Wind Turbine Blade Flow Guiding Device for Lift and Drag Reduction

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Solution Overview

Problem

Wind turbine blades face challenges in aerodynamic performance due to the large surface area and structural loads, particularly in the root and transition regions, which affect energy production and mounting efficiency.

Innovation Solution

A flow guiding device with a front surface angled towards the oncoming airflow is integrated into the blade, creating an air pocket and guiding airflow around it, thereby increasing lift and reducing drag in these regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the blade has a large surface area to generate sufficient lift, then energy production is improved, but structural loads and storm loads increase

Engineering Contradiction:
Improveenergy productionVSAvoidstructural loads
Core Design Contradiction:
PowerVSForce

Solution Approach 1:

The patent applies parameter changes by modifying the blade geometry in the root and transition regions. Specifically, the blade width is reduced and the cross-section is optimized in these regions while maintaining the necessary lift-generating capabilities. This allows the blade to produce sufficient energy with a smaller overall surface area, thereby reducing structural loads and storm loads without significantly compromising power generation.

Inventive Principle:
Principle #35Parameter changes

2Strength

If the blade has a wide root region for structural strength, then mounting safety is improved, but aerodynamic performance deteriorates due to drag

Engineering Contradiction:
Improvemounting safetyVSAvoiddrag
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The patent applies local quality by optimizing different regions of the blade with different geometric characteristics. The root region has a narrower width and optimized cross-section to reduce drag, while the airfoil region maintains the necessary width and shape for lift generation. The transition region smoothly connects these two zones. This localized optimization allows the blade to have sufficient mounting strength while minimizing aerodynamic drag in the root region.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If the blade has a circular cross-section in the root region for ease of mounting, then mounting efficiency is improved, but aerodynamic performance deteriorates

Engineering Contradiction:
Improvemounting efficiencyVSAvoidaerodynamic performance
Core Design Contradiction:
Ease of manufactureVSPower

Solution Approach 1:

The patent applies segmentation by dividing the blade into distinct functional regions: a root region optimized for mounting with a circular or near-circular cross-section, a transition region with gradually changing geometry, and an airfoil region optimized for aerodynamic performance. This segmentation allows each region to be optimized for its specific function - the root region for easy mounting and the airfoil region for maximum aerodynamic efficiency - while the transition region smoothly connects them.

Inventive Principle:
Principle #1Segmentation

4Power

If the blade focuses optimization on the airfoil region, then lift generation is improved, but overall aerodynamic performance deteriorates due to unoptimized root and transition regions

Engineering Contradiction:
Improvelift generationVSAvoidoverall aerodynamic performance
Core Design Contradiction:
PowerVSProductivity

Solution Approach 1:

The patent applies universality by designing the blade so that all regions - root, transition, and airfoil - contribute to overall aerodynamic performance. The root region is optimized to minimize drag and promote smooth airflow attachment, the transition region is designed to smoothly guide the airflow while maintaining energy production, and the airfoil region generates lift. This multi-functional optimization ensures that the entire blade works together efficiently, with each region contributing to both its primary function and overall aerodynamic performance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution enhances the aerodynamic performance by increasing lift and energy yield by 1-2% annually compared to conventional blades, while also simplifying the mounting process and reducing structural loads.

Implementation Method 1

the flow guiding device creates an air pocket in front of the front surface, which increases the local pressure in front of the flow guiding device, and which guides the airflow around the flow guiding device

Methodology Applied
Scientific EffectAir pocket formation:

Implementation Method 2

an air pocket is formed in front of the front surface, which increases the pressure in front of the flow guiding device

Methodology Applied
Scientific EffectPressure increase: Pressure Increase

Implementation Method 3

the pressure is increased both in front and behind of the flow guiding device, which in turn increases the lift significantly on this section of the blade

Methodology Applied
Scientific EffectLift generation:

Implementation Method 4

Downstream of the flow guiding device, i.e. typically between the flow guiding device and the trailing edge of the blade, a separation of the airflow occurs

Methodology Applied
Scientific EffectAirflow separation: Flow Separation

Data Source

PatentEP2360374B1Wind turbine blade having a forwardly oriented flow guiding device
Publication Date: 2019.05.08 LM WIND POWER AS
  • EP2360374B1 patent drawingFigure 1
  • EP2360374B1 patent drawingFigure 2
  • EP2360374B1 patent drawingFigure 3~4

AI summary

A wind turbine blade with a flow guiding device attached to a profiled contour on a pressure side of the blade is described. The flow guiding device has a front surface facing toward an oncoming airflow and comprises at least a first portion, which is angled towards the oncoming airflow and a leading edge of the wind turbine blade.