Tunable Blade Mass Damper for Locked-Rotor Wind Vibration
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Solution Overview
Problem
Wind turbine blades experience aero-elastic instabilities such as vortex-induced and stall-induced vibrations when the rotor is locked or idling, leading to potential blade damage, and existing solutions like aerodynamic devices increase installation and removal costs.
Innovation Solution
A tunable mechanical mass damper is attached to the rotor blades, comprising a flywheel and rotation damper system that automatically adjusts to excitation frequencies, using a counter-torque mechanism to mitigate vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If aerodynamic devices are attached to the blades to reduce vortices and increase damping, then vibrations are reduced, but installation and removal costs increase
Solution Approach 1:
The patent extracts the vibration reduction function from complex aerodynamic devices and implements it through a simpler mass damper system. The mass damper is a self-contained device that attaches to the blade and provides damping without requiring the complex aerodynamic structures, thereby reducing installation and removal costs while maintaining vibration reduction effectiveness.
Solution Approach 2:
The mass damper is designed as a relatively simple, cost-effective device that can be easily installed and removed. Unlike permanent aerodynamic modifications, the mass damper can be attached temporarily during maintenance or idling periods and removed when not needed, reducing long-term costs and simplifying blade maintenance.
2Object-affected harmful factors
If the pitch angle is set to 90 degrees to reduce loads on locked rotor blades, then some vibrations are reduced, but the locking pin suffers higher loads and not all vibrations are avoided
Solution Approach 1:
The mass damper acts as an intermediary element between the blade structure and the vibration forces. Instead of relying solely on pitch angle adjustment, the mass damper provides additional damping that works in conjunction with the pitch system, allowing for reduced locking pin loads while maintaining effective vibration control across a broader range of conditions.
3Power
If wind turbine blades are made increasingly longer to capture more wind energy, then power generation increases, but blades become more flexible and prone to aero-elastic instabilities
Solution Approach 1:
The mass damper is designed with dynamic characteristics that allow it to adapt to the varying vibration frequencies of longer, more flexible blades. The damper's natural frequency can be tuned to match the blade's eigen frequencies, providing effective damping across different operating conditions and wind speeds, thereby maintaining stability in longer blade designs.
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
Effectively reduces vibrations and loads on the blades during non-operational conditions, enhancing safety and reducing installation and operational costs without requiring additional aerodynamic devices.
Implementation Method 1
The mass damper includes a movable mass component that is responsive to changes in vibrations or oscillations induced in the rotor blades
Implementation Method 2
A tunable mechanical mass damper is attached to the rotor blades, comprising a flywheel and rotation damper system that automatically adjusts to excitation frequencies, using a counter-torque mechanism to mitigate vibrations
Data Source
AI summary
A system and method are provided for reducing vibrations and loads in one or more rotor blades on a rotor hub of a wind turbine when the rotor hub is in a locked or idling condition. A mass damper is attached at a fixed location on one or more of the rotor blades and is maintained on the rotor blades during the locked or idling condition of the rotor hub. The mass damper includes a movable mass component that is responsive to changes in the vibrations or oscillations induced in the rotor blades during the locked or idling condition of the rotor hub.