A floating foundation with a nodal pontoon

Abstract

The present invention discloses a floating foundation with a nodal damping pontoon, which relates to the technical field of offshore wind power engineering. The floating foundation includes at least three pontoon components, and two adjacent pontoon components are connected by a cross brace. A nodal pontoon for providing buoyancy is provided in the middle of the cross brace. One end of an inclined brace is connected to the pontoon component, and the other end is connected to the nodal pontoon. Connecting the inclined brace to the cross brace through the nodal pontoon not only enhances the connection stability between two adjacent pontoon components, but also strengthens the structural strength at the connection node between the inclined brace and the cross brace. Moreover, by arranging a nodal pontoon for providing buoyancy on the cross brace connecting two adjacent pontoon components, the vertical wetted surface area of the floating foundation is increased, which is beneficial to reducing the heave of the floating foundation by increasing the area in the vertical direction, and prolongs the service life of the mooring chain, the wind turbine and the cable.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore wind power engineering, and particularly relates to a floating foundation with a node damping floating box. Background Art

[0002] With the rapid development of the offshore wind power industry in China, nearshore wind resources have been gradually developed, and currently the offshore wind power industry is gradually further developing towards deep waters. Compared with traditional pile foundations and jacket foundations, the floating foundation form has the advantages of strong adaptability to deep water conditions, better utilization of wind energy resources, etc., and with the increase of water depth, the advantages of the floating foundation form will become more obvious.

[0003] At present, the floating foundations of floating wind turbines are mostly of the three-column structure type. The columns are connected and the structure is strengthened through cross braces, diagonal braces, etc., which makes the space truss structure extremely complex, increases the steel consumption, and at the same time, due to numerous nodes, the fatigue problem is prominent. At the same time, due to the rapid increase in the power generation of wind turbines, the size of the floating foundation structure is getting larger and larger, the operating load is getting higher and higher, and after being affected by waves and ocean currents at the sea surface, it will undergo surge, sway, yaw, roll, pitch, and heave motions, and the motion amplitude is relatively large, which is not conducive to wind turbine power generation and will also increase the impact on the foundation fatigue. Summary of the Invention

[0004] Aiming at the defects existing in the prior art, the purpose of the present invention is to provide a floating foundation with a node damping floating box to solve the problems of weak connection nodes of the floating foundation and poor swaying and heaving performance of the floating foundation in the prior art.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is:

[0006] The present application provides a floating foundation with a node floating box, including at least three floating box components. Adjacent two of the above floating box components are connected by a cross brace, and a node floating box for providing buoyancy is arranged in the middle of the above cross brace. One end of a diagonal brace is connected to the above floating box component, and the other end is connected to the above node floating box.

[0007] In some alternative embodiments, the above node floating box is of a hollow structure and is a cylinder with a set diameter.

[0008] In some alternative embodiments, according to the set diameter of the above node floating box is determined, where F is the set wave force borne by the above node floating box, C m is the inertia force coefficient, C d is the drag force coefficient, u is the relative velocity of the water particle perpendicular to the axis of the above node floating box, is the acceleration of the water particle perpendicular to the axis of the above node floating box, D is the set diameter of the above node floating box, and ρ is the seawater density.

[0009] In some alternative embodiments, a damping assembly is provided inside the above-mentioned node buoy.

[0010] In some alternative embodiments, the above-mentioned damping assembly includes a ballast mass block, which is arranged inside the above-mentioned node buoy through a spring and a damper with a set stiffness.

[0011] In some alternative embodiments, the telescopic directions of the above-mentioned spring and the above-mentioned damper are parallel to the axis of the above-mentioned cross brace.

[0012] In some alternative embodiments, a support member for supporting the above-mentioned ballast mass block is further provided inside the above-mentioned node buoy, so as to enable the above-mentioned ballast mass block to slide along the telescopic direction of the above-mentioned damping assembly.

[0013] In some alternative embodiments, the above-mentioned node buoy is located at the midpoint of the above-mentioned cross brace, there are two of the above-mentioned diagonal braces, one end of each of the two above-mentioned diagonal braces is respectively connected to two adjacent above-mentioned buoy assemblies, and the other end is connected to the above-mentioned node buoy located between the two above-mentioned buoy assemblies.

[0014] In some alternative embodiments, the above-mentioned buoy assembly includes:

[0015] A buoy column, the above-mentioned diagonal brace is connected to the arc-shaped side wall of the above-mentioned buoy column;

[0016] A damping box, which is connected to the bottom of the above-mentioned buoy column, and the above-mentioned cross brace is connected to the above-mentioned damping box.

[0017] In some alternative embodiments, the above-mentioned damping box is cylindrical and has a diameter larger than that of the above-mentioned buoy column.

[0018] Compared with the prior art, the advantages of the present invention are as follows: connecting the diagonal brace to the cross brace through the node buoy not only enhances the connection stability between two adjacent buoy assemblies, but also strengthens the structural strength at the connection node between the diagonal brace and the cross brace; and by arranging a node buoy for providing buoyancy on the cross brace connecting two adjacent buoy assemblies, the vertical wet surface area of the floating foundation is increased, which is beneficial to reducing the heave of the floating foundation by increasing the area in the vertical direction, and prolongs the service life of the mooring chain, the wind turbine and the cable. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1Schematic diagram of the structure of a floating foundation with node pontoons according to the present invention;

[0021] Figure 2 is Figure 1 side view schematic diagram;

[0022] Figure 3 is Figure 1 top view schematic diagram;

[0023] Figure 4 is Figure 1 bottom view schematic diagram;

[0024] Figure 5 is Figure 1 perspective schematic diagram of the node pontoon in

[0025] In the figure: 1. Pontoon assembly; 11. Buoy column; 12. Damping box; 21. Cross brace; 211. Right cross brace; 212. Left cross brace; 22. Node pontoon; 23. Diagonal brace; 24. Connecting rod; 3. Ballast mass; 41. Spring; 42. Damper. Detailed implementation manners

[0026] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0027] The following further elaborates on the embodiments of the present invention with reference to the accompanying drawings.

[0028] The present application provides a floating foundation with node pontoons, including at least three pontoon assemblies 1. Two adjacent pontoon assemblies 1 are connected by a cross brace 21. A node pontoon 22 for providing buoyancy is provided in the middle of the cross brace 21. One end of a diagonal brace 23 is connected to the pontoon assembly 1, and the other end is connected to the node pontoon 22.

[0029] It can be understood that the node pontoon 22 is located at the connection node of the diagonal brace 23 and the cross brace 21, thereby increasing the node area for the connection of the diagonal brace 23 and the cross brace 21, improving the structural strength and making the connection more stable. On the other hand, the node pontoon 22 also increases the wet surface area of the floating foundation in the vertical direction, and can effectively reduce the up-and-down heaving of the floating foundation when encountering waves.

[0030] It should be noted that the cross-sectional area of the node pontoon 22 in the vertical direction should be greater than the cross-sectional area of the cross brace 21 in the vertical direction to increase the wet surface area on the cross brace 21.

[0031] In this example, the above-mentioned node floating box 22 is of a hollow structure and is a cylinder with a set diameter.

[0032] It can be understood that setting the node floating box 22 as a hollow structure can further increase the buoyancy of the node floating box 22. At the same time, compared with structures of other shapes, the cylindrical node floating box is more balanced in force in all directions, thereby further reducing the vertical heaving generated when the floating foundation encounters waves.

[0033] Further, according to the set diameter of the above-mentioned node floating box 22 is determined, where F is the set wave force borne by the node floating box 22, C m is the inertia force coefficient, C d is the drag force coefficient, u is the relative velocity of the water particle perpendicular to the axis of the above-mentioned node floating box 22, is the acceleration of the water particle perpendicular to the axis of the above-mentioned node floating box 22, D is the set diameter of the above-mentioned node floating box 22, and ρ is the density of seawater.

[0034] It can be understood that the cylindrical node floating box 22 is immersed in the water body, and its set diameter D is specifically set according to the set wave force F to be borne. By increasing the diameter of the node floating box 22, the wave force borne by the node floating box 22 can be improved. Of course, the buoyancy and the wave force borne between the node floating box 22 and the floating box assembly 1 should be reasonably distributed.

[0035] In some alternative embodiments, a damping assembly is provided inside the above-mentioned node floating box 22.

[0036] The node floating box 22 with a hollow interior provides an installation space for installing a damping assembly inside. By installing a tuned mass damper (TMD) with appropriate stiffness inside, the floating foundation can have a roll damping effect and can effectively reduce the sway and roll of the floating foundation.

[0037] Further, the above-mentioned damping assembly includes a fixed ballast mass block 3, which is arranged inside the above-mentioned node floating box 22 through a spring 41 and a damper 42 with set stiffness.

[0038] Specifically, there are two springs 41 and two dampers 42 respectively. One end of each spring 41 and each damper 42 is connected to the inner wall of the node floating box 22, and the other end is connected to the fixed ballast mass block 3, so that the fixed ballast mass block 3 is suspended inside the node floating box 22.

[0039] It can be understood that the natural frequency of the damping component can be controlled by adjusting the stiffness of the spring 41. According to experiments and theoretical analyses, for the damping component with the fixed ballast mass block 3, when its natural frequency is slightly greater than the frequency of the external wave excitation load, the effect of reducing vibration and sway of the floating wind turbine is the best. Therefore, when the main frequency of the wave excitation load in the target operation sea area is known, the natural frequency of the damping component can be set to be slightly greater than the wave excitation load frequency. Among them, the stiffness of the spring 41 can be determined according to the natural frequency formula, and the natural frequency calculation formula is: Where T is the wave period, ω is the circular frequency, m is the mass of the ballast mass block 3, and k is the stiffness of the spring 41.

[0040] For example, in the target operation sea area, the wave period under the rated wind speed of the wind turbine is usually 5 - 7 s, and the mass of the ballast mass block 3 is usually about 1% - 10% of the mass of the vibration reduction structure. Assuming the mass of the wind turbine is 5000 tons, the ballast mass block 3 can be taken as a 50 t steel block. At this time, the stiffness of the spring 41 is between 40230 N / m and 78877 N / m.

[0041] The spring 41 in this example is a cylindrical helical spring, and its specific type can be selected according to actual requirements.

[0042] Preferably, the telescopic direction of the above-mentioned spring 41 and the above-mentioned damper 42 is parallel to the axis of the above-mentioned cross brace 21.

[0043] It can be understood that the cross brace 21 includes a left cross brace 212 and a right cross brace 211. One end of the left cross brace 212 and the right cross brace 211 are respectively connected to a floating box assembly 1, and the other ends are both connected to the node floating box 22, and the left cross brace 212 and the right cross brace 211 are on the same axis. Therefore, making the telescopic direction of the spring 41 and the damper 42 parallel to the axis of the left cross brace 212 and the right cross brace 211 enables the floating foundation to better transmit the structural vibration to the spring 41 and the damper 42 when subjected to external forces, thereby further improving the anti-sway and anti-vibration effect of the floating foundation.

[0044] In some alternative embodiments, the above-mentioned node floating box 22 is also filled with damping liquid, and the above-mentioned fixed ballast mass block 3 is partially submerged or completely immersed in the above-mentioned damping liquid.

[0045] When the damping component works, the ballast mass block 3 swings left and right in the damping liquid, and the ballast mass block 3 drives part of the damping liquid to vibrate. Due to the fluid-structure coupling effect of the damping liquid, additional liquid mass is provided for the damping component. The damping liquid can not only reduce the static elongation of the spring 41, but also effectively restrain the swinging problem of the ballast mass block 3 in the vertical direction, effectively ensuring the stability of the damping component during the movement process.

[0046] It should be noted that the viscosity coefficient of the damping fluid also affects the magnitude of the damping parameter, and the damping parameter increases with the increase of the viscosity coefficient of the damping fluid. When selecting the damping fluid, a damping fluid with stable viscosity-temperature characteristics can be selected to ensure that the damping parameter of the damping component remains stable during operation.

[0047] At the same time, a damping component is arranged in the node floating box 22 and filled with damping fluid, which can help the floating foundation further reduce the structural center of gravity, is helpful for the stability of the structure on the water surface, and reduces the swing angle of the wind turbine.

[0048] In some alternative embodiments, a support member for supporting the ballast mass block 3 is further provided in the node floating box 22, so that the ballast mass block 3 can slide along the telescopic direction of the damping component.

[0049] It can be understood that the support member can prevent the ballast mass block 3 from swinging in the vertical direction and will not affect the telescopic movement of the damping component in the horizontal direction.

[0050] In some alternative embodiments, the support member is a pulley with a set height fixed below the ballast mass block 3. The pulley can support the ballast mass block 3 and can slide on the bottom wall of the node floating box 22.

[0051] In some alternative embodiments, the above-mentioned node floating box 22 is located at the midpoint of the above-mentioned cross brace 21. There are two of the above-mentioned diagonal braces 23. One end of each of the two diagonal braces 23 is respectively connected to two adjacent above-mentioned floating box assemblies 1, and the other end is connected to the above-mentioned node floating box 22 located between the two above-mentioned floating box assemblies 1.

[0052] In this example, there are three floating box assemblies 1, which are interconnected by cross braces 21 to form a triangular stable structure. The diagonal braces 23 and cross braces 21 between two adjacent floating box assemblies 1 form a K-shaped structure, and a cylindrical node floating box 22 is arranged at the K-shaped node.

[0053] Through experiments and calculation and analysis, it can be known that for a floating foundation with a cylindrical floating box with a K-shaped node, the result of its RAOs (response amplitude operator) is better than that of a floating foundation without a cylindrical floating box with a K-shaped node.

[0054] Of course, the number of the floating box assemblies 1 can be specifically set according to the required buoyancy foundation. Similarly, the numbers of the cross braces 21 and diagonal braces 23 are not specifically limited. For example, in some alternative embodiments, between two adjacent floating box assemblies 1, two cross braces 21 are arranged at intervals, and a plurality of diagonal braces 23 are arranged between the two cross braces 21 to form a K-shaped node or a Y-shaped node, and a node floating box 22 is arranged at each node.

[0055] Optionally, a connecting rod 24 is further provided between the two floating box assemblies 1 described above. The two ends of the connecting rod 24 are respectively connected to the nodes where the diagonal brace 23 is connected to the floating box assembly 1.

[0056] Setting the connecting rod 24 can further stabilize the connection between the two floating box assemblies 1.

[0057] In this example, the connecting rod 24, the diagonal brace 23, the cross brace 21, and the floating box assembly 1 can all be fixedly connected by welding.

[0058] In some alternative embodiments, the above-mentioned floating box assembly 1 includes a floating drum column 11 and a damping box 12. The above-mentioned diagonal brace 23 is connected to the arc-shaped side wall of the floating drum column 11; the damping box 12 is connected to the bottom of the floating drum column 11, and the above-mentioned first cross brace 21 is connected to the damping box 12.

[0059] Both the floating drum column 11 and the damping box 12 are of a hollow structure inside to increase buoyancy. An installation part for installing a wind power tower is provided on any one of the floating drum columns 11.

[0060] In some alternative embodiments, the shape of the damping box 12 can be frustum-shaped, cylindrical, etc.

[0061] In this example, the above-mentioned damping box 12 is cylindrical and has a diameter larger than that of the floating drum column 11.

[0062] Since the damping box 12 is immersed in the water body, setting the damping box 12 as a cylinder with a diameter larger than that of the floating drum column 11 can not only make the stability of the entire floating foundation better, but also increase the wet surface area, effectively reducing the up-and-down heaving of the floating foundation when encountering waves.

[0063] Optionally, a ballast mechanism can be arranged in the damping box 12 to increase the ballast and buoyancy.

[0064] The working principle of the embodiments of the present application is as follows: According to the buoyancy, ballast, and the set wave force that the floating foundation as a whole needs to bear, determine the number of floating box assemblies 1 and the cross-sectional area of the node floating box 22, adjust the set stiffness of the spring 41 in the node floating box 22, and after injecting the damping liquid, install the wind power tower on any one of the floating drum columns 11, and then it can be placed in the target operation sea area.

[0065] A floating foundation with node pontoons according to the present invention connects the diagonal braces to the transverse braces through the node pontoons, which not only enhances the connection stability between adjacent two pontoon components, but also strengthens the structural strength at the connection nodes between the diagonal braces and the transverse braces. And by providing node pontoons for buoyancy on the transverse braces connecting adjacent two pontoon components, the vertical wet surface area of the floating foundation is increased, which is beneficial to reducing the heaving of the floating foundation by increasing the area in the vertical direction, and prolongs the service life of the mooring anchor chain, the wind turbine and the cable. The node pontoons also provide installation space for installing a tuned mass damper (TMD) inside. By installing damping components with appropriate stiffness inside, the floating foundation can have the function of reducing roll and vibration. By the method of combining a circular damping box and a K-type node pontoon, the stability of the floating foundation can be effectively improved, the vertical wet surface area can be increased to reduce the heaving of the foundation, and the roll and vibration reduction effect of the floating foundation can be further improved.

[0066] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0067] It should be noted that in the present application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0068] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but rather will be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A floating foundation with a nodal pontoon, characterized in that, It includes at least three pontoon components (1), and two adjacent pontoon components (1) are connected by a cross brace (21). A node pontoon (22) for providing buoyancy is provided in the middle of the cross brace (21). One end of an inclined brace (23) is connected to the pontoon component (1), and the other end is connected to the node pontoon (22). A damping component is provided in the node pontoon (22). The damping component includes a ballast mass block (3), which is arranged in the node pontoon (22) through a spring (41) with a set stiffness and a damper (42). The telescopic directions of the spring (41) and the damper (42) are parallel to the axis of the cross brace (21).

2. The floating foundation with node pontoons according to claim 1, characterized in that, The node pontoon (22) is of a hollow structure and is a cylinder with a set diameter.

3. The floating foundation with a node pontoon according to claim 2, characterized in that, According to determine the set diameter of the node floating box (22), where F is the set wave force borne by the node floating box (22), is the inertia force coefficient, is the drag force coefficient, u is the relative velocity of the water particle perpendicular to the axis of the node floating box (22), is the acceleration of the water particle perpendicular to the axis of the node floating box (22), D is the set diameter of the node floating box (22), and ρ is the seawater density.

4. The floating foundation with node pontoons as described in claim 1, characterized in that, A support member for supporting the ballast mass block (3) is further provided in the node pontoon (22) to enable the ballast mass block (3) to slide along the telescopic direction of the damping component.

5. The floating foundation with node pontoons as claimed in claim 1, characterized in that, The node pontoon (22) is located at the midpoint of the cross brace (21). There are two inclined braces (23). One ends of the two inclined braces (23) are respectively connected to two adjacent pontoon components (1), and the other ends are connected to the node pontoon (22) located between the two pontoon components (1).

6. The floating foundation with node pontoons as claimed in claim 1, wherein, The pontoon component (1) includes: A pontoon column (11), and the inclined brace (23) is connected to the arc-shaped side wall of the pontoon column (11). A damping box (12), which is connected to the bottom of the pontoon column (11), and the cross brace (21) is connected to the damping box (12).

7. The floating foundation with node pontoons as claimed in claim 6, characterized in that, The damping box (12) is cylindrical and has a diameter larger than that of the pontoon column (11).

Images