Wind Turbine Leading Edge Protector With Boundary-Layer Irregularities
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Solution Overview
Problem
Existing leading edge protectors for wind turbine blades suffer from corrosion and aerodynamic inefficiencies due to thickness-induced turbulent flow transitions, leading to reduced efficiency and increased erosion.
Innovation Solution
A leading edge protector with a substantially constant thickness and irregularities such as protrusions or recesses on its surface to energize the boundary layer, delaying flow separation and improving aerodynamic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If leading edge protectors with increased thickness are used to reduce corrosion, then the lifetime of the leading edge is extended, but the aerodynamic efficiency decreases due to uncontrolled transition from laminar to turbulent flow
Solution Approach 1:
The invention changes the geometric parameters of the leading edge protector by introducing irregularities (protrusions and recesses) on its outer surface. These irregularities have specific height ranges (0.1-10mm protrusions, 0.1-5mm recesses) and spacing patterns that control boundary layer behavior. This parameter modification allows the protector to maintain constant thickness for corrosion resistance while the surface irregularities energize the boundary layer to delay flow separation, thus maintaining aerodynamic efficiency despite the protective thickness.
Solution Approach 2:
The invention applies local quality by creating non-uniform surface features (protrusions and recesses) only in specific regions of the leading edge protector's outer surface. These localized irregularities are positioned upstream from the trailing end and have varying heights and spacing patterns. This local modification allows the boundary layer to be energized at critical locations without requiring changes to the overall thickness of the protector, thus resolving the contradiction between thickness-induced corrosion resistance and aerodynamic performance.
2Object-affected harmful factors
If leading edge protectors are used to protect against abrasive particles, then blade erosion is reduced, but the lift coefficient flattens and stall occurs at smaller angles of attack
Solution Approach 1:
The invention applies preliminary action by introducing surface irregularities (protrusions and recesses) on the leading edge protector that proactively energize the boundary layer before the airflow reaches the trailing end of the protector. This preliminary energization occurs at the upstream location where the irregularities are positioned, preventing flow separation from occurring in the first place. As a result, the lift coefficient maintains its normal curve shape and stall is delayed to higher angles of attack, preserving power production efficiency while the protector continues to shield against abrasive particles.
3Ease of manufacture
If constant thickness leading edge protectors are used to simplify manufacturing, then production cost is reduced, but flow separation occurs at the trailing end
Solution Approach 1:
The invention applies segmentation by dividing the leading edge protector's outer surface into multiple zones with different characteristics: a main body portion with constant thickness for manufacturing simplicity, and a surface layer with irregularities (protrusions and recesses) for aerodynamic control. This segmentation allows the bulk of the protector to be manufactured with simple constant thickness geometry, while only the outer surface requires the more complex irregularity features. The result is that manufacturing remains relatively simple while flow separation is prevented through the segmented surface structure.
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
Enhances lift and reduces drag by re-energizing the boundary layer, thereby increasing the efficiency and reducing erosion of wind turbine blades.
Implementation Method 1
a laminar boundary layer would be arranged around a blade without a LEP for a significant part of the chord
Implementation Method 2
the flow separates from the profile. The separation causes a wake of turbulent flow
Implementation Method 3
an uncontrolled transition from laminar to turbulent flow
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Leading edge protectors for a wind turbine blade are disclosed. The leading edge protectors are configured to at least partially cover a blade leading edge section. The leading edge protectors comprise a main body having a substantially constant thickness and having a trailing end. The leading edge protectors further comprise a plurality of irregularities arranged on an outer surface of the main body upstream from the trailing end and configured to energize a boundary layer. Wind turbines comprising such leading edge protectors are also disclosed.