling plate, the damping and vibration reduction capability of the damper can be adjusted. This damper enhances low-frequency damping performance and impact resistance, achieving improved damping performance over a wide frequency range.

[0025] 2. The damper of the present invention can prevent overload. When the load is too large, the spring provides additional support force to ensure the stability of the structure and play a protective role, thus improving the shortcomings of the traditional TLD in terms of poor overload protection.

[0026] 3. The damper of the present invention has an integrated closed structure, and its manufacturing process is simple, low-cost, and easy to install; at the same time, it can be disassembled without disassembly, which extends the life of the shock absorber and enhances the damping and vibration reduction effect, achieving synergistic coordination between low damping and high durability, and also greatly saving maintenance costs. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a spring-loaded composite tuned liquid damper.

[0028] Figure 2This is a cross-sectional view of the spring-loaded composite tuned liquid damper.

[0029] Figure 3 This is one of the schematic diagrams of the installation structure of a spring-loaded composite tuned liquid damper.

[0030] Figure 4 This is the second schematic diagram of the installation structure of a spring-loaded composite tuned liquid damper.

[0031] Figure 5 This is the third schematic diagram of the installation structure of a spring-loaded composite tuned liquid damper.

[0032] In the diagram: 1-Lower damping tube; 2-Lower throttle plate; 3-Lower damping tube inner cavity; 4-First lower float; 5-Second lower float; 6-First lower spring; 7-Second lower spring; 8-First mandrel; 9-Second mandrel; 10-First upper spring A; 11-Second upper spring; 12-First upper float A; 13-Second upper float; 14-Upper damping tube; 15-Upper damping tube inner cavity; 16-Upper throttle plate; 17-First mandrel connecting hole; 18-Second mandrel connecting hole; 19-Blade web; 20-Lower damping tube structural adhesive; 21-Upper damping tube structural adhesive; 22-Lower web hole; 23-Upper web hole; 24-First conformal cavity structural adhesive; 25-Second conformal cavity structural adhesive; 26-Conformal cavity; 27-Wind turbine blade. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments.

[0034] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0035] Furthermore, the orientations or positional relationships used in any of the technical solutions disclosed in this invention above to indicate positional relationships, such as "longitudinal," "lateral," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing this patent. They 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 this patent. In addition, unless otherwise stated, the terms used to indicate shape in any of the technical solutions disclosed in this invention above include shapes that are similar to, close to, or approximate with it.

[0036] Example 1

[0037] See Figures 1 to 3 As shown, the spring-loaded composite tuned liquid damper provided in this embodiment includes a lower damping tube 1 and an upper damping tube 14. The internal structures of the upper and lower damping tubes are the same, both being U-shaped damping tubes, and they are symmetrically distributed at the top and bottom. Both the upper and lower damping tubes include a vertical pipe and a horizontal pipe connecting the vertical pipes. The lower damping tube 1 and the upper damping tube 14 are fixedly connected to the first mandrel 8 and the second mandrel 9, respectively. The two ends of the upper damping tube 14 are provided with a first mandrel connection hole 17 and a second mandrel connection hole 18. The two ends of the lower damping tube 1 are also provided with mandrel connection holes (not shown in the figure). The two mandrels are fixedly connected to the upper and lower damping tubes through the mandrel connection holes. The connection can be made by welding, threaded connection, or interference fit, forming an annular tubular closed structure. To prevent the damping fluid inside the upper and lower damping tubes from leaking, a structural adhesive or waterproof adhesive with a thickness of about 2 mm is evenly applied to the outer wall.

[0038] The first lower spring 6 is welded and connected in series with the first spindle 8 and the first lower float 4, the second lower spring 7 is welded and connected in series with the second spindle 9 and the second lower float 5, the first upper spring 10 is welded and connected in series with the first spindle 8 and the first upper float 12, and the second upper spring 11 is welded and connected in series with the second spindle 9 and the second upper float 13. The first lower spring 6 and the first upper spring 10 are symmetrically placed on the upper and lower sides of the flange of the first spindle 8, and the second lower spring 7 and the second upper spring 11 are symmetrically placed on the upper and lower sides of the flange of the second spindle 9. The first lower spring 6, the second lower spring 7, the first upper spring 10, and the second upper spring 11 are metal springs or polymer material springs.

[0039] Lower throttling plate 2 and upper throttling plate 16 are added to the horizontal pipes of the lower damping tube 1 and upper damping tube 14. The lower throttling plate 2 and upper throttling plate 16 are fixedly bonded to the upper and lower sides of the inner cavity of the horizontal pipe and located at the midpoint of the length of the horizontal pipe. The damping and vibration reduction capacity of the damper can be adjusted by adjusting its cross-sectional area. The lower end face of the first lower float 4 and the second lower float 5 is in contact with the damping fluid in the inner cavity 3 of the lower damping tube, and the lower end face of the first upper float 12 and the second upper float 13 is in contact with the damping fluid in the inner cavity 15 of the upper damping tube. The resonant frequency can be adjusted by changing the volume of damping fluid in the inner cavity 3 of the lower damping tube and the inner cavity 15 of the upper damping tube.

[0040] The spring-loaded composite tuned liquid damper is installed on the blade web 19 of the wind turbine blade 27. The blade web 19 has a lower web hole 22 and an upper web hole 23 through which the spring-loaded composite tuned liquid damper passes. The lower web hole 22 is provided with lower damping tube structural adhesive 20 at the connection between it and the lower damping tube 1, and the upper web hole 23 is provided with upper damping tube structural adhesive 21 at the connection between it and the upper damping tube 14.

[0041] Example 2

[0042] See Figures 4 to 5 As shown, unlike Embodiment 1, the spring-loaded composite tuned liquid damper provided in this embodiment includes a conformal cavity 26. The conformal cavity 26 is sleeved on the outside of the annular tubular closed structure. The conformal cavity 26 conforms to the inner surface of the wind turbine blade 27. The connection between the conformal cavity 26 and the two sides of the blade web 19 is provided with a first conformal cavity structural adhesive 24 and a second conformal cavity structural adhesive 25, which facilitates installation in the inner cavity of the wind turbine blade 27 as the wind turbine blade 27 is laminated, and is used for sealing and corrosion protection.

[0043] Example 3

[0044] A method of using the spring-composite tuned liquid damper according to Embodiment 1 or 2 includes the following steps:

[0045] S1. Two U-shaped damping tubes are arranged symmetrically on top and bottom, namely an upper damping tube and a lower damping tube, and the open ends of the upper damping tube and the lower damping tube are connected together by a first mandrel and a second mandrel to form an annular tubular closed structure; wherein, the open ends of the upper damping tube and the lower damping tube are provided with mandrel connection holes, and the upper damping tube and the lower damping tube are fixedly connected to the mandrel through the mandrel connection holes, and the connection methods include welding, threaded connection and interference fit;

[0046] S2. A spring and a float are installed in the open end of each upper and lower damping tube. The two ends of the spring are fixedly connected in series with the mandrel and the float, respectively. That is, in each open end, the spring in the upper damping tube and the spring in the lower damping tube are symmetrically placed on the upper and lower sides of the mandrel flange. A throttling plate is added to the middle of the closed end of the lower and upper damping tubes and filled with damping fluid. The floats in the upper and lower damping tubes are in contact with the damping fluid.

[0047] S3. Two web holes are made in the web of the wind turbine blade. The cross-sectional area of ​​the web holes is the same as that of the horizontal pipes of the upper and lower damping tubes. The upper and lower damping tubes are passed through the two web holes respectively. Structural adhesive or hand lay-up fiberglass cloth is used at the junction of the web and the outer surface of the damping tube to ensure the reliability of the damper fixing.

[0048] Preferably, a conformal cavity that follows the shape of the inner surface of the wind turbine blade is fitted outside the annular tubular closed structure, which is convenient to be installed in the inner cavity of the wind turbine blade when the film is closed, and is used for sealing and corrosion protection.

[0049] S4. The resonant frequency is adjusted by changing the volume of damping fluid inside the spring-composite tuned liquid damper; the damping and vibration reduction capacity is adjusted by changing the stiffness of the spring and the cross-sectional area of ​​the throttling plate; when the wind turbine blade rotates and its tip points downward, the internal structure of the lower damping tube plays the main role in damping and vibration reduction, and when its tip points upward, the internal structure of the upper damping tube plays the main role in damping and vibration reduction. In other cases, the internal structures of the upper and lower damping tubes work together to play a damping role.

[0050] 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 spring-loaded composite tuned liquid damper for wind turbine blades, characterized in that: The system includes damping tubes, springs, throttle plates, mandrels, and floats. The damping tubes are symmetrically arranged and connected together by the mandrel to form a closed annular tubular structure. Each damping tube has a spring and a float installed in its end cavity. Each damping tube is filled with damping fluid, and the damping fluid is in contact with the end face of the float. Both sides of the mandrel are connected in series with the float via springs. The throttle plate is set in the inner cavity of the damping tube. The damping tubes, damping fluid, springs, throttle plates, mandrels, and floats work together to form a damping and vibration reduction effect when the wind turbine blades move.

2. The spring-composite tuned liquid damper for wind turbine blades according to claim 1, characterized in that: The damping tube is a U-shaped damping tube, which includes a vertical pipe and a horizontal pipe connected between the vertical pipes.

3. The spring-composite tuned liquid damper for wind turbine blades according to claim 2, characterized in that: The throttling plate is fixed on the upper and lower sides of the inner cavity of the horizontal pipe and is located at the midpoint of the length of the horizontal pipe.

4. A spring-composite tuned liquid damper for wind turbine blades according to claim 2, characterized in that: There are two damping tubes, and each of the two open ends of the damping tube is equipped with a spring and a float.

5. The spring-composite tuned liquid damper for wind turbine blades according to claim 1, characterized in that: The damping tube has a cross-section that is rectangular, arc-shaped, or conforms to the shape of the inner surface of the wind turbine blade, and the outer wall of the damping tube is provided with sealant.

6. The spring-composite tuned liquid damper for wind turbine blades according to claim 1, characterized in that: The damping tube has a mandrel connection hole at its end, and the mandrel and the damping tube are fixedly connected through the mandrel connection hole.

7. The spring-composite tuned liquid damper for wind turbine blades according to claim 1, characterized in that: It includes a conformal cavity, which is fitted on the outside of an annular tubular closed structure, and the conformal cavity conforms to the inner surface of the wind turbine blade.

8. The spring-loaded composite tuned liquid damper for wind turbine blades according to claim 1, characterized in that: The spring-loaded composite tuned liquid damper is installed on the web of the wind turbine blade. The web has a web hole through which the spring-loaded composite tuned liquid damper passes. Structural adhesive or fiberglass cloth is provided at the connection between the web hole and the spring-loaded composite tuned liquid damper.

9. A method of using the spring-composite tuned liquid damper according to any one of claims 1-8, characterized in that, Includes the following steps: S1. Two U-shaped damping tubes are arranged symmetrically, one above the other, as an upper damping tube and the other below. The open ends of the upper and lower damping tubes are connected together by a mandrel to form a closed annular tubular structure. The open ends of the upper and lower damping tubes are provided with mandrel connection holes. The upper and lower damping tubes are fixedly connected to the mandrel through the mandrel connection holes. The connection methods include welding, threaded connection and interference fit. S2. A spring and a float are installed in the open end of each upper and lower damping tube. The two ends of the spring are fixedly connected in series with the mandrel and the float, respectively. That is, in each open end, the spring in the upper damping tube and the spring in the lower damping tube are symmetrically placed on the upper and lower sides of the mandrel flange. A throttling plate is added to the middle of the closed end of the lower and upper damping tubes and filled with damping fluid. The floats in the upper and lower damping tubes are in contact with the damping fluid. S3. Two web holes are made in the web of the wind turbine blade. The cross-sectional area of ​​the web holes is the same as that of the horizontal pipes of the upper and lower damping tubes. The upper and lower damping tubes are passed through the two web holes respectively. Structural adhesive or hand lay-up fiberglass cloth is used at the junction of the web and the outer surface of the damping tube to ensure the reliability of the damper fixing. S4. A conformal cavity that conforms to the inner surface of the wind turbine blade is fitted outside the annular tubular closed structure. This facilitates installation within the inner cavity of the wind turbine blade as the membrane is attached, and serves for sealing and corrosion protection. S5. The resonant frequency is adjusted by changing the volume of damping fluid inside the spring-composite tuned liquid damper; the damping and vibration reduction capacity is adjusted by changing the stiffness of the spring and the cross-sectional area of ​​the throttling plate; when the wind turbine blade rotates and its tip points downward, the internal structure of the lower damping tube plays the main role in damping and vibration reduction, and when its tip points upward, the internal structure of the upper damping tube plays the main role in damping and vibration reduction. In other cases, the internal structures of the upper and lower damping tubes work together to play a damping role.

10. A wind turbine blade, characterized in that, The inner cavity of the wind turbine blade is equipped with a spring-composite tuned liquid damper as described in any one of claims 1-8.

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