Wind Turbine Blade Back Shape for Noise Reduction
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Solution Overview
Problem
Wind turbine blades face challenges in increasing power generation while minimizing aerodynamic noise and aerodynamic load, as existing designs often prioritize efficiency over noise reduction and may lead to increased costs due to larger sizes and weights.
Innovation Solution
The wind turbine blade design incorporates a specific back shape with defined derivative amounts (dY/dX) to reduce turbulence boundary layer thickness, featuring a first region with a primary change, a second region with a smaller change, and a third region with a larger change, forming an S-shaped curve, which reduces aerodynamic noise by minimizing blade surface flow velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If blade diameter is enlarged to increase power generation, then output power increases, but aerodynamic load increases which increases device sizes and weights
Solution Approach 1:
The blade design applies local quality by varying the chord length distribution along the blade span and optimizing the blade profile shape at different radial positions. The blade has different geometric characteristics at different locations - thicker and more curved near the root for strength, thinner and more streamlined near the tip for reduced drag, creating locally optimized performance that reduces overall aerodynamic load while maintaining power generation
Solution Approach 2:
The invention changes key geometric parameters including blade chord length, blade profile thickness ratio, and blade twist angle along the span. By optimizing these parameters - particularly setting the root chord length to 5-15% of blade diameter and using specific airfoil sections - the blade achieves reduced aerodynamic load while maintaining or improving power output
2Power
If blade efficiency is increased to improve power generation, then output power increases, but aerodynamic noise increases due to turbulence and wake effects
Solution Approach 1:
The blade profile employs curved and streamlined geometries throughout - the airfoil cross-sections are smoothly curved, the blade twists gradually along the span, and the trailing edge is rounded rather than sharp. These curved forms promote smooth airflow attachment and reduce turbulent wake formation, thereby reducing aerodynamic noise while maintaining efficient lift generation
Solution Approach 2:
The blade design incorporates dynamic optimization by adjusting the twist angle and chord length distribution to match varying flow conditions along the blade span. Different sections of the blade are optimized for different local flow velocities and angles of attack, creating a dynamically adapted geometry that reduces turbulence and noise across the entire operating range
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 design effectively reduces aerodynamic noise by limiting turbulence boundary layer thickness, maintaining efficiency while preventing increases in aerodynamic load, thus optimizing power generation and reducing operational costs.
Implementation Method 1
a blade profile shape controlling a boundary layer flow
Implementation Method 2
an adverse effect of the turbulence on the blade back side
Data Source
AI summary
When a distance from a front edge along a blade chord line is represented by X and a distance from the blade chord line to a blade back side is represented by Y, a blade back shape of a wind turbine blade includes a first region extending from the maximum blade thickness position toward the rear edge with dY/dX as a primary derivative amount of Y to X decreasing by a first amount of change, a second region on a side of the rear edge of the first region and extending toward the rear edge with dY/dX having a second amount of change smaller than the first amount of change, and a third region on the side of the rear edge of the second region and connected to the rear edge with dY/dX decreasing by a third amount of change larger than the second amount of change.