Offshore wind turbine and four-buoy semi-submersible floating body platform and low-frequency tuning liquid column damper thereof

Abstract

The low-frequency tuning liquid column damper comprises three horizontal tuning liquid columns which are annularly and evenly distributed, and vertical tuning liquid columns are arranged at the outward ends of the three horizontal tuning liquid columns in the radial direction correspondingly; the horizontal tuning liquid column comprises a horizontal snakelike pipeline, and a first horizontal pipe section and a second horizontal pipe section are arranged at the two ends of the horizontal snakelike pipeline respectively; the vertical tuning liquid column comprises a vertical snakelike pipeline, and a vertical pipe section is arranged at the lower end of the vertical snakelike pipeline; the horizontal tuning liquid column and the vertical tuning liquid column are connected through the adjacent first horizontal pipe section and vertical pipe section; the three adjacent second horizontal pipe sections among the three horizontal tuning liquid columns are communicated with one another; a damping valve is arranged in the second horizontal pipe section, and the horizontal tuning liquid column and the vertical tuning liquid column are filled with damping liquid. The utility model further discloses a four-buoy semi-submersible type floating body platform and an offshore wind turbine, and the four-buoy semi-submersible type floating body platform and the offshore wind turbine can adapt to the low-frequency vibration characteristic of the semi-submersible type platform.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of offshore wind power generation, and particularly relates to an offshore wind turbine, a four-float pontoon semi-submersible floating platform thereof and a low-frequency tuned liquid column damper. BACKGROUND

[0002] In the case of energy shortage and serious air pollution, the development of renewable energy represented by wind energy is on the agenda. Deep sea wind power has a broad prospect. After the water depth is greater than 40 meters, floating wind turbines replace fixed wind turbines to become the main force of wind power. Floating platforms include tension leg platforms (TLP), semi-submersible platforms (Semi-Sub), barge platforms (Barge) and single column platforms (Spar). Among them, the semi-submersible platform has strong application prospects due to its good water depth adaptability and other advantages.

[0003] The semi-submersible wind turbine is anchored by a mooring system and a floating platform, and is fixed with a high flexible tower to carry a cabin and flexible blades of a rigid-flexible hybrid structure. Among them, the four-float pontoon semi-submersible floating platform has strong competitiveness in the wind power market in Europe and Asia due to its superior seakeeping performance. Due to the low-frequency roll and pitch response of the floating platform under wind and wave load, even a small amplitude rotation of the lower floating foundation will be transmitted to the upper structure through the tower, causing large amplitude motion at the cabin position, causing turbulence in the wind field, and causing strong wind and wave coupling vibration effect, aggravating the fatigue damage of the whole machine.

[0004] Therefore, using advanced control technology to adjust the motion of the platform is a key measure to improve the overall performance and stability of offshore wind turbines. In the prior art, the traditional tuned liquid column damper (TLCD) mainly uses a straight pipe, which has the problems of low space utilization, narrow frequency adjustment range, limited installation space, and is difficult to adapt to the low-frequency vibration characteristics of the semi-submersible platform. SUMMARY

[0005] Therefore, in order to solve the problems existing in the prior art, the purpose of the present application is to provide an offshore wind turbine, a four-float pontoon semi-submersible floating platform thereof and a low-frequency tuned liquid column damper.

[0006] To achieve the above purpose, the present application provides the following technical scheme:

[0007] A low-frequency tuned liquid column damper, comprising three horizontal tuned liquid columns arranged uniformly in a ring shape, and a vertical tuned liquid column is arranged at the radially outward end of each of the three horizontal tuned liquid columns;

[0008] The horizontal tuned liquid column comprises a horizontal serpentine pipe, and a first horizontal pipe section and a second horizontal pipe section are arranged at the two ends of the horizontal serpentine pipe, respectively;

[0009] The vertical tuning liquid column comprises a vertical serpentine pipe, and a lower end of the vertical serpentine pipe is provided with a vertical pipe section;

[0010] The horizontal tuning liquid column and the vertical tuning liquid column are connected through adjacent first horizontal pipe sections and vertical pipe sections;

[0011] Three adjacent second horizontal pipe sections between three horizontal tuning liquid columns are connected;

[0012] A damping valve is arranged in the second horizontal pipe section, and the horizontal tuning liquid column and the vertical tuning liquid column are filled with damping liquid.

[0013] Further, the damping liquid is a mixture of seawater and ethylene glycol, and the density range is 1150-1250 kg / m 3 , and the freezing point is ≤-30℃.

[0014] Further, the curvature radius to pipe diameter ratio of the bending section of the horizontal serpentine pipe and the vertical serpentine pipe is 2.5-3.0.

[0015] Further, the opening rate of the damping valve can be continuously adjusted between 0% and 80%, and the liquid column damping ratio control range is 0.03-0.15.

[0016] Further, adjacent first horizontal pipe sections and vertical pipe sections are connected through a circular arc pipe with an included angle of 90°.

[0017] The application further provides a four-float semi-submersible floating platform, comprising a center float and three peripheral floats, the three peripheral floats are arranged in a ring shape around the axis of the center float; horizontal connecting cylinders are arranged in the radial direction between the center float and the three peripheral floats, and the horizontal connecting cylinders connect the center float and the corresponding peripheral floats; and the low-frequency tuning liquid column damper is as described above.

[0018] Three vertical tuning liquid columns are arranged in the three peripheral floats, respectively.

[0019] Three horizontal tuning liquid columns are arranged in the three horizontal connecting cylinders, respectively.

[0020] Further, the first horizontal pipe section and the second horizontal pipe section are fixed to the pipe wall of the horizontal connecting cylinder through a rigid support, the rigid support is made of double-layer anti-corrosion steel plates, and the double-layer anti-corrosion steel plates are coated with a polyurethane damping layer on the surface;

[0021] The vertical pipe section is fixed to the inner wall of the cabin of the peripheral float through a multi-directional articulated flexible connecting piece, the multi-directional articulated flexible connecting piece allows the vertical pipe section to swing in multiple directions within a range of ±3°, and adapts to the dynamic deformation of the platform.

[0022] Further, the total mass of the low-frequency tuned liquid column damper accounts for 15%-20% of the ballast water mass of the four-float pontoon semi-submersible floating platform.

[0023] Further, a center base is arranged below the horizontal tuned liquid column in the center pontoon, and a lower support ring for supporting three adjacent second horizontal pipe sections is arranged on the center base, and an upper support ring above the three adjacent second horizontal pipe sections is arranged above the lower support ring, and the lower support ring and the upper support ring are fixedly connected with the center base by bolts.

[0024] The application further provides an offshore wind turbine, which comprises a tower, a nacelle and blades, and the bottom of the tower is provided with the four-float pontoon semi-submersible floating platform.

[0025] Further, the low-frequency tuned liquid column damper and the low-frequency tuned liquid column damper are both made of stainless steel and are covered with a polyurethane damping layer on the surface.

[0026] The application has the following beneficial effects:

[0027] The four-float pontoon semi-submersible floating platform of the application can optimize the damper structure, uniformly disperse the liquid column inertia force, adapt to the multi-degree-of-freedom motion of the floating platform, reduce local stress concentration, and the damper is designed with a serpentine pipe, the motion path of the liquid column is prolonged through the bending structure of the serpentine pipe, the low-frequency energy dissipation efficiency is enhanced, the frequency matching accuracy can be improved, the dynamic damper adjusting technology is integrated through the damping valve arranged in the second horizontal pipe section, the liquid column damping characteristics are optimized in real time, and the vibration control demand under complex sea conditions can be adapted. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to make the purpose, technical scheme and beneficial effects of the application clearer, the application provides the following drawings for description:

[0029] Figure 1 Fig. 1 is a structural schematic view of an embodiment of the offshore wind turbine of the application;

[0030] Figure 2 Fig. 2 is a structural schematic view of the four-float pontoon semi-submersible floating platform of the application;

[0031] Figure 3 Fig. 3 is an enlarged view of a part of the four-float pontoon semi-submersible floating platform of the application.

[0032] Legend of reference signs:

[0033] 10-Tower; 11-Nacelle; 12-Blade; 20-Four-pontoon semi-submersible floating platform; 21-Central pontoon; 22-Outer pontoons; 23-Horizontal connecting tube; 24-Central base; 25-Lower support ring; 26-Upper support ring; 30-Low-frequency tuned liquid column damper; 31-Horizontal tuned liquid column; 311-Horizontal serpentine pipe; 312-First horizontal pipe section; 313-Second horizontal pipe; 32-Vertical tuned liquid column; 321-Vertical serpentine pipe; 322-Vertical pipe section; 33-Circular arc pipe; 40-Damping valve. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0035] like Figure 1 As shown, the offshore wind turbine of this embodiment includes a tower 10, a nacelle 11, and blades 12. A four-pontoon semi-submersible floating platform 20 is provided at the bottom of the tower 10. The four-pontoon semi-submersible floating platform 20 of this embodiment includes a central pontoon 21 and three peripheral pontoons 22. The three peripheral pontoons 22 are evenly distributed in a ring relative to the axis of the central pontoon 21, that is, the angle between the axes of any two adjacent peripheral pontoons 22 is 120°, and the angle between the axes of the central pontoon 21 and the peripheral pontoons 22 is 90°. The axes of the central pontoon 21 and the peripheral pontoons 22 are located in the vertical direction. A horizontal connecting tube 23 located in the radial direction is provided between the central pontoon 21 and the three peripheral pontoons 22, and the horizontal connecting tube 23 connects the central pontoon 21 to the corresponding peripheral pontoon 22.

[0036] like Figure 2As shown, the four-pontoon semi-submersible floating platform 20 of the embodiment further comprises a low-frequency tuned liquid column damper 30. Specifically, the low-frequency tuned liquid column damper 30 of the embodiment comprises three horizontally distributed tuned liquid columns 31, and the radially outward end of each of the three horizontally distributed tuned liquid columns 31 is provided with a vertical tuned liquid column 32. That is, in the embodiment, the angle between the axes of any two adjacent horizontally distributed tuned liquid columns 31 is 120°, and the angle between the axes of the horizontally distributed tuned liquid column 31 and the vertical tuned liquid column 32 is 90°. The horizontally distributed tuned liquid column 31 comprises a horizontally distributed serpentine pipe 311, and the two ends of the horizontally distributed serpentine pipe 311 are respectively provided with a first horizontal pipe segment 312 and a second horizontal pipe segment 313. The vertical tuned liquid column 32 comprises a vertically distributed serpentine pipe 321, and the lower end of the vertically distributed serpentine pipe 321 is provided with a vertical pipe segment 322. Specifically, the horizontally distributed tuned liquid column 31 and the vertical tuned liquid column 32 are connected through the adjacent first horizontal pipe segment 312 and the vertical pipe segment 322. The three adjacent second horizontal pipe segments 313 between the three horizontally distributed tuned liquid columns 31 are connected. The second horizontal pipe segment 313 of the embodiment is provided with a damping valve 40, and the horizontally distributed tuned liquid column 31 and the vertical tuned liquid column 32 are filled with damping liquid. The damping liquid does not fill the vertical tuned liquid column 32, that is, the upper end of the vertical pipe segment 322 or the vertically distributed serpentine pipe 321 is not filled with damping liquid.

[0037] In the embodiment, the three vertical tuned liquid columns 32 are respectively arranged in the three peripheral pontoons 22. The three horizontally distributed tuned liquid columns 31 are respectively arranged in the three horizontal connecting cylinders 23.

[0038] Specifically, the low-frequency tuned liquid column damper 30 of the embodiment adopts a three-pronged star-shaped layout structure formed by the three vertical tuned liquid columns 32 and the three horizontally distributed tuned liquid columns 31. The first horizontal pipe segment 312 extends along the 120° equidistribution direction and is transitionally connected with the vertical pipe segment 322 through a 90° circular arc pipe 33. That is, the adjacent first horizontal pipe segment 312 and the vertical pipe segment 322 are transitionally connected through the circular arc pipe 33 with an included angle of 90°. The serpentine bending segment prolongs the flow path of the liquid column, significantly improves the frequency matching capability of the floating platform for low-frequency vibration characteristics, and can reduce the natural frequency of the liquid column to 0.05 Hz, matching the low-frequency vibration characteristics of the floating platform.

[0039] In the preferred embodiment of the embodiment, the damping liquid is a mixture of seawater and ethylene glycol with a ratio of 1:0.2-0.3, and the density range is 1150-1250 kg / m 3 , and the freezing point is ≤-30℃. The anti-freezing feature can realize uninterrupted operation throughout the year in harsh sea areas such as the North Sea. In the embodiment, the damping liquid 5 is a solution of seawater and ethylene glycol with a volume ratio of 1:0.25, and the density is controlled at 1180±20 kg / m 3, freezing point ≤-30℃, the liquid injection volume is 70% of the total volume of the pipeline. The opening rate of the damping valve 40 is adjusted to 50%-70%, so that the phase difference between the liquid column vibration and the platform vibration is stabilized at 180±5°, and the optimal damping effect is achieved.

[0040] In the preferred embodiment of the present embodiment, the curvature radius to diameter ratio of the curved sections of the horizontal serpentine pipeline 311 and the vertical serpentine pipeline 321 is 2.5-3.0. Under normal working conditions of wind and wave load coupling, compared with the maximum size of the straight pipeline TLCD that can be placed on the four-buoy semi-submersible floating body platform, the damping efficiency of the low-frequency tuned liquid column damper 30 can be increased by 5%-17% of the traditional TLCD; under extreme working conditions, the damping efficiency of the low-frequency tuned liquid column damper 30 will be higher, and the traditional TLCD or will face the risk of failure.

[0041] In the preferred embodiment of the present embodiment, the opening rate of the damping valve 40 can be continuously adjusted between 0% and 80%, and the liquid column damping ratio control range is 0.03-0.15. Compared with the fixed damping hole design of the traditional TLCD, the liquid column damping ratio can be dynamically adjusted (the range is 0.03-0.15), which is suitable for the vibration response characteristics of the platform under different sea conditions.

[0042] In the preferred embodiment of the present embodiment, the first horizontal pipe section 312 and the second horizontal pipe section 313 are fixed to the pipe wall of the horizontal connecting cylinder 23 through a rigid support, the rigid support is made of double-layer corrosion-resistant steel plates, the surface of the double-layer corrosion-resistant steel plates is coated with a polyurethane damping layer, and the rigid support is connected to the connecting piece embedded in the inner wall of the horizontal connecting cylinder 23 through a threaded connecting piece.

[0043] In the preferred embodiment of the present embodiment, the vertical pipe section 322 is fixed to the inner wall of the cabin of the peripheral buoy 22 through a multi-directional articulated flexible connecting piece, the multi-directional articulated flexible connecting piece is composed of a spherical hinge seat and an articulated rod, the spherical hinge seat is embedded with a polytetrafluoroethylene bushing, which allows the vertical pipe section 322 to swing in multiple directions within a range of ±3°, the articulated rod is connected to the cabin wall anchoring point through a universal joint, and a rubber gasket is arranged at the anchoring point to absorb dynamic displacement and adapt to the dynamic deformation of the platform.

[0044] In the preferred embodiment of the present embodiment, the total mass of the low-frequency tuned liquid column damper 30 accounts for 15%-20% of the ballast water mass of the four-buoy semi-submersible floating body platform 20. Through the mass replacement effect, the damping device is installed with zero additional mass, and compared with the traditional TLCD, the overall mass of the platform can be reduced by 7%-12%.

[0045] In the preferred embodiment of the present embodiment, the central buoy 21 is provided with a central base 24 below the horizontal tuning liquid column 31, the central base 24 is provided with a lower support ring 25 for supporting three adjacent second horizontal pipe sections 313, the upper side of the lower support ring 25 is provided with an upper support ring 26 above the three adjacent second horizontal pipe sections 313, and the lower support ring 25 and the upper support ring 26 are fixedly connected with the central base 24 by bolts. That is, in the present embodiment, the lower support ring 25 and the upper support ring 26 are arranged at the intersection of the three adjacent second horizontal pipe sections 313, which ensures the overall stability of the pipeline system under dynamic load.

[0046] In the present embodiment, the low-frequency tuned liquid column damper 20 and the low-frequency tuned liquid column damper 30 are made of stainless steel material, and are covered with a polyurethane damping layer on the surface. Compared with the traditional TLCD carbon steel material, the seawater corrosion resistance is improved by more than 3 times, and the service life is extended to 25 years in a marine environment with Cl- concentration ≥20000ppm.

[0047] After simulation verification by Ansys Aqwa and OpenFAST simulation software, under the coupling action of wind and wave load, compared with the maximum size straight pipe TLCD that can be placed on the four-buoy semi-submersible platform, the low-frequency tuned liquid column damper 20 can improve the damping efficiency of the traditional TLCD by 5% to 17%; under extreme conditions, the traditional TLCD or faces the risk of failure.

[0048] The present embodiment is directed to the buoy connection structure and low-frequency vibration characteristics of the four-buoy semi-submersible floating platform of the offshore wind turbine, without changing the installation and maintenance method of the upper equipment of the wind turbine, the low-frequency tuned liquid column damper 30 with the special structure described above is arranged inside the four-buoy semi-submersible floating platform 20, the traditional TLCD is designed in the form of a three-pronged star-shaped serpentine pipe, and the inertial force generated by the directional shaking of the liquid inside the pipe is used to dissipate energy, thereby producing a damping effect; the adjustable opening rate damper valve 40 arranged inside the horizontal pipe 312 and the horizontal pipe 313 is used to dynamically adjust the liquid column damping ratio; at the same time, due to the particularity of the installation position of the low-frequency tuned liquid column damper 30, it can replace the ballast water of the same quality, effectively solving the problem of significant increase in platform mass caused by installation of the traditional vibration control device, and the adverse effects caused by the change in draft depth leading to changes in the upper turbulent wind field.

[0049] The above-described embodiments are only preferred embodiments for fully illustrating the present application, and the protection scope of the present application is not limited thereto. Any equivalent replacement or transformation made by a person skilled in the art on the basis of the present application is within the protection scope of the present application. The protection scope of the present application is subject to the claims.

Claims

1. A low frequency tuned liquid column damper characterized by: Three horizontal tuning liquid columns are arranged in a ring shape, and one end of each of the three horizontal tuning liquid columns is provided with a vertical tuning liquid column; The horizontal tuning liquid column comprises a horizontal serpentine pipeline, and the two ends of the horizontal serpentine pipeline are respectively provided with a first horizontal pipe segment and a second horizontal pipe segment; The vertical tuning liquid column comprises a vertical serpentine pipeline, and the lower end of the vertical serpentine pipeline is provided with a vertical pipe segment; The horizontal tuning liquid column and the vertical tuning liquid column are connected through adjacent first horizontal pipe segments and vertical pipe segments; Three adjacent second horizontal pipe segments between the three horizontal tuning liquid columns are connected; A damping valve is arranged in the second horizontal pipe segment, and the horizontal tuning liquid column and the vertical tuning liquid column are filled with damping liquid.

2. The low-frequency tuned liquid column damper according to claim 1, characterized by: The ratio of the curvature radius to the pipe diameter of the bending segment of the horizontal serpentine pipeline and the vertical serpentine pipeline is 2.5-3.

0.

3. The low-frequency tuned liquid column damper according to claim 1, wherein: The opening rate of the damping valve can be continuously adjusted between 0% and 80%, and the damping ratio of the liquid column can be adjusted in the range of 0.03-0.

15.

4. The low-frequency tuned liquid column damper according to claim 1, wherein: Adjacent first horizontal pipe segments and vertical pipe segments are connected through a circular arc pipeline with an included angle of 90°.

5. A four pontoon semi-submersible floating platform, comprising a center pontoon and three peripheral pontoons, the three peripheral pontoons are arranged annularly and uniformly relative to the axis of the center pontoon; a horizontal connecting cylinder in the radial direction is arranged between the center pontoon and each of the three peripheral pontoons, the horizontal connecting cylinder connects the center pontoon and the corresponding peripheral pontoon; characterized in that: The low-frequency tuning liquid column damper of any one of claims 1-4 is also included; Three vertical tuning liquid columns are arranged in three peripheral pontoons, respectively; Three horizontal tuning liquid columns are arranged in three horizontal connecting cylinders, respectively.

6. The four-pontoon semi-submersible floating platform of claim 5, wherein: The first horizontal pipe segment and the second horizontal pipe segment are fixed to the pipe wall of the horizontal connecting cylinder through a rigid support, the rigid support is made of double-layer anti-corrosion steel plates, and the double-layer anti-corrosion steel plates are coated with a polyurethane damping layer on the surface; The vertical pipe segment is fixed to the inner wall of the cabin of the peripheral pontoon through a multi-directional hinged flexible connecting piece, the multi-directional hinged flexible connecting piece allows the vertical pipe segment to swing in multiple directions within a range of ±3°, and adapts to the dynamic deformation of the platform.

7. The four-pontoon semi-submersible floating platform of claim 5, wherein: The total mass of the low-frequency tuning liquid column damper accounts for 15%-20% of the ballast water mass of the four-pontoon semi-submersible floating body platform.

8. The four-pontoon semi-submersible floating platform of claim 5, wherein: A central base located below the horizontal tuning liquid column is arranged in the central pontoon, a lower support ring for supporting three adjacent second horizontal pipe segments is arranged on the central base, and an upper support ring located above the three adjacent second horizontal pipe segments is arranged above the lower support ring; the lower support ring and the upper support ring are fixedly connected to the central base through bolts.

9. An offshore wind turbine comprising a tower, a nacelle and blades, characterised in that: The bottom of the tower is provided with the four-pontoon semi-submersible floating body platform of any one of claims 5-8.

10. An offshore wind turbine according to claim 9, characterised in that: Both the low-frequency tuning liquid column damper and the low-frequency tuning liquid column damper are made of stainless steel and are coated with a polyurethane damping layer on the surface.

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