A new type of semi-submersible floating wind turbine foundation and a mooring parameter prediction method thereof

Abstract

This application relates to the technical field of offshore wind power generation and floating marine engineering structures, and discloses a novel semi-submersible floating wind turbine foundation and its mooring parameter prediction method, including: calculating the buoyancy ratio between the central buoy and the side buoys, the lever arm coefficient of the side buoys, the structural coupling stability coefficient of each mooring cable, the guide hole displacement amplification coefficient, and the initial length of each mooring cable; calculating the catenary restoring stiffness, guide hole tension, platform offset, and mooring radius of each mooring cable under unbalanced conditions; if the preset requirements are not met, calculating the stiffness gap of the catenary of each mooring cable, and then calculating the total mass, quantity, total volume, and position of the counterweight; recalculating the evaluation parameters based on the individual mass and position of the counterweight; until the changes in the evaluation parameters are all less than the change threshold, and outputting the final mooring parameters. This can improve the stability of the foundation and the efficiency of mooring design.

Description

Technical Field

[0001] This application relates to the fields of offshore wind power generation and floating marine engineering structure technology, such as a novel semi-submersible floating wind turbine foundation and its mooring parameter prediction method. Background Technology

[0002] As offshore wind power gradually expands into deeper and more remote areas, fixed foundations face challenges such as high construction difficulty, high construction costs, and poor seabed adaptability in deep waters. Floating wind turbine foundations, on the other hand, have become an important direction for the development of offshore wind power due to their better deep-water applicability.

[0003] Existing semi-submersible floating wind turbine foundations typically employ a support system consisting of a central column and multiple side columns, with buoyancy provided by pontoons. However, under the complex coupling effects of wind, waves, and currents, problems such as significant roll, pitch, and horizontal deviation, prominent fatigue risks at structural connections, and the impact of platform motion response on wind turbine power generation efficiency are prone to occur.

[0004] On the other hand, floating wind turbine foundations typically require mooring systems to restrict their horizontal displacement. Traditional catenary mooring systems often require long mooring cables and large anchoring radii, which are unsuitable for array deployment in areas with limited site space or complex seabed topography. Hybrid mooring methods using counterweights can improve mooring cable pretension and platform restoring force; however, there is a coupling relationship between the mass, volume, quantity, and placement of the counterweights and the length of the mooring cables. If only general calculations are performed based on water depth, environmental loads, and allowable offsets, without considering the specific configuration of the floating foundation itself, the prediction results will be difficult to reflect the impact of different platform structures on cable hole displacement, restoring stiffness requirements, and mooring force transmission efficiency.

[0005] Especially for semi-submersible foundations where the center column is fixedly connected to the central buoy, forming a double-buoy stability system with the central buoy and circumferential side buoys, and the lower side column is inclinedly connected to the upper side column and side buoys, the mooring force, after entering the platform through the cable guide hole, will form a specific force transmission path through the inclined lower side column and side buoys. The buoyancy ratio and lever arm of the central buoy and side buoys will also change the platform's response to roll, pitch, and horizontal drift. Therefore, mooring parameter prediction methods need to be combined with the above structural characteristics.

[0006] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0007] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.

[0008] This disclosure provides a novel semi-submersible floating wind turbine foundation and a method for predicting its mooring parameters, in order to improve the stability of the foundation and the efficiency of mooring design.

[0009] In some embodiments, the mooring parameter prediction method for a novel semi-submersible floating wind turbine foundation includes: a central buoy, side buoys disposed around the central buoy, side post assemblies disposed around the side buoys, and a mooring system connected to the side post assemblies; wherein the side post assembly includes: an inclined side post and a vertical side post, the bottom end of the inclined side post is connected to the side buoy, and the bottom end of the vertical side post is connected to the top end of the inclined side post; the mooring system includes: a guide cable. The system includes: holes, anchor points, mooring cables, and multiple counterweights; the prediction method includes: S10, calculating the buoyancy ratio between the central buoy and the side buoys and the side buoy lever arm coefficient based on the buoyancy of the central buoy, the buoyancy of the side buoys, and the lever arm of the side buoys; S20, calculating the force transmission index of the inclined side post based on the parameters of the inclined side post and the parameters of the guide cable hole, and then calculating the structural coupling stability coefficient and guide cable hole displacement amplification coefficient of each mooring cable; S30, calculating the force transmission index of the inclined side post based on the distance parameters between the guide cable hole and the anchor point, and the buoyancy of the side buoys; S40: Calculate the initial length of each mooring cable using the structural coupling stability coefficient and the guide hole displacement amplification coefficient; S51: Calculate the catenary recovery stiffness, guide hole tension, platform offset, and anchoring radius of each mooring cable under unbalanced conditions; Determine whether the catenary recovery stiffness, guide hole tension, platform offset, and anchoring radius all meet preset requirements; If yes, output the unbalanced scheme; if no, proceed to S50; S50: Calculate the catenary stiffness gap of each mooring cable based on the guide hole displacement amplification coefficient. S60, calculate the total mass of the counterweight based on the stiffness gap, the buoyancy ratio, the lever arm coefficient of the side float, and the force transmission index of the inclined side column; S70, calculate the number, total volume, and position of the counterweight based on the total mass of the counterweight; S80, recalculate the evaluation parameters based on the individual mass and position of the counterweight; the evaluation parameters include: mooring cable length, catenary restoring stiffness, guide hole tension, platform offset, and anchoring radius; until the change in the evaluation parameters is less than the change threshold, output the final mooring parameters.

[0010] In some embodiments, the novel semi-submersible floating wind turbine foundation includes: a central pontoon, which is a hollow cylindrical floating structure with a polygonal horizontal cross-section; a central column, whose bottom is connected to the top of the central pontoon; a side pontoon assembly, which is hollow and connected to the circumference of the central pontoon; a side column assembly, which is arranged along the circumference of the side pontoon assembly, and whose bottom is connected to the side of the side pontoon assembly; a support assembly, which is connected between the top of the side column assembly and the outer wall of the central pontoon; and a mooring system, which is connected to the side column assembly.

[0011] The present disclosure provides a novel semi-submersible floating wind turbine foundation and its mooring parameter prediction method, which can achieve the following technical effects: 1. By establishing the structural coupling relationship between the buoyancy ratio of the central buoy and the side buoys, the lever arm coefficient of the side buoys, the force transmission index of the inclined side columns, and the displacement amplification coefficient of the cable guide hole, and by incorporating the above structural parameters into the mooring parameter prediction process, the mooring parameters can reflect the influence of the floating foundation configuration on the restoring stiffness, the force on the cable guide hole, and the platform motion response. This improves the matching degree between the mooring parameter prediction results and the characteristics of the foundation structure, thereby helping to improve the overall stability of the floating foundation. 2. By first calculating the catenary recovery stiffness, guide hole tension, platform offset, and anchoring radius under the unbalanced state, and further determining the total mass, quantity, and placement of the counterweights based on the stiffness gap, the coordinated design of mooring cable length, counterweight parameters, and recovery capacity is achieved. This avoids relying solely on experience to repeatedly adjust the counterweight scheme, thus improving the design efficiency of the mooring system. 3. By establishing an iterative convergence mechanism based on the changes in evaluation parameters, the mooring cable length, catenary recovery stiffness, guide hole tension, anchor radius, and platform offset are cyclically corrected, so that the mooring parameters gradually converge to the results that meet the design requirements. This reduces the number of repeated trial calculations, lowers the computational load of parameter optimization, and improves the prediction efficiency of mooring parameters. 4. By performing unified coupled calculations of floating foundation structural parameters, environmental load parameters, and counterweight layout parameters, the joint prediction of multiple parameters such as mooring cable length, counterweight mass, counterweight position, and platform motion response is achieved. This improves the rationality and adaptability of mooring parameter configuration and provides reliable initial design parameters for the construction design, numerical simulation, and model testing of floating wind turbine foundations.

[0012] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0013] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein: Figure 1 A three-dimensional structural schematic diagram of a novel semi-submersible floating wind turbine foundation provided for embodiments of this disclosure; Figure 2 A side view of a novel semi-submersible floating wind turbine foundation provided for an embodiment of this disclosure; Figure 3 A top view of a novel semi-submersible floating wind turbine foundation provided in an embodiment of this disclosure; Figure 4 A top view of the side column assembly and support assembly in a novel semi-submersible floating wind turbine foundation provided in this embodiment of the present disclosure; Figure 5 A top view of the side column assembly and the float assembly in a novel semi-submersible floating wind turbine foundation provided in this embodiment of the present disclosure; Figure 6 This is a schematic diagram of the structure of a mooring system provided in an embodiment of the present disclosure; Figure 7 This is a schematic diagram of a novel method for predicting mooring parameters of a semi-submersible floating wind turbine foundation provided in an embodiment of this disclosure.

[0014] Figure label: 10. Central buoy; 20. Center post; 30. Side buoy assembly; 31. Side buoy; 40. Side post assembly; 41. Side post unit; 411. Inclined side post; 412. Vertical side post; 50. Support assembly; 51. Support rod; 60. Mooring system; 61. Guide hole; 62. Anchor point; 63. Mooring cable; 64. Counterweight. Detailed Implementation

[0015] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0016] The terms "first," "second," etc., used in the specification and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0017] Unless otherwise stated, the term "multiple" means two or more.

[0018] In this embodiment of the disclosure, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0019] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0020] The term "correspondence" can refer to an association or binding relationship. The correspondence between A and B means that there is an association or binding relationship between A and B.

[0021] Combination Figure 1 As shown, this disclosure provides a novel semi-submersible floating wind turbine foundation, including: a central buoy 10, a central column 20, a side buoy assembly 30, a side column assembly 40, a support assembly 50, and a mooring system 60.

[0022] The central pontoon 10 is a closed, hollow, cylindrical floating structure with a polygonal horizontal cross-section. Serving as the center of the semi-submersible floating wind turbine foundation, the central pontoon 10 provides the main buoyancy and ballast space. Optionally, the polygon has an even number of sides. Specifically, the polygon is octagonal to reduce stress concentration at connection points and facilitate connection with the central column 20 and surrounding components.

[0023] The bottom of the center column 20 is fixedly connected to the top of the central pontoon 10, and the top of the center column 20 is used to install the wind turbine tower and the wind turbine unit. Optionally, the center column 20 and the central pontoon 10 are coaxially arranged.

[0024] Side buoy assembly 30 is disposed circumferentially with central buoy 10. Optionally, side buoy assembly 30 includes a plurality of side buoys 31, the number of side buoys 31 being less than the number of sides of the polygon. Each side buoy 31 is horizontally disposed, and its first end is evenly and spaced along the circumferential direction of central buoy 10 to the circumferential wall of central buoy 10. Each side buoy 31 is a hollow structure, preferably with a rectangular cross-section, to improve bending stiffness and torsional stiffness with the same amount of steel used.

[0025] The side post assembly 40 is arranged circumferentially along the side buoy assembly 30, and the bottom of the side post assembly 40 is connected to the side of the side buoy assembly 30. Optionally, the side post assembly 40 includes a plurality of side post units 41 arranged vertically, and each side post unit 41 corresponds one-to-one with each side buoy 31. The bottom end of the side post unit 41 is connected to the second end of the corresponding buoy unit.

[0026] Optionally, each side post unit 41 includes an inclined side post 411 and a vertical side post 412. The inclined side post 411 is inclined. The horizontal distance between the bottom end of the inclined side post 411 and the central post 20 is less than the horizontal distance between the top end of the inclined side post 411 and the central post 20, that is, the bottom end of the inclined side post 411 is closer to the central post 20. Optionally, the angle between the inclined side post 411 and the vertical direction (the inclination angle of the inclined side post 411) is 20° to 30°, preferably 25°. The bottom end of the inclined side post 411 is connected to the second end of the corresponding side float 31. The vertical side post 412 is vertically arranged, and the bottom end of the vertical side post 412 is connected to the top end of the corresponding inclined side post 411.

[0027] Optionally, there are four float units and four side column units 41. In this way, the four vertical side columns 412 are arranged around the central column 20 at 90° intervals to form a square support system. This arrangement can make the platform load under the action of wind, waves and currents more evenly distributed in the circumferential direction to each side column unit 41 and float unit.

[0028] The central pontoon 10 and the side pontoon assemblies 30 form a dual pontoon system. The central pontoon 10 mainly bears the load transfer of the center column 20 and the wind turbine, while the side pontoon assemblies 30 generate anti-overturning moment through the horizontal lever arm. The dual pontoon system works together with each inclined side column 411 to improve the platform's roll, pitch, and horizontal offset control capabilities.

[0029] The support assembly 50 is connected between the top of the side column assembly 40 and the outer wall of the central float 10. It is used to improve the overall connection stiffness between the central column 20 and the vertical side columns 412, and to reduce local stress concentration during the transfer of wind turbine load to the float. Optionally, the support assembly 50 includes multiple horizontally arranged support rods 51, each corresponding to a side column unit 41. The first end of the support rod 51 is connected to the side of the corresponding vertical side column 412 facing the central column 20, and the second end of the support rod 51 is connected to the outer wall of the central column 20.

[0030] The central float, central column 20, side float assembly 30, side column assembly 40 and other components constitute the main body of the floating foundation.

[0031] Combination Figure 6As shown, the mooring system 60 is connected to the sidepost assembly 40. Optionally, the mooring system 60 includes: a guide hole 61, an anchor point 62, a mooring cable 63, and multiple counterweights 64. The guide hole 61 is connected to the outer wall of the inclined sidepost 411, the vertical sidepost 412, or the outer wall of the connection area between the outer wall of the inclined sidepost 411 and the vertical sidepost 412, and is used to guide the mooring cable 63 to connect with the floating foundation body. The anchor point 62 is located on the seabed and is used to fix the end of the mooring cable 63 away from the floating foundation body.

[0032] The cable guide hole 61 is preferably located adjacent to the corresponding inclined side post 411, so that the mooring horizontal force at the cable guide hole 61 can be transmitted to the side float 31 via the corresponding inclined side post 411. Since the inclined side post 411 is inclined relative to the vertical direction, the force transmission efficiency at the cable guide hole 61 is related to the inclination angle of the inclined side post 411, the height of the cable guide hole 61, and the lever arm of the side float. These parameters are used as structural coupling inputs in the prediction method.

[0033] Multiple counterweights 64 are spaced apart along the length of the mooring cable 63, and preferably located on the suspension section of the mooring cable 63 near the guide hole 61. Compared with setting a large mass counterweight 64 at a single point, the spaced distribution of multiple counterweights 64 can reduce local concentrated loads, reduce the risk of local wear and fatigue of the mooring cable 63, and facilitate installation, maintenance and replacement.

[0034] Preferably, the arrangement range of the multiple counterweights 64 is within 5% to 30% of the total length of the mooring cable 63 measured from the guide cable hole 61. This range is close to the platform side, which can effectively improve the pretension and restoring force contribution of the mooring cable 63 near the guide cable hole 61, while avoiding the counterweights 64 from being too close to the anchor point 62 and reducing the restoring force adjustment efficiency.

[0035] Optionally, the counterweight 64 can be a steel counterweight 64, a cast iron counterweight 64, a concrete counterweight 64, or a composite counterweight 64 with an outer corrosion-resistant protective layer. The counterweight 64 can be connected to the mooring cable 63 via clamps, sleeves, chains, or detachable connectors to meet the needs of different marine corrosive environments, installation methods, and maintenance.

[0036] In summary, the novel semi-submersible floating wind turbine foundation provided in this disclosure can achieve the following technical effects: 1. By fixing the central pontoon to the central column, the wind turbine load is first transferred to the central pontoon, and then shared by the support components, vertical side columns, inclined side columns and side pontoons, which helps to form a stable load transfer path; 2. By constructing a dual-buoy system with a central buoy and circumferential side buoys, the stability of the platform can be improved without significantly increasing the displacement; 3. By tilting the side pillars, the mooring force transmission is coordinated with the lever arm of the side buoys, reducing the risk of fatigue in the connection area.

[0037] Based on the aforementioned novel semi-submersible floating wind turbine foundation, combined with Figure 7 As shown in the figure, this disclosure provides a novel method for predicting mooring parameters of a semi-submersible floating wind turbine foundation, including: S10, based on the buoyancy of the central buoy, the buoyancy of the side buoys, and the lever arm of the side buoys, calculate the buoyancy ratio between the central buoy and the side buoys, and the lever arm coefficient of the side buoys. This specifically includes the following steps: S11, First, input the basic structure parameters, including: the geometry of the central pontoon, its displacement volume, and buoyancy. The geometric dimensions and buoyancy of each side pontoon and the horizontal lever arm relative to the central buoy Inclination angle of the inclined column And the projected length, the spatial coordinates of the cable guide hole Moment of inertia of the platform waterline High initial stability Draft and ballast condition. Indicates the first The buoyancy provided by each side buoy Number the side buoys.

[0038] Secondly, input the site location and mooring parameters. Site parameters include the design sea area water depth. Combined environmental loads of wind, waves and current and its direction, seawater density Anchorage radius constraints; mooring parameters include the depth of the guide hole into the water. Horizontal distance from cable guide hole to anchor point and vertical distance Platform allows horizontal offset Mooring cable mass per unit length Elastic axial stiffness Allowable tension Density of counterweight material Maximum permissible mass of a single counterweight .

[0039] S12, Calculate the buoyancy ratio : .

[0040] S13, Calculate the lever arm coefficient of the side buoy. : ; in, This indicates the buoyancy of the side pontoons; This indicates the horizontal lever arm of the side buoy relative to the central buoy; This indicates the pre-set reference lever arm, which can be the design horizontal lever arm of the side floats of a standard floating wind turbine foundation relative to the central float, or the average value of the horizontal lever arms of multiple side floats. This indicates the buoyancy of the central pontoon.

[0041] A larger value indicates a higher contribution of circumferential buoyancy provided by the side pontoons. The larger the value, the greater the contribution of the side pontoons to resisting the overturning moment.

[0042] Thus, the buoyancy ratio and the lever arm coefficient of the side float are calculated through S10, and the buoyancy ratio... The side float lever coefficient is used to reflect the ability of the dual float system to suppress the platform's roll and pitch. It is used to reflect the ability of the dual-buoy system to suppress the horizontal drift of the platform.

[0043] S20, based on the parameters of the inclined side post and the guide hole, calculate the force transmission index of the inclined side post, and then calculate the structural coupling stability coefficient and guide hole displacement amplification coefficient for each mooring cable. Specifically, this includes the following steps: S21, Calculate the force transmission index of the inclined side column. : ; in, Indicates the angle of inclination of the inclined column; This indicates the projected distance in the horizontal plane between the cable guide hole and the center of the corresponding side buoy; This indicates the projected length of the top and bottom ends of the inclined column in the horizontal plane. , and Both represent dimensionless correction coefficients. Specifically, This represents the foundation force transmission correction factor; This represents the tilt angle correction factor for the inclined head post, used to characterize the influence of the tilt angle of the lower head post on the direction of the mooring force and the direction of the restoring force at the cable guide hole; This represents the guide hole position correction factor, used to characterize the influence of the guide hole's spatial position on the mooring force transmission path.

[0044] S22, Calculate the structural coupling stability coefficient : ; in, Indicates the moment of inertia of the platform's waterline surface; Indicates the moment of inertia of the reference waterline surface; Indicates the initial stability level; Indicates the reference initial stability height; The center height of the central pontoon; For the firstj The height of each cable guide hole; Indicates the reference water depth; , , , , and These all represent dimensionless weighting coefficients, used to characterize the contribution of different structural parameters to the coupled stability of the structure. Specifically, This represents the weighting coefficient of the moment of inertia at the waterline. This represents the initial stability height weighting coefficient. This represents the buoyancy ratio weighting coefficient. This indicates the weighting coefficient of the buoy lever arm. This represents the force transmission weighting coefficient of the inclined side column. This represents the weighting coefficient for the height difference of the cable guide hole.

[0045] S23, Determine the displacement amplification factor of the cable guide hole. When the vertical position of the cable guide hole is within the lower 1 / 3 height range of the inclined side post from the bottom, and the horizontal lever arm of the corresponding side float relative to the central float... Greater than or equal to the reference lever arm hour, When the vertical height of the cable guide hole Greater than or equal to the center height of the central pontoon Or the horizontal projection distance between the cable guide hole and the axis of the center column is greater than or equal to the horizontal lever arm of the side float relative to the central float. When it is 1.05 times, .

[0046] In this way, by calculating the force transmission index of the inclined side column, the structural coupling stability coefficient, and the displacement amplification coefficient of the cable guide hole through S20, the structural configuration characteristics of the floating foundation are introduced into the mooring parameter prediction process. This allows the force characteristics at the cable guide hole to reflect the differences in platform structural stiffness and force transmission path, improving the accuracy of mooring force transmission analysis and providing reliable structural coupling parameters for subsequent calculations of mooring cable length and counterweight parameters.

[0047] S30, based on the distance parameter between the guide hole and the anchor point, the structural coupling stability coefficient, and the guide hole displacement amplification factor, calculate the initial length of each mooring cable. Specifically, this includes the following steps: S31, based on the direction of the environmental load and the circumferential azimuth angles of the four side pontoons, the resultant environmental force The load is distributed to each mooring cable, and the equivalent horizontal load borne by each mooring cable is obtained. For mooring cables on the windward or wave-facing side, Larger; for mooring cables on the leeward or wave-side side, Smaller or only used to maintain pretension.

[0048] S32, Calculate the initial length : ; in, This represents the relaxation coefficient of the cable length after structural correction; This indicates the horizontal distance from the cable guide hole to the anchor point; Indicates the vertical distance from the cable guide hole to the anchor point; satisfy: ; in, Represents the basic relaxation coefficient; Indicates the reference environmental load; Indicates the first j The equivalent horizontal load borne by the root mooring cable; Represents the structural coupling stability coefficient; Indicates the displacement amplification factor of the cable guide hole; , and All of these represent dimensionless correction coefficients. Specifically... This is the environmental load correction factor, used to characterize the increased redundancy requirement for mooring cable length when environmental load increases; The structural stability reduction factor is used to characterize the reduction effect of improved structural stability on the redundancy requirement of mooring cable length. This is a correction factor for the water depth of the cable guide hole, used to characterize the influence of the vertical position of the cable guide hole on the morphology of the catenary and the initial cable length.

[0049] In this way, the initial length of the mooring cable is determined by the geometric relationship between the S30 integrated cable guide hole and the anchor point, the structural coupling stability coefficient, and the displacement amplification coefficient of the cable guide hole. This allows the initial mooring scheme to take into account both the platform's structural characteristics and environmental load requirements, improves the matching degree between the initial parameters of the mooring cable and the platform's stress state, and reduces the number of subsequent parameter adjustments.

[0050] S40: Calculate the catenary restoring stiffness, guide hole tension, platform offset, and anchoring radius for each mooring cable under unbalanced conditions; determine whether the catenary restoring stiffness, guide hole tension, platform offset, and anchoring radius all meet the preset requirements; if yes, output the unbalanced solution; if not, execute S50. Specifically, this includes the following steps: S41, Under the condition of no counterweight, establish a catenary model or equivalent segmented line model for each mooring cable, and calculate the catenary restoring stiffness. Cable tension Platform offset And anchorage radius. Here, "platform" refers to the new type of semi-submersible floating wind turbine platform.

[0051] S42, Determine , Platform offset Whether the anchorage radius and the anchorage radius both meet the preset requirements. The preset requirements are: Greater than or equal to the target recovery stiffness ,and Less than or equal to the allowable tension, and the platform deflects. Both the anchoring radius and the target recovery stiffness satisfy the design constraints. ; in, Indicates the first j The equivalent horizontal load borne by the root mooring cable; Indicates the platform's allowed horizontal offset; This represents the displacement amplification factor of the cable guide hole.

[0052] S43: If yes, output the solution without counterweight. If no, execute S50.

[0053] In this way, by calculating the catenary recovery stiffness, cable hole tension, platform offset, and mooring radius without counterweight using S40, and determining whether the design requirements are met, mooring schemes that meet the design constraints can be prioritized without adding counterweights, avoiding unnecessary counterweight design and improving the efficiency of mooring scheme design.

[0054] S50, calculate the stiffness gap of the catenary for each mooring cable based on the guide hole displacement amplification factor. Specifically, this includes the following steps: S51, Calculate the target recovery stiffness : ; in, Indicates the first j The equivalent horizontal load borne by the root mooring cable; Indicates the platform's allowed horizontal offset; This represents the displacement amplification factor of the cable guide hole.

[0055] because This reflects the amplification of the displacement at the cable guide hole relative to the overall platform offset. As the size increases, the equivalent displacement control requirements at the cable guide hole become more stringent, and the target recovery stiffness increases accordingly.

[0056] S52, Calculate the stiffness notch based on the target recovery stiffness and the catenary recovery stiffness. : ; in, This indicates the catenary recovery stiffness of the mooring cable under unbalanced conditions.

[0057] In this way, by calculating the stiffness gap based on the difference between the target recovery stiffness and the catenary recovery stiffness using S50, a quantitative evaluation of the degree of inadequacy of the mooring system's recovery capability can be achieved, providing a basis for subsequent counterweight mass calculation and improving the pertinence and rationality of the counterweight design.

[0058] S60, calculate the total mass of the counterweight based on the stiffness gap, buoyancy ratio, side float lever arm coefficient, and inclined side column force transmission index. Specifically, this includes the following steps: ; in, This indicates the total mass of the counterweight; Indicates when Take when greater than 0 Otherwise, take 0; A notch indicating stiffness; Indicates the platform's allowed horizontal offset; Represents gravitational acceleration; Indicates the density of seawater; This indicates the density of the counterweight material; This indicates the efficiency of the counterweight restoring force transmission.

[0059] Among them, the counterweight restoring force transmission efficiency It is not a fixed empirical value, but is determined by the buoyancy ratio, the lever arm coefficient of the side floats, the force transmission index of the inclined side pillars, and the displacement amplification factor of the cable guide hole: ; in, Indicates the buoyancy ratio; Indicates the lever arm coefficient of the side buoy; Indicates the force transmission index of the inclined side column; Indicates the displacement amplification factor of the cable guide hole; , , , and Both represent dimensionless calibration coefficients. Specifically, This represents the basic efficiency term for the transmission of restoring force of the counterweight. This represents the buoyancy ratio efficiency coefficient of the twin pontoons. This represents the efficiency coefficient of the buoy lever arm. This represents the force transmission efficiency coefficient of the inclined column. This represents the penalty coefficient for the displacement of the cable guide hole.

[0060] In this way, by calculating the total mass of the counterweight block using S60 based on stiffness gap, buoyancy ratio, side float lever arm coefficient and inclined side column force transmission index, the mass of the counterweight block can be matched with the platform structural characteristics and mooring recovery capacity requirements, improving the rationality of the counterweight design results and helping to improve the overall stability of the floating foundation.

[0061] Optionally, the weighting coefficients in S22, the correction coefficients in S32, and the calibration coefficients in S60 are determined in the following ways: (1) Establish a parameterized model of the floating foundation-mooring system; (2) Change the buoyancy of the central buoy, the buoyancy of the side buoy, the inclination angle of the inclined side column, the position of the guide cable hole, the length of the mooring cable, and the placement of the counterweight; (3) Obtain the platform's horizontal offset, roll angle, pitch angle, recovery stiffness, and maximum mooring cable tension under different working conditions; (4) Use the least squares method, response surface methodology or multi-objective optimization method to fit the error between the prediction results and the simulation results; (5) The above coefficients are determined by taking the minimum of platform horizontal offset error, recovery stiffness error and maximum mooring cable tension error as the objective function.

[0062] The above coefficients are not independent empirical parameters, but are determined in conjunction with the central pontoon-side pontoon twin pontoon structure, the tilt angle of the inclined side pillars, and the spatial position of the cable guide holes; when the structural parameters change, the above coefficients are recalibrated accordingly.

[0063] For this embodiment, the values ​​of the weighting coefficient, correction coefficient, and calibration coefficient can be taken from the values ​​shown in Table 1.

[0064] Table 1. Values ​​of weighting coefficient, correction coefficient, and calibration coefficient

[0065] S70, calculate the number, total volume, and location of the counterweights based on their total mass. This includes the following steps: S71, Calculate the number of counterweights. : ; in, This indicates the total mass of the counterweight; This indicates the maximum permissible mass of a single counterweight.

[0066] S72, Calculate the total volume of the counterweight. : ; in, This indicates the density of the counterweight material.

[0067] The total volume of the counterweight is used to determine the counterweight geometry, effective underwater weight, and feasibility of its placement along the mooring cable suspension section, and to correct for the influence of seawater buoyancy on the counterweight's restoring force contribution.

[0068] S73, multiple counterweights are arranged within a preset proportional cable length range near the cable guide hole, and the calculation is performed. The position of each counterweight : ; in, Indicates the initial length of the mooring cable; This indicates the initial proportion coefficient of the preset deployment interval, with a value of 0.05, meaning that the counterweights are deployed starting from 5% of the cable length from the cable guide hole. This indicates the termination ratio coefficient of the preset deployment interval, with a value of 0.30, meaning the counterweight block deployment ends when 30% of the cable length is reached. Indicates the first One counterweight.

[0069] Optionally, the preset ratio cable length range is 5% to 30% of the cable length. The value is 0.05. The value is 0.30.

[0070] When the j Equivalent horizontal load borne by root mooring cable When the load is higher than the average load, it can Modify the cable guide hole side to increase pretension and restore stiffness near the cable guide hole.

[0071] In this way, by calculating the number, total volume and placement of the counterweights based on their total mass using S70, the counterweights can be rationally distributed along the mooring cable, effectively improving the stress distribution of the mooring cable, increasing the efficiency of restoring force utilization, and reducing stress concentration and fatigue risk in local cable sections.

[0072] S80: Recalculate the evaluation parameters based on the individual mass and position of the counterweight. The evaluation parameters include: mooring cable length, catenary restoring stiffness, guide hole tension, platform offset, and anchoring radius. If the changes in mooring cable length, catenary restoring stiffness, guide hole tension, platform offset, and anchoring radius are all less than the change threshold, the prediction result is considered to have converged. Otherwise, return to execute S40 to S80 until the changes in the evaluation parameters are all less than their respective change thresholds, and output the final mooring parameters.

[0073] Considering gravitational acceleration, the equivalent weight per unit length underwater is: .

[0074] The sections without counterweights are: , .

[0075] The recalculation of the mooring cable length includes: The first j The mooring cable is divided into several sections, the first... i Arc length and vertical drop They are respectively: ; ; in, Indicates the first j The horizontal tension component of the root cable; This represents the equivalent underwater weight per unit length of the mooring cable under conditions of gravitational acceleration. and Indicates the first i The horizontal position of the segment in the local catenary coordinate system; Indicates the first i The underwater equivalent unit length mass of each counterweight segment; This represents the mass per unit length of the mooring cable itself. For a mooring cable segment without counterweights, its equivalent mass per unit length is taken as... .

[0076] Calculate the new mooring cable length when the preset geometric constraints are met. : ; The preset geometric constraints include: ; ; in, This indicates the horizontal distance from the cable guide hole to the anchor point; This indicates the vertical distance from the cable guide hole to the anchor point.

[0077] It should be noted that the calculation methods for catenary recovery stiffness, cable hole tension, platform offset, and anchoring radius are existing technologies and will not be elaborated here.

[0078] The output mooring parameters include: mooring cable length, number of counterweights, mass of a single counterweight, volume of a single counterweight, position of each counterweight, tension in the cable guide hole, anchor end tension, maximum platform offset, and anchor radius. The output results can be used for construction design, model test scheme development, and initial parameter setting for numerical simulations.

[0079] In this way, the S80 recalculates the mooring cable length, catenary restoring stiffness, guide hole tension, platform offset, and anchor radius based on the counterweight mass and placement location. Iterative corrections are then made based on the changes in the evaluation parameters until each evaluation parameter meets the convergence condition. This reduces the number of repeated calculations, improves the efficiency of mooring parameter prediction, and yields the final mooring parameters that meet the design requirements.

[0080] In summary, the novel mooring parameter prediction method for semi-submersible floating wind turbine foundations provided in this disclosure can achieve the following technical effects: 1. By establishing the structural coupling relationship between the buoyancy ratio of the central buoy and the side buoys, the lever arm coefficient of the side buoys, the force transmission index of the inclined side columns, and the displacement amplification coefficient of the cable guide hole, and by incorporating the above structural parameters into the mooring parameter prediction process, the mooring parameters can reflect the influence of the floating foundation configuration on the restoring stiffness, the force on the cable guide hole, and the platform motion response. This improves the matching degree between the mooring parameter prediction results and the characteristics of the foundation structure, thereby helping to improve the overall stability of the floating foundation. 2. By first calculating the catenary recovery stiffness, guide hole tension, platform offset, and anchoring radius under the unbalanced state, and further determining the total mass, quantity, and placement of the counterweights based on the stiffness gap, the coordinated design of mooring cable length, counterweight parameters, and recovery capacity is achieved. This avoids relying solely on experience to repeatedly adjust the counterweight scheme, thus improving the design efficiency of the mooring system. 3. By establishing an iterative convergence mechanism based on the changes in evaluation parameters, the mooring cable length, catenary recovery stiffness, guide hole tension, anchor radius, and platform offset are cyclically corrected, so that the mooring parameters gradually converge to the results that meet the design requirements. This reduces the number of repeated trial calculations, lowers the computational load of parameter optimization, and improves the prediction efficiency of mooring parameters. 4. By performing unified coupled calculations of floating foundation structural parameters, environmental load parameters, and counterweight layout parameters, the joint prediction of multiple parameters such as mooring cable length, counterweight mass, counterweight position, and platform motion response is achieved. This improves the rationality and adaptability of mooring parameter configuration and provides reliable initial design parameters for the construction design, numerical simulation, and model testing of floating wind turbine foundations.

[0081] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0082] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A novel method for predicting mooring parameters of a semi-submersible floating wind turbine foundation, characterized in that, The novel semi-submersible floating wind turbine foundation includes: a central buoy, side buoys arranged around the central buoy, side post assemblies arranged around the side buoys, and a mooring system connected to the side post assemblies; wherein, the side post assembly includes: inclined side posts and vertical side posts, the bottom end of the inclined side posts is connected to the side buoys, and the bottom end of the vertical side posts is connected to the top end of the inclined side posts; the mooring system includes: a cable guide hole, anchor points, mooring cables, and multiple counterweights; The prediction method includes: S10, Calculate the buoyancy ratio between the central buoy and the side buoy and the lever arm coefficient of the side buoy based on the buoyancy of the central buoy, the buoyancy of the side buoy, and the lever arm of the side buoy; S20, based on the parameters of the inclined side post and the parameters of the cable guide hole, calculate the force transmission index of the inclined side post, and then calculate the structural coupling stability coefficient and the displacement amplification coefficient of each mooring cable. S30, calculate the initial length of each mooring cable based on the distance parameter between the cable guide hole and the anchor point, the structural coupling stability coefficient, and the displacement amplification coefficient of the cable guide hole; S40: Calculate the catenary recovery stiffness, guide hole tension, platform offset, and anchor radius of each mooring cable under unbalanced conditions; determine whether the catenary recovery stiffness, guide hole tension, platform offset, and anchor radius all meet the preset requirements; if yes, output the unbalanced solution; if no, execute S50. S50, calculate the stiffness gap of the catenary of each mooring cable based on the displacement amplification factor of the guide hole; S60, calculate the total mass of the counterweight based on the stiffness gap, the buoyancy ratio, the lever arm coefficient of the side float and the force transmission index of the inclined side column; S70, Calculate the number, total volume, and location of the counterweights based on their total mass; S80, recalculate the evaluation parameters based on the individual mass and position of the counterweight; the evaluation parameters include: mooring cable length, catenary restoring stiffness, guide hole tension, platform offset, and anchoring radius; until the change in the evaluation parameters is less than the change threshold, output the final mooring parameters.

2. The method of predicting mooring parameters for a new type of semi-submersible floating wind turbine foundation as claimed in claim 1, wherein, S10 includes: Calculate the buoyancy ratio : ； Calculate the lever arm coefficient of the side float. : ； in, This indicates the buoyancy of the side pontoons; This indicates the horizontal lever arm of the side buoy relative to the central buoy; The reference lever arm is set in advance; This indicates the buoyancy of the central pontoon.

3. The method for predicting mooring parameters of a novel semi-submersible floating wind turbine foundation according to claim 1, characterized in that, S20 includes: Calculate the force transmission index of the inclined side column : ； in, This indicates the inclination angle of the inclined side column; This indicates the projected distance in the horizontal plane between the cable guide hole and the center of the corresponding side float; This represents the projected length of the top and bottom ends of the inclined side column in the horizontal plane; , and All represent correction factors; Calculate the structural coupling stability coefficient : ； in, Indicates the moment of inertia of the platform's waterline surface; Indicates the moment of inertia of the reference waterline surface; Indicates the initial stability level; Indicates the reference initial stability height; The center height of the central pontoon; For the first j The height of each cable guide hole; , , , , and All represent weighting coefficients; Indicates the reference water depth; This indicates the buoyancy ratio; This represents the lever arm coefficient of the side buoy; Determine the displacement amplification factor of the cable guide hole. When the vertical position of the cable guide hole is within the lower 1 / 3 height range of the inclined side post from the bottom, and the horizontal lever arm of the corresponding side float relative to the central float... Greater than or equal to the reference lever arm hour, When the vertical height of the cable guide hole Greater than or equal to the center height of the central pontoon Or the horizontal projection distance between the cable guide hole and the axis of the center column is greater than or equal to the horizontal lever arm of the side float relative to the central float. When it is 1.05 times, .

4. The method for predicting mooring parameters of a novel semi-submersible floating wind turbine foundation according to claim 1, characterized in that, S30 includes: Calculate the initial length : ； in, This represents the relaxation coefficient of the cable length after structural correction; This indicates the horizontal distance from the cable guide hole to the anchor point; Indicates the vertical distance from the cable guide hole to the anchor point; satisfy: ； in, Represents the basic relaxation coefficient; Indicates the reference environmental load; Indicates the first j The equivalent horizontal load borne by the root mooring cable; This represents the coupling stability coefficient of the structure; This represents the displacement amplification factor of the cable guide hole; , and All of these represent correction factors.

5. The method for predicting mooring parameters of a novel semi-submersible floating wind turbine foundation according to claim 1, characterized in that, The S50 includes: Calculate the target recovery stiffness : ； in, Indicates the first j The equivalent horizontal load borne by the root mooring cable; Indicates the platform's allowed horizontal offset; This represents the displacement amplification factor of the cable guide hole; Calculate the stiffness gap based on the target recovery stiffness and the catenary recovery stiffness. : ； in, This indicates the catenary recovery stiffness of the mooring cable under unbalanced conditions.

6. The method for predicting mooring parameters of a novel semi-submersible floating wind turbine foundation according to claim 5, characterized in that, The S60 includes: ； in, This indicates the total mass of the counterweight; Indicates when Take when greater than 0 Otherwise, take 0; The notch represents the stiffness; Indicates the platform's allowed horizontal offset; Represents gravitational acceleration; Indicates the density of seawater; This indicates the density of the counterweight material; Indicates the efficiency of counterweight restoring force transmission; Among them, the counterweight restoring force transmission efficiency satisfy: ； in, This indicates the buoyancy ratio; This represents the lever arm coefficient of the side buoy; This indicates the force transmission index of the inclined side column; This represents the displacement amplification factor of the cable guide hole; , , , and All of these represent calibration coefficients.

7. The method for predicting mooring parameters of a novel semi-submersible floating wind turbine foundation according to claim 1, characterized in that, The S70 includes: Calculate the number of the counterweights. : ； in, This indicates the total mass of the counterweight; Indicates the maximum permissible mass of a single counterweight; Calculate the total volume of the counterweight. : ； in, This indicates the density of the counterweight material; Multiple counterweights are placed within a predetermined proportion of cable length near the cable guide hole, and the positions of the counterweights are calculated. : ； in, Indicates the initial length of the mooring cable; Indicates the initial proportional coefficient of the preset deployment interval; Indicates the termination ratio coefficient of the preset deployment interval; Indicates the first One counterweight.

8. The method for predicting mooring parameters of a novel semi-submersible floating wind turbine foundation according to claim 1, characterized in that, In step S80, recalculating the mooring cable length includes: The first j The mooring cable is divided into several sections, the first... i Arc length and vertical drop They are respectively: ； ； in, Indicates the first j The horizontal tension component of the root cable; This represents the equivalent underwater weight per unit length of the mooring cable under conditions of gravitational acceleration. and Indicates the first i The horizontal position of the segment in the local catenary coordinate system; Calculate the new mooring cable length when the preset geometric constraints are met. : ； The preset geometric constraints include: ； ； in, This indicates the horizontal distance from the cable guide hole to the anchor point; This indicates the vertical distance from the cable guide hole to the anchor point.

9. A method for predicting mooring parameters of a novel semi-submersible floating wind turbine foundation according to any one of claims 1 to 8, characterized in that, The mooring parameters include: the length of the mooring cable, the number of counterweights, the mass of a single counterweight, the volume of a single counterweight, the position of each counterweight, the tension of the cable guide hole, the tension of the anchor end, the maximum platform offset, and the anchoring radius.

10. A novel semi-submersible floating wind turbine foundation, characterized in that, A method for predicting mooring parameters for a novel semi-submersible floating wind turbine foundation according to any one of claims 1 to 9; comprising: The central pontoon is a hollow cylindrical floating structure with a polygonal horizontal cross-section. The bottom of the central column is connected to the top of the central pontoon; Side buoy assembly, hollow and connected circumferentially to the central buoy; A side post assembly is provided circumferentially along the side of the float assembly, and the bottom of the side post assembly is connected to the side of the side float assembly; A support assembly is connected between the top of the side column assembly and the outer wall of the central pontoon; A mooring system connected to the side pillar assembly.

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