Rotor Blade Airflow Wraps for Standstill Vibration Mitigation
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Solution Overview
Problem
Wind turbines experience damaging vortex-shedding and stall-induced vibrations during standstill due to wind flow, which existing methods struggle to mitigate effectively, especially when rotor blade adjustments are not possible.
Innovation Solution
An apparatus comprising a positioning element wrapped around the rotor blade with airflow modifying elements, such as streamers, fences, or inflatable cells, secured by a cord or sleeve to disrupt airflow and prevent vortex formation, thereby reducing vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If rotor blade pitch adjustment is used to mitigate vibrations, then vortex-shedding vibrations are reduced, but the system becomes complex and adjustments may not be possible during maintenance or failure conditions
Solution Approach 1:
The airflow modifying element is pre-installed on the rotor blade before the turbine enters standstill conditions. This preliminary action ensures vibration mitigation is already in place when the turbine parks, eliminating the need for real-time pitch adjustments during maintenance or failure conditions.
Solution Approach 2:
The airflow modifying element acts as an intermediary device between the wind flow and the rotor blade, physically disrupting vortex formation and modifying airflow characteristics without requiring active control systems or pitch mechanism adjustments.
2Adaptability or versatility
If the wind direction shifts while the rotor blade is fixed, then the angle of attack increases, but this causes flow separation and stall-induced vibrations
Solution Approach 1:
The airflow modifying element is positioned upstream on the rotor blade to preemptively disrupt vortex formation and modify flow characteristics before the wind can cause flow separation. This preliminary anti-action prevents stall conditions even when the blade remains fixed and wind direction shifts.
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 apparatus effectively mitigates vortex-shedding and stall-induced vibrations by disrupting airflow and preventing lift, reducing the likelihood of damaging oscillations during maintenance or idling conditions.
Implementation Method 1
the wind attempts to flow around the slender structure of the rotor blade and form a vortex at the point where the flow separates from the rotor blade. Depending on the relative angle between the wind and the rotor blade, a vortex-shedding phenomenon may occur where the vortices form on the edges of the blade and are shed in a rhythmic pattern
Implementation Method 2
at least one positioning element located between a blade tip section and a blade root section thereof. The positioning element(s) is adapted for wrapping around at least a portion of the rotor blade
Data Source
Figure 1
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Figure 3B~4
AI summary
An apparatus for mitigating vortex-shedding vibrations or stall-induced vibrations on one or more rotor blades of a wind turbine during standstill includes at least one positioning element located between a blade tip section and a blade root section thereof. The positioning element is adapted for wrapping around at least a portion of the rotor blade. The apparatus also includes at least one airflow modifying element coupled to the positioning element and defining a height relative to a surface of the rotor blade. Additionally, the apparatus includes at least one securing element operably coupled to the positioning element for temporarily securing the airflow modifying element to the rotor blade.