Wind Turbine Blade Tip Thickness Shift for Noise Reduction

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Solution Overview

Problem

Wind turbine blades face challenges in improving aerodynamic performance and reducing noise without increasing blade diameter, particularly in the blade-tip region where tip speed is high, leading to inefficiencies and noise generation.

Innovation Solution

The maximum-blade-thickness position in the blade-tip region is shifted closer to the leading edge compared to the blade-body region, with specific dimensional ranges for radial positions and chord lengths, enhancing lift coefficient and reducing boundary layer thickness to improve aerodynamic performance and noise reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the blade diameter is increased to increase power generation, then the power output increases, but the aerodynamic load and equipment size increase causing cost increase

Engineering Contradiction:
Improvepower outputVSAvoidequipment weight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The patent applies different maximum blade thickness positions at different radial locations. Specifically, in the blade-tip region (dimensionless radial position 0.6-1.0), the maximum blade thickness position is set closer to the leading edge (25-40% chord length) compared to the blade-body region. This local differentiation optimizes aerodynamic performance at the blade tip where tip speed is highest, thereby reducing aerodynamic noise and improving efficiency without requiring an overall increase in blade diameter

Inventive Principle:
Principle #3Local quality

2Power

If the blade diameter is increased to increase power generation, then the power output increases, but the aerodynamic noise increases due to increased tip speed

Engineering Contradiction:
Improvepower outputVSAvoidaerodynamic noise
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The patent specifically addresses the blade-tip region where tip speed is highest and noise generation is most significant. By positioning the maximum blade thickness closer to the leading edge in this region (25-40% chord length from leading edge), the patent optimizes the aerodynamic characteristics at the noise-critical location, reducing vortex formation and noise without compromising overall power generation capability

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent preemptively addresses noise generation by optimizing the blade tip geometry before the blade enters high-speed rotation. The specific configuration of maximum thickness position closer to the leading edge at the blade tip creates more favorable airflow conditions from the outset, preventing excessive noise generation rather than attempting to mitigate it after the fact

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the maximum-blade-thickness position is shifted closer to the leading edge in the blade-tip region, then aerodynamic performance improves and noise reduces, but the structural configuration becomes more complex

Engineering Contradiction:
Improveaerodynamic performanceVSAvoidblade structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements a targeted geometric modification only in the blade-tip region (dimensionless radial position 0.6-1.0) where it is most needed for noise reduction, while maintaining conventional thickness distribution in the blade-body region. This localized approach improves aerodynamic performance without requiring a complete redesign of the entire blade structure, thereby limiting the increase in manufacturing complexity

Inventive Principle:
Principle #3Local quality

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 enhances aerodynamic performance and reduces noise effectively in the blade-tip region, maintaining structural integrity while increasing power output and reducing aerodynamic noise without enlarging the blade diameter.

Implementation Method 1

a lift coefficient for the angle-of-attack corresponding to a maximum lift-to-drag ratio (lift/drag) of an airfoil (blade cross-section)

Methodology Applied
Scientific EffectAerodynamic lift: Aerofoil

Implementation Method 2

the actual upper limit is approximately 0.5 due to the influence of the wind turbine wake and air resistance of the blades

Methodology Applied
Scientific EffectAir resistance: Drag

Implementation Method 3

generates power by converting the rotational force to electric power

Methodology Applied
Scientific EffectMechanical energy conversion:

Data Source

PatentEP2682602B1Wind turbine blade and wind-powered electricity generator provided with same
Publication Date: 2015.06.10 MITSUBISHI HEAVY IND LTD
  • EP2682602B1 patent drawingFigure 1
  • EP2682602B1 patent drawingFigure 2
  • EP2682602B1 patent drawingFigure 3

AI summary

Provided is a wind turbine blade that can improve aerodynamic performance in a blade-tip region and reduce aerodynamic noise. A wind turbine blade includes a blade body having a chord length that decreases from a blade root side to a blade tip side, wherein the blade body includes a blade-tip region in which a dimensionless radial position is within the range of 0.6 to 1.0, inclusive, the dimension less radial position being the ratio of radial position to blade radius (1/2 of a blade diameter), and a blade-body region in which the dimensionless radial position is smaller than 0.6, and wherein a maximum-blade-thickness position (L1) of a blade cross-section in the blade-tip region is closer to a leading edge (9) than a maximum-blade-thickness position (L1) of a blade cross-section in the blade-body region.