Multi-tuning liquid damper for controlling cross-wind multi-mode vibration of floating fan tower drum

Abstract

The invention discloses a multi-tuned liquid damper for cross-wind multi-modal vibration control of a floating fan tower drum, which comprises a floating fan tower drum, and a plurality of liquid dampers are fixedly connected along the vertical direction of the floating fan tower drum; each liquid damper comprises a connecting piece, an external cavity fixedly connected with the connecting piece and internal liquid arranged in the external cavity; through liquid damper distribution multipoint cooperative tuning, each damper performs effective energy consumption on main modal response of the position where the damper is located, the amplitude of a multi-order vibration mode is remarkably restrained, and the vibration reduction effect of the whole structure is improved. According to the invention, accurate tuning and efficient energy consumption of a plurality of key vibration modes are realized, the modal amplitude of each order is effectively reduced, and the resonance phenomenon is inhibited, so that the anti-vibration performance and safety of the whole tower drum are improved, the service life of a fan system is prolonged, and the maintenance and repair cost is reduced.

Description

Technical Field

[0001] This invention relates to the technical field of floating wind turbines, and particularly to a multi-tuned liquid damper for crosswind multimodal vibration control of floating wind turbine towers. Background Technology

[0002] The most common type of liquid damper is the tuned liquid damper (TLD), which works by using the inertial motion of liquid within a cavity to dissipate structural vibration energy, thereby reducing structural vibration. TLDs are typically installed at the top of the structure or other specific locations and are tuned to the structure's primary vibration modes (such as the first-order frequency). These devices are widely used in fixed high-rise buildings, bridges, and some wind turbine tower vibration reduction applications. Numerous domestic and international publications and patents have reported the effectiveness of TLDs in structural control. For example, in the wind and seismic design of high-rise buildings, TLDs can significantly reduce the top response of the structure, extend its service life, and reduce maintenance costs.

[0003] Current research on multimodal vibration control mainly focuses on the following areas: 1. Single Liquid Damper Tuning: A single TLD is commonly used, installed at the top of the tower, primarily for vibration control of the first mode. This method is simple in structure and easy to tune, but limited by the resonant frequency characteristics of the liquid damper, it can only effectively reduce the amplitude of one mode, with limited control capability for other modes. Numerous experimental and numerical studies have shown that the effectiveness of a single TLD in controlling higher-order modes of vibration is significantly reduced, and it may even induce negative effects such as coupled resonance or amplification of local responses under multi-mode vibration conditions.

[0004] 2. Multi-degree-of-freedom liquid damper design: Some studies have attempted to design liquid damping cavities as multi-degree-of-freedom systems, utilizing different cavities or multiple layers of liquid to achieve responses at multiple frequencies. However, due to limitations in structural complexity and tuning accuracy, practical engineering applications are limited, and maintenance is difficult, costly, and the damping effect is not easily stabilized.

[0005] 3. Other types of dampers (such as tuned mass dampers (TMDs), untuned dampers, etc.): Tuned mass dampers (TMDs) dissipate vibration energy through a combination of counterweights and springs / damping elements. They are also primarily designed for a single mode, and their installation and maintenance are difficult in large, flexible structures like floating wind turbines, resulting in insufficient long-term reliability. While untuned dampers can provide a broad spectrum of energy dissipation, their vibration control efficiency is low, and they cannot be precisely tuned for specific modes.

[0006] To address the limitations of existing technologies, the industry has gradually recognized that multimodal vibration control must move beyond the traditional approach of single-tuning and single-point energy dissipation, and achieve coordinated energy dissipation and precise tuning of multiple key vibration modes. This is particularly relevant in highly flexible, large-scale structures like floating wind turbine towers, where the natural frequencies of the structure are widely distributed, multiple vibration modes may be activated by environmental loads, and their spatial distribution of vibration response varies significantly. For example, the first-order vibration mode typically exhibits overall bending, with the largest response amplitude at the top of the tower, while the second and third-order modes show response peaks in the middle or at three-quarters of the structure's height. A single damper installed at the top of the tower can only effectively control the first-order mode, with limited effect on higher-order modes, and may even increase the local response.

[0007] In summary, existing technologies mostly employ a single tuned liquid damper installed at the top of the tower, which can only effectively control the first-order mode and has no significant suppression effect on higher-order mode vibrations. Some multi-degree-of-freedom or distributed damping schemes are limited in practical application value due to structural complexity, tuning accuracy, and maintenance difficulty. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a multi-tuned liquid damper for crosswind multimodal vibration control of floating wind turbine towers. By rationally designing the liquid mass, liquid level, and cavity geometry parameters, it achieves precise tuning and efficient energy dissipation of multiple key vibration modes, effectively reducing the amplitude of each mode and suppressing resonance phenomena. This improves the overall vibration resistance and safety of the tower, extends the service life of the wind turbine system, and reduces maintenance and repair costs. To achieve the above-mentioned objectives and other advantages of the present invention, a multi-tuned liquid damper for crosswind multimodal vibration control of floating wind turbine towers is provided, comprising: A floating wind turbine tower, with multiple liquid dampers fixedly connected along the vertical direction of the floating wind turbine tower; Each of the liquid dampers includes a connector, an external cavity fixed to the connector, and an internal liquid disposed in the external cavity; By distributing liquid dampers at multiple points for coordinated tuning, each damper can effectively dissipate energy in the main modal response at its location, significantly suppressing the amplitude of multiple vibration modes and improving the overall vibration reduction effect of the structure.

[0009] Preferably, the parameters of each liquid damper are precisely tuned according to the frequency and response characteristics of each mode of the floating wind turbine tower, so that its main energy dissipation frequency corresponds to the key vibration mode of the structure.

[0010] Preferably, the parameters include the dimensions of the external cavity, the mass of the internal liquid, and the depth of the internal liquid.

[0011] Preferably, when modal analysis is performed on the floating wind turbine tower, a liquid damper is arranged at the point of maximum modal response.

[0012] Preferably, liquid dampers are fixed to the top, middle and three-quarters of the height of the floating wind turbine tower.

[0013] Preferably, the internal liquid is water, oil, or a damping fluid with good flow properties.

[0014] Compared with existing technologies, this technology enables multimodal vibration coordinated control. 1. This invention adopts a distributed multi-tuned liquid damper design. By arranging multiple dampers at different heights of the tower and tuning them to the key modal frequencies, it can synergistically suppress multiple vibration modes of the structure, significantly improve the overall vibration reduction effect, and break through the limitation of traditional single TLDs that can only control a single mode.

[0015] 2. Optimized distribution and high energy efficiency: Based on the spatial distribution law of structural modal response, dampers are arranged at the peak of each modal response, which effectively improves the energy efficiency of each damper, maximizes the vibration control effect, and avoids the risk of local response amplification and resonance.

[0016] 3. Simple structure, easy to implement and maintain: This invention uses a liquid damper, which has a simple structure, requires no complex mechanical components, and is easy to integrate into the tower structure. The damper is easy to tune and maintain, which helps to reduce operating and maintenance costs.

[0017] 4. Strong adaptability and versatility: The distributed multi-tuning scheme can flexibly adjust the number of dampers, the arrangement height and the tuning parameters according to different tower structures, wind turbine capacity and actual working conditions, and has good engineering applicability and promotion value.

[0018] 5. Significantly improves structural safety and service life: Numerical simulation and physical model tests prove that the distributed multi-tuned liquid damper can effectively reduce the vibration response of floating wind turbine towers in all modes, improve the structural vibration resistance, extend service life, and ensure the safe and reliable operation of the wind turbine. Attached Figure Description

[0019] Figure 1 A schematic diagram of the floating wind turbine tower structure of the multi-tuned liquid damper for crosswind multimodal vibration control of the floating wind turbine tower according to the present invention; Figure 2 A cross-sectional view of the liquid damper structure of the multi-tuned liquid damper for crosswind multimodal vibration control of the floating wind turbine tower according to the present invention; Figure 3This is a schematic diagram showing the distribution of multiple dampers in the multi-tuned liquid damper for crosswind multimodal vibration control of a floating wind turbine tower according to the present invention. Detailed Embodiments 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.

[0020] The invention aims to solve the problem of multimodal vibration in floating wind turbine towers under crosswind loads. Due to the high flexibility of the floating wind turbine tower structure and the complex working environment, external disturbances such as wind, waves, and currents often induce multiple vibration modes in the tower. In particular, crosswinds can lead to low-order and high-order resonance phenomena, causing structural fatigue damage and safety hazards, and affecting the normal operation and service life of the wind turbine.

[0021] This invention achieves precise tuning and efficient energy dissipation of multiple key vibration modes through the rational design of liquid mass, liquid level, and cavity geometry parameters. This effectively reduces the amplitude of each mode and suppresses resonance, thereby improving the overall vibration resistance and safety of the tower, extending the service life of the wind turbine system, and reducing maintenance and repair costs. A distributed multi-tunable liquid damper design is presented, with tuning parameters tailored to each key vibration mode, and arranged at the top, three-quarters height, and middle of the tower to achieve synchronous control of multi-mode vibration. This scheme features a rational structure, precise tuning, and high energy efficiency, significantly improving the vibration resistance and service life of floating wind turbine towers, and has significant engineering application value and promising prospects for widespread application.

[0022] Reference Figure 1-2 A multi-tuned liquid damper for crosswind multimodal vibration control of floating wind turbine towers, including: Multiple liquid dampers are arranged at different heights within the floating wind turbine tower, including the top, three-quarters height, and middle sections. The parameters of each damper are precisely tuned according to the frequency and response characteristics of each mode of the tower, ensuring that its primary energy-dissipating frequency corresponds to the key vibration mode of the structure. Through distributed multi-point coordinated tuning, each damper can effectively dissipate energy in the primary modal response at its location, significantly suppressing the amplitude of multiple vibration modes and improving the overall vibration reduction effect of the structure. The parameters include cavity size, liquid mass, and liquid depth.

[0023] Reference Figure 2-3As shown, each liquid damper includes a sealed cavity 1, an internal liquid 4, a fixed support 3, and a connector 2. During structural vibration, the liquid sloshes within the cavity 1. The relative motion between the liquid and the cavity wall absorbs and dissipates structural vibration energy through the inertia and viscosity of the liquid. The cavity size, liquid type, and depth of the liquid damper can be designed and optimized according to the specific parameters and modal response characteristics of the floating wind turbine tower, ensuring that the natural frequency of the liquid damper is highly consistent with the target modal frequency, thereby maximizing energy dissipation. The sealed cavity 1 is made of high-strength metal or composite material. The internal liquid 4 can be water, oil, or a high-efficiency damping fluid. The damper is securely fixed to the tower structure via the connector 2, ensuring safe operation.

[0024] Multiple liquid dampers are distributed at different heights within the tower. The parameters of each damper are independently tuned to suit the target mode.

[0025] In the specific implementation process, the engineering workflow is as follows: 1. Perform modal analysis on the floating wind turbine tower to determine the frequency and spatial distribution of the main vibration modes. The frequencies of the vibration modes are the first three modes in the crosswind direction of the tower. 2. Based on the peak response locations of each mode, determine the arrangement height and location of the liquid damper. Usually, the damper is placed at the location of the maximum modal response, typically at the top, 3 / 4, and middle of the tower. This can effectively generate control bending moment to reduce the bending moment at the bottom of the tower. 3. For each critical mode (three levels forward of crosswind in the tower), the water in the sloshing damper is generally taken as one percent of the mode mass, and is calculated according to the formula. Determine the depth of the liquid in the tank, where L is the length of the tank (determined based on the tower dimensions). The width of the tank is determined by mass, because once L and the liquid depth are determined, the width can be calculated based on mass, thus matching its natural frequency with the target modal frequency. 4. Securely install the liquid damper at the designated height on the tower and firmly connect it to the structure using connectors to ensure safety and stability during operation; 5. During wind turbine operation, the liquid damper continuously absorbs and dissipates the tower's vibration energy through the sloshing of its internal liquid, achieving synergistic vibration reduction across multiple modes. The liquid damper absorbs structural vibration energy, continuously exerting a multi-mode vibration reduction effect. Regularly check the damper's sealing and liquid condition to ensure long-term stable operation.

[0026] The distributed multi-tuned liquid damper system of this invention has advantages such as simple structure, flexible tuning, and easy installation and maintenance. The damper cavity can be made of metal or high-strength composite material, and the liquid is generally water, oil, or a damping fluid with good flow properties. The system can flexibly adjust the number, arrangement, and parameter settings of the dampers according to the wind turbine capacity, tower structure size, and actual operating conditions to meet different engineering needs. Through this invention, the modal vibration response of floating wind turbine towers under multi-source environmental loads can be significantly suppressed, structural fatigue damage is reduced, service life is extended, and operational safety and reliability are significantly improved. Numerical simulation and physical model test verification show that this distributed multi-tuned liquid damper scheme can be widely applied to the multimodal vibration control of large flexible structures such as floating wind turbines, offshore platforms, and high-rise towers, and has good engineering application value and promotion prospects. Those skilled in the art can, based on the above description, use conventional structural modal analysis and liquid damper design methods, combined with actual engineering parameters, to complete the design, installation, and commissioning of this invention, and achieve efficient and coordinated control of multimodal vibration of floating wind turbine towers. Distributed multi-tuned liquid dampers can synergistically suppress multi-modal vibrations of floating wind turbine towers, significantly improving structural safety and service life. This implementation method has a simple structure, flexible parameter adjustment, convenient installation and maintenance, and is easy to promote and apply in practical engineering.

[0027] The number of devices and processing scale described herein are for simplification of the invention. Applications, modifications, and variations of this invention will be readily apparent to those skilled in the art. Although embodiments of the invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for this invention, and further modifications can be readily implemented by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, this invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A multi-tuned liquid damper for crosswind multi-mode vibration control of a floating wind turbine tower, characterized in that, include: A floating wind turbine tower, with multiple liquid dampers fixedly connected along the vertical direction of the floating wind turbine tower; Each of the liquid dampers includes a connector, an external cavity fixed to the connector, and an internal liquid disposed in the external cavity; By distributing liquid dampers at multiple points for coordinated tuning, each damper can effectively dissipate energy in the main modal response at its location, significantly suppressing the amplitude of multiple vibration modes and improving the overall vibration reduction effect of the structure.

2. The multi-tuned liquid damper for crosswind multi-mode vibration control of floating wind turbine towers as described in claim 1, characterized in that, The parameters of each liquid damper are precisely tuned according to the frequency and response characteristics of each mode of the floating wind turbine tower, so that its main energy dissipation frequency corresponds to the key vibration mode of the structure.

3. The multi-tuned liquid damper for crosswind multi-mode vibration control of floating wind turbine towers as described in claim 2, characterized in that, The parameters include the dimensions of the external cavity, the mass of the internal liquid, and the depth of the internal liquid.

4. The multi-tuned liquid damper for crosswind multi-mode vibration control of floating wind turbine towers as described in claim 1, characterized in that, When performing modal analysis on the floating wind turbine tower, a liquid damper is placed at the point of maximum modal response.

5. The multi-tuned liquid damper for crosswind multi-mode vibration control of floating wind turbine towers as described in claim 4, characterized in that, Liquid dampers are fixed to the top, middle and three-quarters of the height of the floating wind turbine tower.

6. The multi-tuned liquid damper for crosswind multi-mode vibration control of floating wind turbine towers as described in claim 1, characterized in that, The internal liquid is water, oil, or a damping fluid with good flow properties.

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