Barge type floating wind turbine platform based on vein branch structure

Abstract

The invention provides a barge type floating wind turbine platform based on a vein branch structure, which comprises a tower, a cabin fixedly arranged at the top end of the tower, wind turbine blades movably connected with the cabin and a barge type platform fixed at the bottom end of the tower, the barge type platform is a square platform, and the vein branch structure is arranged on the bottom surface of the barge type platform; the outline shape of the vein branch structure is the same as the shape of the barge type platform, the vein branch structure comprises a plurality of mutually staggered main veins and branch ribs, and the plurality of mutually staggered main veins and branch ribs form a fractal structure with a plurality of cavity gaps; the heaving stability of the barge type platform is in positive correlation with the number of fractal layers of the fractal structure; according to the barge type offshore floating platform, the excellent hydrodynamic characteristic of the giant lotus is utilized, the vein branch structure of the giant lotus is applied to the barge type offshore floating platform, the problems of large dead weight, high manufacturing cost, wave excitation sensitivity, nonlinear motion and the like of a traditional platform are solved, the system stability is improved, healthy operation of an offshore wind power system is guaranteed, and maximum utilization of wind energy is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power equipment, and in particular to a barge-type floating wind turbine platform based on a leaf vein branching structure. Background Art

[0002] Traditional energy sources are becoming increasingly depleted. Wind energy is widely used because of its abundant resources, green and clean, and renewable characteristics. At present, wind farms are mainly distributed on land and in shallow waters. However, due to factors such as land occupation, wind turbine noise, and unstable wind direction, it has become an inevitable trend to develop wind farms in deep seas with more stable and sustainable wind energy. Given that fixed-base wind turbines are only suitable for water depths of less than 50 meters, floating platforms should be used in deep seas.

[0003] At present, floating platforms are mainly divided into four categories: semi-submersible platforms, tension leg platforms, barge platforms and single-column platforms, such as Figure 3 As shown. The barge platform is connected to the seabed through a mooring system to achieve positioning purposes, and has the characteristics of a compliant platform. The barge platform has the advantages of mature technology, simple manufacturing and low maintenance costs. Its pitch and sway response is small and it can be used as an effective offshore wind turbine support structure. Figure 4 The figure shows the dynamic response of the whole system of the Barge platform equipped with the NREL-5MW wind turbine under wind and wave excitation conditions. Since the Barge platform has a shallow draft and a high overall center of gravity, it is more sensitive to wind and wave excitation and prone to deflection, making it unsuitable for deployment in harsh sea areas. At present, there are few studies on barge platforms, which are still in the early stages of conceptual design and theoretical verification. Given that the unique structure of the Barge platform is not suitable for extreme sea conditions, how to optimize the local structure of the Barge platform to improve its stability has become a hot topic in current research. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned problems and provide a barge-type wind turbine platform that can be applied to extreme sea conditions, so as to improve the stability of the offshore floating wind turbine under extreme sea conditions, thereby maintaining the continuous healthy and stable operation of the system.

[0005] To achieve the above-mentioned purpose, the present invention proposes a barge-type floating wind turbine platform based on a leaf vein branching structure, comprising a tower, a cabin fixedly arranged at the top of the tower, a wind turbine blade movably connected to the cabin, and a barge-type platform fixed at the bottom of the tower, wherein the barge-type platform is a square platform, and a leaf vein branching structure is arranged on the bottom surface of the barge-type platform, and the outer contour shape of the leaf vein branching structure is the same as that of the barge-type platform, and the leaf vein branching structure comprises a plurality of mutually staggered main veins, branches and ribs, and is connected by a plurality of mutually staggered main veins, branches and ribs. The staggered main veins, branches and ribs form a fractal structure with multiple cavities. The fractal structure is a lightweight branch structure, which is significantly lighter than traditional support structures and can maintain good stability under extreme water conditions. When affected by wind and wave loads, the Barge platform will produce obvious 6-DOF motion. There are many cavities in the fractal structure, and the energy dissipation generated by contact with the wall can effectively resist the energy impact caused by wave propulsion, thereby improving the platform motion response; the heave stability of the barge platform is positively correlated with the number of fractal layers of the fractal structure. The fractal structure is controlled by the branch level, the number of branches, the rib length, the rib direction and the number of ribs.

[0006] Furthermore, the barge-type floating wind turbine platform also includes a hub disposed at one end of the nacelle, and the nacelle is movably connected to the wind turbine blades through the hub.

[0007] Furthermore, the barge-type platform is also connected with a mooring line.

[0008] Furthermore, the number of the mooring lines is four, and one end of the four mooring lines is fixed on the four corners of the square platform of the barge-type platform at equal intervals and at the same horizontal height.

[0009] Furthermore, the leaf vein branching structure copes with extreme loads of different magnitudes in complex deep-sea environment lines by increasing the grading of main vein ribs and branch vein ribs; the grading of the leaf vein branching structure is a five-layer fractal structure, a seven-layer fractal structure and a nine-layer fractal structure.

[0010] Furthermore, the fractal structure includes a plurality of mutually staggered main veins, branches and ribs, forming main vein ribs and a plurality of branch vein ribs arranged along the length direction of the main vein ribs, and the intersection point of one end of the plurality of main vein ribs is the center point of the barge-type platform; a plurality of spacer ribs are arranged between every two branch vein ribs and between the branch vein ribs and the main vein ribs, and the spacer ribs are spaced along the length direction of the branch vein ribs and the main vein ribs, and a plurality of lattice cavities are formed between the plurality of branch vein ribs and between the branch vein ribs and the main vein ribs through the spacer ribs, and the air inside the cavities can greatly increase the buoyancy of the Barge platform.

[0011] Furthermore, the interior of the leaf vein branch structure is a hollow structure with a wall thickness of 0.06m, and ballast water can be filled inside the structure to further lower the overall center of mass of the system, thereby improving stability.

[0012] Furthermore, a parametric model of the leaf vein branch structure is constructed based on a recursive algorithm, and the leaf vein branch structure is controlled by five functions, namely, branch order, branch number, rib length, rib direction and rib number, to achieve structural optimization. Through different leaf vein structures and branch order, the load distribution of the platform on the water surface and underwater can be optimized to better support the wind turbine.

[0013] Furthermore, the tower is fixed at the center of the barge-type platform.

[0014] Furthermore, the barge-type floating wind turbine platform draws on the fact that the giant water lily can still maintain strong hydrodynamic characteristics by relying on its leaf vein branching system under severe water conditions, and applies its leaf vein branching structure to the barge-type offshore floating platform to improve the stability of the system; at the same time, based on the leaf vein branching structure of the giant water lily, a parametric model of the main vein and supporting rib structure of its bionic platform is constructed through a recursive algorithm, in order to solve the problems of traditional platforms such as heavy weight, high cost, wave excitation sensitivity, and nonlinear movement of the platform and mooring.

[0015] Compared with the prior art, the advantages of the present invention are:

[0016] 1. The present invention utilizes the excellent hydrodynamic characteristics of giant water lilies under harsh water conditions, applies its leaf vein branching structure to a barge-type offshore floating platform, and designs a floating wind turbine platform with bionic fractal characteristics. Compared with the traditional barge-type platform, the platform of the present invention adopts a lightweight branching fractal structure, which effectively reduces the platform's own weight, thereby improving the system stability and reducing the construction and maintenance costs. It effectively solves the problems of traditional platforms such as heavy weight, high cost, wave excitation sensitivity and nonlinear motion, improves the system stability, ensures the healthy operation of the offshore wind power system, and realizes the maximum utilization of wind energy.

[0017] 2. The present invention constructs a parametric model of the giant water lily branch structure through a recursive algorithm, which provides a theoretical basis for the design of a branch fractal platform, helps to analyze the influence of fractal dimension changes on the hydrodynamic performance of a barge-type offshore floating wind turbine, and controls the overall structure through five functions of branch order, branch number, rib length, rib direction and rib number, so as to achieve fine adjustment of the structure to improve its stability and bearing capacity, thereby determining the optimal fractal dimension of the wind turbine platform and obtaining the optimal stability improvement effect.

[0018] 3. Compared with the traditional barge-type platform, the present invention fully considers the characteristics of biological structures, reduces the total mass of the additional heave plate while increasing the structural strength, has excellent energy absorption characteristics, can effectively absorb and dissipate energy under extreme sea conditions such as waves and currents, further improves the long-term stability of the system, and contributes to the continuous and stable utilization of offshore wind energy, maximizing the utilization rate of wind energy.

[0019] 4. The present invention focuses on the optimized application of the number of leaf vein branches, which is suitable for different engineering environments; by selecting different leaf vein structures and branch numbers, the load distribution of the platform on the water surface and underwater is optimized to better support the wind turbine; the performance of the platform can be optimized according to external conditions such as load and water flow, providing a more flexible and efficient design for the wind turbine. This detail optimization can greatly improve the overall performance of the platform in actual use; in addition, better fluid dynamics performance can improve the stability of the platform in the water, reduce energy consumption or drag, especially when moving or maintaining position.

[0020] 5. The present invention includes but is not limited to applying the branched fractal structure to active and passive control objects of a floating platform, such as a plate-like appendage structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of a barge-type floating wind turbine platform based on a leaf vein branching structure according to an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of a fractal structure in a leaf vein branching structure of a barge-type floating wind turbine platform based on a leaf vein branching structure according to an embodiment of the present invention;

[0023] Figure 3 This is a diagram of the existing offshore floating wind turbine platform style;

[0024] Figure 4 It is a schematic diagram of the dynamic response of the barge-type platform wind turbine under wind wave excitation conditions;

[0025] Figure 5 1 is the heave response result of the barge-type platform under different fractal dimensions in the embodiment of the present invention;

[0026] Figure 6 The internal vortex distribution diagram of the bottom branch structure of the barge-type platform at different times within a cycle under wind wave excitation conditions according to an embodiment of the present invention;

[0027] Figure 7 This is a schematic diagram of the structural dimensions of a barge-type floating wind turbine platform according to an embodiment of the present invention;

[0028] Figure 8Schematic diagram of optimized relationship of leaf vein branch structure in a barge-type floating wind turbine platform according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be further described below.

[0030] This embodiment proposes a barge-type wind turbine platform that can be used in extreme sea conditions, such as Figure 1 As shown, it includes a tower 4 for supporting, a nacelle 3 fixedly arranged at the top of the tower 4, a hub 2 arranged at one end of the nacelle 3, a wind turbine blade 1 movably connected to the nacelle 3 through the hub 2, and a barge-type platform 5 fixed at the bottom of the tower 4, wherein, as Figure 7 As shown, the tower 4 is 87.6m high and is fixed to the center of the barge-type platform 5 through a 4m cylinder; the barge-type platform 5 is a square platform of 40mX40mx10m, which is connected to four mooring lines 6, and one end of the four mooring lines 6 is fixed to the four corners of the square platform of the barge-type platform 5 at equal intervals and at the same horizontal height.

[0031] like Figure 7 As shown, the bottom surface of the barge-type platform 5 is provided with a leaf vein branch structure, and the outer contour shape of the leaf vein branch structure is the same as that of the barge-type platform 5, both of which are 40mX40m square and 4m thick. The interior of the leaf vein branch structure is a hollow structure with a wall thickness of 0.06m, and ballast water can be filled inside the structure to further reduce the overall center of mass of the system, thereby improving stability; at the same time, the leaf vein branch structure includes a plurality of mutually staggered main veins, branches and ribs, forming a main vein rib, and a plurality of branch vein ribs arranged along the length direction of the main vein rib, and the intersection point of one end of the plurality of main vein ribs is the center point of the barge-type platform; a plurality of spacer ribs are arranged between every two branch vein ribs and between the branch vein ribs and the main vein ribs, and the spacer ribs are spaced along the length direction of the branch vein ribs and the main vein ribs, and a plurality of lattice cavities are formed between the plurality of branch vein ribs and between the branch vein ribs and the main vein ribs through the spacer ribs, and the air inside the cavity can greatly increase the buoyancy of the Barge platform;

[0032] The fractal structure is a lightweight branched structure, which is significantly lighter than traditional support structures and can still maintain good stability under extreme water conditions. When affected by wind and wave loads, the Barge platform will produce obvious 6-DOF movement. There are many cavities in the fractal structure, and the energy dissipation generated by contact with the wall can effectively resist the energy impact caused by wave propulsion, thereby improving the platform motion response.

[0033] Figure 6 This is the vortex distribution diagram of the fractal barge platform in the branch structure at the bottom of the platform under wind and wave excitation conditions, where the period interval is 1 / 4 of the wave period. Figure 6 (a), (b), (c), and (d) are the vortex distribution diagrams inside the fractal structure of the barge-type platform at different times in a cycle. Figure 6 It can be seen that the fractal structure of giant water lily leaf vein branches can generate more vortices. Since the fractal structure has irregular cavities, the shear force and centrifugal force on the fluid inside are enhanced, and the wall viscosity effect is intensified, making it easier to form vortices. In addition, the large vortex inside the chamber is decomposed into multiple small vortices, which increases the contact area with the wall and can effectively improve the energy dissipation effect.

[0034] In this embodiment, a parameterized model of the bionic leaf vein branch structure of the barge-type platform is constructed by a recursive algorithm, such as Figure 8 As shown in the figure, the overall structure of the leaf vein branches is controlled by five functions: branch order, branch number, rib length, rib direction and rib number. Through different leaf vein structures and branch orders, the structure is finely adjusted to improve its stability and bearing capacity, thereby optimizing the load distribution of the platform on and under the water.

[0035] In this embodiment, a bionic leaf vein branch structure parameterized model is constructed by a recursive algorithm, and the following is proposed: Figure 2 The five-layer fractal structure, the seven-layer fractal structure and the nine-layer fractal structure shown are used to consider the improvement effect of the complexity and irregularity of the fractal body on the hydrodynamic performance of the barge-type offshore floating wind turbine when the fractal dimension changes; Figure 5 These are the Barge heave response results of five-layer, seven-layer and nine-layer fractal structures: among them, the heave amplitude of the five-layer fractal structure is 2.07 meters, and the standard deviation is 0.76; the heave amplitude of the seven-layer fractal structure is 1.79 meters, and the standard deviation is 0.68; the heave amplitude of the nine-layer fractal structure is 1.83 meters, and the standard deviation is 0.67. From the above results, it can be found that with the increase of fractal dimension, the heave amplitude of the barge-type offshore floating wind turbine decreases, and the stability gradually improves. Therefore, it can be concluded that the heave stability of the Barge platform is positively correlated with the number of fractal layers, and the vein branching structure can cope with extreme loads of different magnitudes in complex deep-sea environments by increasing the number of branches.

[0036] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the content of the technical solution of the present invention and still falls within the protection scope of the present invention.

Claims

1. A barge-type floating wind turbine platform based on a leaf vein branching structure, characterized in that: The invention comprises a tower (4), a nacelle (3) fixedly arranged at the top of the tower (4), a wind turbine blade (1) movably connected to the nacelle (3), and a barge-type platform (5) fixed at the bottom of the tower (4); the barge-type platform (5) is a square platform; a leaf vein branching structure is provided on the bottom surface of the barge-type platform (5); the outer contour shape of the leaf vein branching structure is the same as that of the barge-type platform (5); the leaf vein branching structure forms a fractal structure with a plurality of cavities through a plurality of mutually interlaced main veins, branches and ribs; the fractal structure is controlled by the branching order, the number of branches, the rib length, the rib direction and the number of ribs; the heave stability of the barge-type platform (5) is positively correlated with the number of fractal layers of the fractal structure.

2. The barge-type floating wind turbine platform based on the leaf vein branching structure according to claim 1 is characterized in that: It also includes a hub (2) arranged at one end of the nacelle (3), and the nacelle (3) is movably connected to the wind turbine blade (1) through the hub (2).

3. The barge-type floating wind turbine platform based on the leaf vein branching structure according to claim 1 is characterized in that: The barge-type platform (5) is also connected to a mooring line (6).

4. The barge-type floating wind turbine platform based on the leaf vein branching structure according to claim 3 is characterized in that: The number of the mooring lines (6) is four, and one end of the four mooring lines is fixed at equal intervals and at the same horizontal height on the four corners of the square platform of the barge-type platform (5).

5. The barge-type floating wind turbine platform based on the leaf vein branching structure according to claim 1 is characterized in that: The fractal structure comprises a plurality of mutually staggered main veins, branches and ribs, forming a main vein rib and a plurality of branch vein ribs arranged along the length direction of the main vein rib, wherein the intersection point of one end of the plurality of main vein ribs is the center point of the barge-type platform (5); a plurality of spacer ribs arranged at intervals are arranged between every two branch vein ribs and between the branch vein ribs and the main vein ribs, wherein the spacer ribs are spaced along the length direction of the branch vein ribs and the main vein ribs, and a plurality of lattice-shaped cavities are formed between the plurality of branch vein ribs and between the branch vein ribs and the main vein ribs through the spacer ribs.

6. The barge-type floating wind turbine platform based on the leaf vein branching structure according to claim 5 is characterized in that: The leaf vein branching structure copes with extreme loads of different magnitudes in complex deep-sea environments by increasing the grading of main vein ribs and branch vein ribs; the grading of the leaf vein branching structure is a five-layer fractal structure, a seven-layer fractal structure, and a nine-layer fractal structure.

7. The barge-type floating wind turbine platform based on a leaf vein branching structure according to claim 1 is characterized in that: A parametric model of leaf vein branching structure is constructed based on a recursive algorithm. The leaf vein branching structure is controlled by five functions, namely, branching order, branch number, rib length, rib direction and rib number, to achieve structural optimization.

8. The barge-type floating wind turbine platform based on a leaf vein branching structure according to claim 1 is characterized in that: The interior of the leaf vein branch structure is a hollow structure with a wall thickness of 0.06m.

9. The barge-type floating wind turbine platform based on a leaf vein branching structure according to claim 1, characterized in that: The tower (4) is fixed at the center of the barge-type platform (5).

Images