Toroid Liquid Damper With Vertical Ribs for Low-Frequency Tower Oscillation
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Solution Overview
Problem
Conventional liquid dampers for wind turbine towers face limitations in effectively damping low-frequency oscillations, particularly due to the rotational mode of liquid in toroid-shaped dampers, which reduces their damping effectiveness and can cause structural damage during installation and operation, and they are not suitable for very large wind turbines with low natural frequencies.
Innovation Solution
A toroid damper design featuring a housing with horizontal annuli, cylindrical walls, and vertical ribs that disrupt liquid motion, allowing for effective damping of elliptical tower oscillations and accommodating a larger operational liquid volume to target low natural frequencies, with adjustable bulkheads for varying operational conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a toroid-shaped damper is used to accommodate cable bundles, then the damper can be installed in the tower, but the liquid enters a rotational mode during circular tower oscillations, causing the damping effect to be absent
Solution Approach 1:
The toroid damper is segmented by adding internal baffle walls that divide the liquid chamber into separate compartments. This segmentation prevents the liquid from rotating as a single body, eliminating the rotational mode and restoring damping effectiveness while maintaining the toroid shape for cable accommodation
Solution Approach 2:
Baffle walls are introduced as intermediary structures within the liquid chamber. These baffles act as mediators that disrupt the rotational motion of the liquid without interfering with the overall toroid shape, allowing the liquid to dampen tower oscillations effectively
2Reliability
If the damper is configured for low-frequency oscillations of assembled wind turbines, then it can damp operational tower oscillations, but the tower incurs structural damage during assembly and transport stages when the natural oscillation frequency is higher
Solution Approach 1:
The damper system is made dynamically adjustable by incorporating variable mass capabilities. Ballast tanks can be filled or emptied to change the liquid mass, thereby adjusting the natural frequency of the damper to match the tower's oscillation frequency at different stages (assembly/transport vs. operational), preventing structural damage while maintaining damping effectiveness
Solution Approach 2:
The mass parameter of the liquid in the damper is made variable through ballast systems. By changing the liquid mass, the natural frequency of the damper can be tuned to match different operating conditions, allowing effective damping during both assembly/transport (higher frequency) and operational phases (lower frequency)
3Ease of operation
If the width of the damper is limited to one side of the cable bundle and ladder, then the damper can be installed in the tower, but there is a lower limit to tower frequency that can be damped effectively
Solution Approach 1:
The damper adopts a toroid (doughnut-shaped) geometry instead of a conventional cylindrical or rectangular shape. This curved, ring-like structure allows the damper to wrap around the cable bundle and ladder in the center of the tower, maximizing the use of available space and increasing the liquid volume for damping low-frequency oscillations effectively
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
The toroid damper design enhances damping performance across a wider range of frequencies, including low natural frequencies, reduces structural damage, and simplifies installation by effectively damping tower oscillations during transport and operation, thereby extending the lifespan of wind turbine components.
Implementation Method 1
The liquid tends to slosh back and forth in the opposite direction as the tower
Implementation Method 2
a sufficiently large quantity of liquid can be effective at damping tower oscillations
Implementation Method 3
the liquid damper comprises an arrangement of vertical ribs mounted to a cylindrical wall of the damper
Data Source
AI summary
A liquid damper for a wind turbine tower includes a damper housing formed from a horizontal lower annulus, a horizontal upper annulus, an essentially cylindrical outer vertical wall and an essentially cylindrical inner vertical wall, wherein the outer diameter of the damper corresponds to the interior diameter of the tower; an operational volume of liquid contained in the damper; and an arrangement of vertical ribs mounted to a vertical wall of the damper. Further provided is a method of assembling a wind turbine.