Spar-Type Floating Wind Facility Yaw Stability
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Solution Overview
Problem
Spar-type floating offshore wind power generation facilities face issues with reduced power generation efficiency due to tilting of the tower, increased rotary movement (yaw) around a vertical axis, potential contact of boats and ships with mooring cables, and high costs associated with assembly and reinforcement to prevent bending stress during assembly and transportation.
Innovation Solution
A spar-type floating offshore wind power generation facility with a downwind-type windmill configuration, where the rotation axis is tilted upward, and mooring points are set below the sea surface and above the center of gravity, incorporating a composite floating body structure with split precast cylindrical concrete and steel components, and yaw-suppressing fins to reduce yaw movement and enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the tower is allowed to tilt freely under wind load, then the windmill can operate with optimal blade angle, but the power generation efficiency decreases due to tower tilting
Solution Approach 1:
The patent applies preliminary anti-action by pre-configuring the tower with an upward tilt angle (5-10 degrees) relative to the horizontal plane. This preliminary inclination counteracts the natural downward tilt caused by wind pressure, maintaining the blade's optimal attack angle and preventing power generation efficiency loss.
2Ease of manufacture
If the mooring cable is positioned at sea surface level, then it is easier to connect, but boats and ships may contact the mooring cable causing safety issues
Solution Approach 1:
The patent resolves the contradiction by moving the mooring cable connection point from the horizontal plane (sea surface level) to the vertical dimension (below sea surface). The mooring cable extends from a subsea anchorage point to the tower base, eliminating vessel contact risk while maintaining connection functionality through vertical positioning.
3Stability of the object's composition
If the floating body uses a single large concrete structure, then it has good stability, but it is difficult to transport and assemble
Solution Approach 1:
The patent applies segmentation by dividing the floating body into multiple modular concrete segments that can be manufactured, transported, and assembled separately. These segments are then connected using PC steel materials to form the complete floating structure, combining the stability of large concrete structures with the ease of modular assembly.
Solution Approach 2:
The patent uses composite materials by combining concrete segments with PC (prestressed concrete) steel materials at the connection points. This composite construction maintains the stability benefits of concrete while incorporating the tensile strength and flexibility of steel, enabling modular assembly of large-scale floating structures.
4Stability of the object's composition
If the floating body uses a single large structure, then it has good stability, but bending stress occurs during assembly and transportation
Solution Approach 1:
The patent segments the floating body into smaller concrete sections that experience reduced bending stress during handling and transportation. Each segment can be managed with appropriate lifting equipment, and the modular design prevents excessive bending moments that would occur with a single large monolithic structure.
Solution Approach 2:
The patent applies preliminary action by pre-assembling and pre-stressing the concrete segments with PC steel materials before final installation. This preliminary assembly and prestressing creates a structurally sound composite unit that can resist bending stresses during subsequent assembly and operational phases.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances power generation efficiency, minimizes contact risks with mooring cables, and reduces assembly complexity and costs by distributing loads effectively and providing increased resistance to bending stress.
Implementation Method 1
a plurality of outer cables (31) with a tensioning force introduced thereinto are circumferentially wound in axial direction around the outer circumference of the precast cylindrical bodies (12)
Implementation Method 2
a floating body (2), a mooring cable (3), a tower (4), and a windmill (5) installed at the top of the tower (4)
Data Source
Figure 1
Figure 2
Figure 3(A)~3(C)
AI summary
There is provided a spar-type floating offshore wind power generation facility that suppresses a reduction in power generation efficiency caused by tilting of a tower, suppresses rotational motion (yaw motion) around a vertical axis, prevents a ship from coming into contact with a mooring cable, and, at the same time, appropriately holds the tilted posture state of the tower. A floating offshore wind power generation facility 1 includes a floating body 2, a mooring cable 3, a tower 4, and a windmill 5 installed at the top of the tower 4, the windmill 5 including a nacelle 6 and a plurality of blades 7. The rotation axis of the windmill 5 has a predetermined upward angle to avoid contact between the blades 7 and the tower 4, and the windmill 5 is of a downwind type in which the blades 7 are attached to the leeward side of the nacelle 6 and installed with the back surfaces of the blades 7 facing windward, and the mooring point of the mooring cable 3 to the floating body 2 is set at a position below the surface of the sea and higher than the center of gravity of the floating body 2.