Wind Turbine Rotor Blade Serrated Trailing Edge Noise Reduction
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Solution Overview
Problem
Conventional wind turbine rotor blades generate significant noise at the trailing edge, particularly when the angle between the airflow and the trailing edge is 90 degrees, leading to increased noise levels that can exceed acceptable thresholds in residential areas.
Innovation Solution
The rotor blade incorporates serrations along its trailing edge with comb elements and ridges arranged parallel to the chordwise direction, where the comb elements are placed between the serrations to further reduce noise, enhancing the noise reduction capabilities beyond traditional serrated designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional smooth trailing edges are used, then manufacturing is simple, but noise generation is high at 90-degree flow angles
Solution Approach 1:
The trailing edge is segmented into multiple serrations (teeth) arranged in a specific pattern, dividing the continuous edge into discrete elements that reduce noise through flow manipulation and interference patterns
Solution Approach 2:
The trailing edge combines multiple structural elements (serrations, comb elements, ridges) into a composite configuration that integrates different noise reduction mechanisms into a single functional structure
2Object-generated harmful factors
If serrations are added to the trailing edge, then noise is reduced, but device complexity increases
Solution Approach 1:
Comb elements are nested within the spaces between serration teeth, creating a multi-layered structure where smaller elements are positioned within the gaps of larger elements to maximize space utilization and noise reduction efficiency
Solution Approach 2:
Multiple noise reduction features (serrations, comb elements, and ridges) are merged into a single integrated trailing edge structure that works synergistically to reduce noise across different flow conditions
3Object-generated harmful factors
If comb elements are placed between serration teeth, then noise reduction is enhanced, but manufacturing complexity increases
Solution Approach 1:
Comb elements are selectively positioned only in specific regions between certain serration teeth where they provide the most effective noise reduction, rather than uniformly distributing them across the entire trailing edge
4Object-generated harmful factors
If ridges are added for flow manipulation, then noise is further reduced, but device complexity increases
Solution Approach 1:
Ridges are positioned upstream of the serrations to pre-condition the flow before it reaches the noise-generating trailing edge, manipulating the airflow in advance to reduce turbulence and noise generation at the serrated section
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 significantly reduces noise at the trailing edge, achieving a high and unexpected level of noise reduction, making it suitable for wind turbines installed near residential areas.
Implementation Method 1
mixing of the airflow from suction and pressure side of the rotor blade past the trailing edge, which is also referred to as flow recovery, can lead to turbulence which can also adversely impact the noise which is generated by the rotor blade
Implementation Method 2
Due to the serrations, the angle between the mean flow direction of the airflow and the trailing edge is modified. This modification may significantly reduce the generated noise at the trailing edge
Data Source
AI summary
A rotor blade for a wind turbine, wherein the rotor blade includes serrations along at least a portion of the trailing edge section of the rotor blade is provided. The serrations include a first tooth and at least a second tooth, wherein the first tooth is spaced apart from the second tooth. Furthermore, the area between the first tooth and the second tooth is at least partially filled with a plurality of comb elements, wherein the comb elements are arranged substantially parallel to each other and in substantially chordwise direction of the rotor blade such that generation of noise in the trailing edge section of the rotor blade is reduced. The rotor blade is further characterized in that it includes a plurality of ridges including a first ridge and at least a second ridge for manipulating an airflow which is flowing along the ridges.