CN115817741A

CN115817741A - Floating foundation with node buoyancy tanks

Info

Publication number: CN115817741A
Application number: CN202211467992.XA
Authority: CN
Inventors: 孟轲; 孔凡富; 雷慧; 王允; 麻妍妍
Original assignee: 719th Research Institute of CSIC
Current assignee: 719th Research Institute of CSIC
Priority date: 2022-11-22
Filing date: 2022-11-22
Publication date: 2023-03-21

Abstract

The invention discloses a floating foundation with node damping buoyancy tanks, and relates to the technical field of offshore wind power engineering. The diagonal brace is connected with the cross brace through the node buoyancy tanks, so that the connection stability of two adjacent buoyancy tank assemblies is enhanced, and the structural strength of the connection node of the diagonal brace and the cross brace is enhanced; and through on the stull between connecting adjacent two flotation tank subassemblies, set up the node flotation tank that is used for providing buoyancy to increased the vertical wet surface area of floating foundation, it is beneficial to reducing the heaving of floating foundation through the area of increase vertical direction, prolongs the life of mooring anchor chain, fan and cable.

Description

Floating foundation with node buoyancy tanks

Technical Field

The invention relates to the technical field of offshore wind power engineering, in particular to a floating foundation with a node damping buoyancy tank.

Background

With the rapid development of the offshore wind power industry in China, offshore wind resources are developed successively, and at present, the offshore wind power industry gradually develops towards deep sea. Compared with the traditional pile type foundation and jacket foundation and the floating type foundation, the floating type foundation has the advantages of being strong in adaptation to deep water conditions, capable of better utilizing wind energy resources and the like, and the advantages of the floating type foundation are more obvious along with the increase of water depth.

At present, the floating foundation of floating formula fan is mostly three stand column structure types, realizes the enhancement of connection and structure through stull, bracing etc. between each stand, and this makes the space truss structure unusual complicated, increases the steel volume, simultaneously because the node is numerous, fatigue problem is outstanding. Meanwhile, as the generating power of the wind turbine generator is rapidly increased, the floating foundation structure is larger and larger in size and higher in operating load, and after the action of waves and ocean currents is applied to the sea surface, the floating foundation structure can generate swaying, surging, yawing, pitching and heaving motions, the motion amplitude is large, the wind turbine generator is not beneficial to generating electricity, and the influence on the foundation fatigue is increased.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a floating foundation with a node damping buoyancy tank, so as to solve the problems that in the prior art, a connecting node of the floating foundation is weak, and the swinging and heaving performance of the floating foundation is poor.

In order to achieve the purpose, the invention adopts the technical scheme that:

the application provides a floating foundation with node flotation tank, including at least three flotation tank subassembly, two adjacent above-mentioned flotation tank subassemblies pass through the stull and connect, and above-mentioned stull middle part is equipped with the node flotation tank that is used for providing buoyancy, and the one end and the above-mentioned flotation tank subassembly of bracing are connected, and the other end is connected with above-mentioned node flotation tank.

In some optional embodiments, the node buoyancy tank is a hollow structure and is a cylinder with a set diameter.

In some alternative embodiments, according to

Determining a set diameter of said nodal pontoons, wherein F is a set wave force experienced by said nodal pontoons, C _m Is coefficient of inertia force, C _d And is the drag force coefficient, u is the relative velocity of the water particle perpendicular to the node buoyancy tank axis,

the acceleration of water particles vertical to the axis of the node buoyancy tank, D the set diameter of the node buoyancy tank and rho the seawater density.

In some optional embodiments, a damping assembly is disposed within the nodal buoyancy tank.

In some alternative embodiments, the damping assembly includes a ballast mass disposed within the nodal buoyancy tank by a spring and damper having a set stiffness.

In some alternative embodiments, the extension and contraction directions of the spring and the damper are parallel to the axis of the cross brace.

In some alternative embodiments, a support member for supporting the ballast mass is further disposed in the nodal buoyancy tank for sliding the ballast mass in the telescopic direction of the damping assembly.

In some alternative embodiments, the nodal buoyancy tanks are located at the midpoint of the cross braces, and the two diagonal braces are provided, and one end of each of the two diagonal braces is connected to two adjacent buoyancy tank assemblies, and the other end of each of the two diagonal braces is connected to the nodal buoyancy tank located between the two buoyancy tank assemblies.

In some alternative embodiments, the buoyancy tank assembly comprises:

the inclined strut is connected with the arc-shaped side wall of the floating cylinder upright post;

and the damping box is connected to the bottom of the buoy upright post, and the cross brace is connected with the damping box.

In some alternative embodiments, the damping chamber is cylindrical and has a diameter greater than the diameter of the pontoon column.

Compared with the prior art, the invention has the advantages that: the diagonal brace is connected with the cross brace through the node buoyancy tanks, so that the connection stability of two adjacent buoyancy tank assemblies is enhanced, and the structural strength of the connection node of the diagonal brace and the cross brace is enhanced; and through on the stull between two adjacent flotation tank subassemblies of connection, set up the node flotation tank that is used for providing buoyancy to increased the vertical wet surface area of floating foundation, it is beneficial to reducing the heaving of floating foundation through the area of increase vertical direction, prolongs the life of mooring anchor chain, fan and cable.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic structural view of a floating foundation with nodal pontoons according to the present invention;

FIG. 2 is a side view of FIG. 1;

FIG. 3 is a top view of FIG. 1;

FIG. 4 is a schematic bottom view of FIG. 1;

fig. 5 is a perspective schematic view of the nodal buoyancy tank of fig. 1.

In the figure: 1. a buoyancy tank assembly; 11. a pontoon column; 12. a damping box; 21. a cross brace; 211. a right cross brace; 212. a left cross brace; 22. a node buoyancy tank; 23. bracing; 24. a connecting rod; 3. a ballast mass block; 41. a spring; 42. a damper.

Detailed Description

In order to make the objects, 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 drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

The application provides a floating foundation with node flotation tank, including at least three flotation tank subassembly 1, adjacent two above-mentioned flotation tank subassemblies 1 are connected through stull 21, and above-mentioned stull 21 middle part is equipped with the node flotation tank 22 that is used for providing buoyancy, and the one end of bracing 23 is connected with above-mentioned flotation tank subassembly 1, and the other end is connected with above-mentioned node flotation tank 22.

It can be understood that the node buoyancy tanks 22 are located at the connection nodes of the inclined struts 23 and the cross struts 21, so that the node area is increased for the connection of the inclined struts 23 and the cross struts 21, the structural strength is improved, and the connection is more stable. On the other hand, the node buoyancy tank 22 also increases the wet surface area in the vertical direction of the floating foundation, and can effectively reduce the vertical heaving generated when the floating foundation meets the waves.

It should be noted that the sectional area of the node buoyancy tank 22 in the vertical direction should be larger than the sectional area of the wale 21 in the vertical direction to increase the wet surface area on the wale 21.

In this example, the nodal pontoons 22 are hollow and are cylindrical with a set diameter.

It will be appreciated that by providing the nodal pontoons 22 as hollow structures, the buoyancy of the nodal pontoons 22 can be further increased, while the cylindrical nodal pontoons are more balanced in terms of forces in all directions than in other shapes, thereby further reducing the heave of the floating foundation when it encounters waves.

Further in accordance with

Determining the set diameter of the nodal pontoons 22, wherein F is the set wave force experienced by the nodal pontoons 22, C _m Is the coefficient of inertia force, C _d Is the drag coefficient, u is waterThe relative velocity of the particles perpendicular to the axis of the node buoyancy tank 22,

d is the acceleration of the water particles perpendicular to the axis of the nodal buoyancy tank 22, D is the set diameter of the nodal buoyancy tank 22, and ρ is the seawater density.

It will be appreciated that the cylindrical nodal pontoons 22 are submerged in the body of water with a set diameter D specifically set according to the set wave force F to be experienced. By increasing the diameter of the nodal pontoons 22 to increase the wave forces experienced by the nodal pontoons 22, of course, the buoyancy and wave forces experienced between the nodal pontoons 22 and the pontoon assemblies 1 should be distributed appropriately.

In some alternative embodiments, a damping assembly is provided within the nodal pontoons 22.

The hollow node flotation tank 22 in the interior provides installation space for installing damping components additionally in the interior, and through the Tuned Mass Damper (TMD) of suitable rigidity of installation in the interior, can let the floating foundation possess the rolling damping effect and can effectively reduce the rolling and the rolling of floating foundation.

Further, the damping assembly includes a fixed ballast mass 3 disposed in the nodal buoyancy tank 22 by a spring 41 having a set stiffness and a damper 42.

Specifically, two springs 41 and two dampers 42 are respectively provided, one end of each spring 41 and one end of each damper 42 are connected to the inner wall of the node buoyancy tank 22, and the other end of each spring 41 and the other damper 42 are connected to the fixed ballast mass block 3, so that the fixed ballast mass block 3 is suspended inside the node buoyancy tank 22.

It will be appreciated that the natural frequency of the damping assembly can be controlled by adjusting the stiffness of the spring 41. According to experiments and theoretical analysis, the damping assembly with the fixed ballast mass block 3 has the best effect of damping and stabilizing the floating fan when the natural frequency of the damping assembly is slightly larger than the external wave excitation load frequency. Thus, when the dominant frequency of the target operating sea wave excitation load is known, the natural frequency of the damping assembly may be set slightly greater than the wave excitation load frequency, wherein the bounce may be determined according to the natural frequency formulaThe spring 41 stiffness, natural frequency calculation formula is:

where T is the wave period, ω is the circle frequency, m is the mass of the ballast mass block 3, and k is the stiffness of the spring 41.

For example, the sea wave period of the target operation sea area under the rated wind speed of the fan is usually 5-7 s, the mass of the ballast mass block 3 is usually 1% -10% of the mass of the damping structure, and assuming that the mass of the fan is 5000 tons, the ballast mass block 3 can be a 50t steel block, and the stiffness of the obtained spring 41 is 40230N/m to 78877N/m.

The spring 41 in this embodiment is a cylindrical coil spring, and the specific type thereof can be selected according to actual requirements.

Preferably, the extension and contraction directions of the spring 41 and the damper 42 are parallel to the axis of the wale 21.

It can be understood that the wale 21 includes a left wale 212 and a right wale 211, one end of each of the left and

right wales

212 and 211 is connected to one buoyancy tank assembly 1, the other end is connected to the node buoyancy tank 22, and the left and

right wales

212 and 211 are located on the same axis. Therefore, the extension and contraction directions of the spring 41 and the damper 42 are parallel to the axes of the left cross brace 212 and the right cross brace 211, so that the structural vibration can be better transmitted to the spring 41 and the damper 42 when the floating foundation is subjected to an external force, and the anti-rolling and shock-absorbing effects of the floating foundation are further improved.

In some alternative embodiments, the node buoyancy tanks 22 are also filled with a damping fluid, and the fixed ballast masses 3 are partially submerged or completely submerged in the damping fluid.

When the damping assembly works, the ballast mass block 3 swings left and right in the damping liquid, the ballast mass block 3 drives part of the damping liquid to vibrate, and additional liquid mass is provided for the damping assembly due to the fluid-solid coupling effect of the damping liquid. The damping liquid can reduce the static elongation of the spring 41, and can effectively restrict the swing of the ballast mass block 3 in the vertical direction, thereby effectively ensuring the stability of the damping assembly in the motion process.

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 as the viscosity coefficient of the damping fluid increases. When the damping liquid is selected, the damping liquid with stable viscosity-temperature characteristics can be selected to ensure that the damping parameters of the damping component are kept stable during working.

Meanwhile, the damping assemblies are arranged in the node buoyancy tanks 22 and filled with damping liquid, so that the gravity center of the structure of the floating foundation can be further reduced, the stability of the structure on the water surface is facilitated, and the swing angle of the fan is reduced

In some alternative embodiments, a support for supporting the ballast mass 3 is also provided within the nodal pontoons 22 so that the ballast mass 3 can slide in the telescopic direction of the damping assembly.

It will be appreciated that the support members prevent vertical oscillation of the ballast mass 3 without affecting the horizontal extension and retraction of the damping assembly.

In some alternative embodiments, the support members are pulleys fixed at a set height below the ballast mass 3, which can support the ballast mass 3, and which can slide on the bottom wall of the nodal pontoons 22.

In some alternative embodiments, the node buoyancy tank 22 is located at the midpoint of the cross brace 21, the two diagonal braces 23 are provided, one end of each of the two diagonal braces 23 is connected to two adjacent buoyancy tank assemblies 1, and the other end of each of the two diagonal braces 23 is connected to the node buoyancy tank 22 located between the two buoyancy tank assemblies 1.

In this example, the buoyancy tank assembly 1 is provided with three, interconnected by cross braces 21 to form a triangular stable structure. The inclined strut 23 and the cross strut 21 between two adjacent buoyancy tank assemblies 1 form a K-shaped structure, and cylindrical node buoyancy tanks 22 are arranged at K-shaped nodes.

Experiments and computational analysis show that the results of RAOs (response amplitude operator) of the floating foundation with the K-type node cylindrical buoyancy tanks are superior to those of the floating foundation without the K-type node cylindrical buoyancy tanks.

Of course, the number of the buoyancy tank assemblies 1 may be specifically set according to the required buoyancy foundation, and likewise, the number of the wales 21 and the inclined struts 23 is not specifically limited. For example, in some alternative embodiments, two cross braces 21 are spaced between two adjacent buoyancy tank assemblies 1, a plurality of diagonal braces 23 are disposed between the two cross braces 21 to form a K-type node or a Y-type node, and a node buoyancy tank 22 is disposed at each node.

Optionally, a connecting rod 24 is further disposed between the two buoyancy tank assemblies 1, and two ends of the connecting rod 24 are respectively connected to the joints where the inclined struts 23 are connected to the buoyancy tank assemblies 1.

The provision of the connecting rods 24 may further stabilize the connection of the two pontoon assemblies 1.

In this example, the connecting rod 24, the diagonal brace 23, the cross brace 21 and the buoyancy tank assembly 1 can be fixedly connected by welding.

In some alternative embodiments, the pontoon assembly 1 comprises a pontoon column 11 and a damping box 12, and the inclined strut 23 is connected to the arc-shaped side wall of the pontoon column 11; the damping box 12 is connected to the bottom of the pontoon column 11, and the first cross brace 21 is connected to the damping box 12.

The pontoon upright columns 11 and the damping boxes 12 are both of hollow structures inside so as to improve buoyancy, and installation parts for installing the wind power tower are arranged on any pontoon upright column 11.

In some alternative embodiments, the damper box 12 may be shaped as a truncated cone, a cylinder, or the like.

In this example, the damping box 12 is cylindrical and has a diameter greater than the diameter of the pontoon column 11.

Because the damping box 12 is immersed in the water body, the damping box 12 is set to be cylindrical with the diameter larger than that of the pontoon upright post 11, so that the stability of the whole floating foundation is better, the wet surface area is increased, and the vertical heaving generated when the floating foundation meets waves is effectively reduced.

Optionally, ballast mechanisms may be disposed in the damping tanks 12 to increase the amount of pressure loading and lift buoyancy.

The working principle of the embodiment of the application is as follows: the number of the buoyancy tank assemblies 1 and the cross-sectional area of the node buoyancy tanks 22 are determined according to buoyancy, ballast and borne set wave force required by the whole floating foundation, the set rigidity of the springs 41 in the node buoyancy tanks 22 is adjusted, and after damping liquid is injected, the wind power tower cylinder is installed on any one of the buoy columns 11 and can be placed into a target operation sea area.

According to the floating foundation with the node buoyancy tanks, the inclined struts are connected with the cross struts through the node buoyancy tanks, so that the connection stability of two adjacent buoyancy tank assemblies is enhanced, and the structural strength of the connection nodes of the inclined struts and the cross struts is enhanced; the node buoyancy tanks for providing buoyancy are arranged on the cross braces connecting the two adjacent buoyancy tank assemblies, so that the vertical wet surface area of the floating foundation is increased, the heaving of the floating foundation is reduced by increasing the area in the vertical direction, and the service lives of mooring anchor chains, fans and cables are prolonged; the node buoyancy tank also provides an installation space for installing a Tuned Mass Damper (TMD) in the node buoyancy tank, and the floating foundation can have an anti-rolling and vibration-damping effect by installing a damping component with proper rigidity in the node buoyancy tank; by the method of combining the circular damping boxes and the K-type node buoyancy tanks, the stability of the floating foundation can be effectively improved, the vertical wet surface area is increased, the foundation heaving is reduced, and the anti-rolling and shock-absorbing effects of the floating foundation are further improved.

In the description of the present application, it should be noted that the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are only for convenience in describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present application. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

It is noted that, in the present application, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.

The above description is merely exemplary of the present application and is presented to enable those skilled in the art to understand and practice the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The utility model provides a floating foundation with node flotation tank, its characterized in that includes at least three flotation tank subassembly (1), adjacent two flotation tank subassembly (1) is connected through stull (21), stull (21) middle part is equipped with node flotation tank (22) that are used for providing buoyancy, the one end of bracing (23) with flotation tank subassembly (1) is connected, the other end with node flotation tank (22) are connected.

2. Floating foundation with nodal pontoons, as claimed in claim 1, wherein said nodal pontoons (22) are hollow and cylindrical with a set diameter.

3. The floating foundation of claim 2 having nodal pontoons, according to

Determining a set diameter of the nodal buoyancy tank (22), wherein F is a set wave force experienced by the nodal buoyancy tank (22), C _m Is the coefficient of inertia force, C _d U is the relative velocity of the water particle perpendicular to the axis of the node buoyancy tank (22),

the acceleration of water particles vertical to the axis of the node buoyancy tank (22) is shown, D is the set diameter of the node buoyancy tank (22), and rho is the seawater density.

4. A floating foundation having nodal pontoons as claimed in claim 2 wherein damping assemblies are provided within said nodal pontoons (22).

5. A floating foundation having nodal pontoons as claimed in claim 4 wherein said damping assemblies comprise ballast masses (3) disposed within said nodal pontoons (22) by springs (41) and dampers (42) of set stiffness.

6. A floating foundation having nodal pontoons as claimed in claim 4 wherein the direction of extension and retraction of said springs (41) and dampers (42) is parallel to the axis of said wales (21).

7. A floating foundation having nodal pontoons as claimed in claim 5 wherein there are further provided support members within said nodal pontoons (22) for supporting said ballast masses (3) for sliding said ballast masses (3) in a telescoping direction of said damping assembly.

8. A floating foundation having nodal pontoons as claimed in claim 1 wherein said nodal pontoons (22) are located at the midpoint of said wales (21) and said braces (23) are provided in two, two of said braces (23) having one end connected to each of two adjacent pontoon assemblies (1) and the other end connected to said nodal pontoons (22) located between said two pontoon assemblies (1).

9. Floating foundation with nodal pontoons according to claim 1, wherein said pontoon assemblies (1) comprise:

the inclined strut (23) is connected with the arc-shaped side wall of the buoy upright post (11);

a damping box (12) connected to the bottom of the pontoon column (11), the wale (21) being connected with the damping box (12).

10. Floating foundation with nodal pontoons, as claimed in claim 9, wherein said damping tanks (12) are cylindrical and have a diameter greater than the diameter of said pontoon columns (11).