Wind Turbine Rotor Blade Trailing Edge for Noise Reduction
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Solution Overview
Problem
Wind turbines emit perceptible noise due to aerodynamic effects at the trailing edges of rotor blades, leading to reduced operational efficiency and economic output when noise reduction measures are implemented, such as lowering rotational speed.
Innovation Solution
The introduction of a rotor blade design featuring profile elements with specific cross-sectional characteristics, including local minima and maxima, which are attached to the trailing edge to modify sound radiation patterns and break up turbulent structures, combining the concepts of trailing edge serrations and finlets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the rotational speed of the wind turbine is reduced to reduce trailing edge noise, then noise emissions are reduced, but the system's output and economic efficiency are reduced
Solution Approach 1:
The trailing edge is segmented into multiple discrete elements (serrations or finlets) rather than a continuous smooth edge. This segmentation breaks up the coherent turbulent structures that generate noise, allowing noise reduction without sacrificing rotational speed or power output.
Solution Approach 2:
The invention transitions from a two-dimensional trailing edge profile to a three-dimensional structure by adding spanwise elements (serrations extending along the span or finlets protruding from the trailing edge). This dimensional change enables noise reduction through spatial distribution of flow control without affecting the chordwise aerodynamic performance.
2Object-affected harmful factors
If trailing edge serrations or finlets are used to reduce noise, then trailing edge noise is reduced, but device complexity increases
Solution Approach 1:
The invention combines the noise reduction function with the existing trailing edge structure by integrating serrations or finlets directly into the airfoil geometry. This merging approach adds noise control capability without requiring separate, complex attachment systems or additional structural components.
Solution Approach 2:
The serrated or finlet-equipped trailing edge structure serves multiple functions: it reduces trailing edge noise while maintaining aerodynamic performance for power generation. The same structural modification provides both noise control and sustained aerodynamic efficiency without requiring separate systems.
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 proposed design reduces trailing edge noise by diffusing sound radiation, allowing for higher operational efficiency and economic output without the need to reduce rotational speed, and can be easily retrofitted onto existing systems.
Implementation Method 1
The at least one profile element 200 breaks up turbulent structures in the boundary layer
Implementation Method 2
the at least one profile element 200 modifies the directional characteristics of the dominant sound sources in such a way that the sound source radiates more diffusely
Data Source
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AI summary
The invention relates to a rotor blade (108) of a wind turbine (100), a wind turbine (100) with a rotor blade (108), and a method for optimizing a rotor blade (108). In particular, the invention relates to a rotor blade (108) of a wind turbine (100), wherein the rotor blade has a leading edge (112), a trailing edge (114), a suction side (118), and a pressure side (120) and extends in a longitudinal direction between a root end and a tip end, wherein a direct connection between the leading edge (112) and the trailing edge (114) is referred to as the chord line and its length is referred to as the chord line, wherein the rotor blade (108) has at least one airfoil element (200).wherein the at least one profile element (200) is arranged with a proximal section (214) on a trailing edge region (116) adjacent to the trailing edge (114) and projects with a distal section (216) from the trailing edge (114) with a projection direction (122) which is oriented substantially parallel to the direction of the profile depth, wherein the at least one profile element (200) has a profile element thickness in a direction perpendicular to the projection direction (122), wherein the at least one profile element (200) has a pressure-side profile side (226) associated with the pressure side (120) and a suction-side profile side (218) associated with the suction side (118), wherein the at least one profile element (200) has a cross-section substantially orthogonal to the projection direction (122), characterized in that the cross-section of the at least one profile element (200) has at least a local minimum of the profile element thickness,where the profile element thickness in the cross-section on both sides of the local minimum has a larger value.