Wind Turbine Rotor Blade Hub Profile With Thorn Trailing Edges

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Solution Overview

Problem

Large wind turbine rotor blades face challenges with high weight, complex transportation, and limited options for reducing weight while maintaining aerodynamic performance, particularly in the hub area where flow separation and turbulence issues arise due to blunt trailing edges.

Innovation Solution

Designing a rotor blade with a thickness profile in the hub area featuring a mandrel extension on the suction side and a second mandrel extension on the pressure side, which reduces profile depth and noise emission, and stabilizes vortex formation for improved lift and buoyancy behavior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the rotor blade diameter is increased to ensure constant electricity production in light wind regions, then the aerodynamic performance and electricity production are improved, but the rotor blade weight increases and transportation becomes more difficult

Engineering Contradiction:
Improveelectricity productionVSAvoidrotor blade weight
Core Design Contradiction:
ProductivityVSWeight of moving object

Solution Approach 1:

The patent applies different profile designs to different sections of the rotor blade. The hub area uses a thickness profile with mandrel extensions to reduce weight and improve flow conditions, while other areas maintain standard aerodynamic profiles. This local differentiation allows weight reduction in critical areas without compromising overall aerodynamic performance and electricity production capability.

Inventive Principle:
Principle #3Local quality

2Device complexity

If a blunt trailing edge is used in the hub area, then the structural simplicity is improved, but flow separation and turbulence occur reducing lift values

Engineering Contradiction:
Improveprofile structureVSAvoidaerodynamic performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The mandrel extensions act as intermediary structures that modify the flow field around the blunt trailing edge. By introducing these extensions, the patent creates controlled vortex formation that prevents harmful flow separation while maintaining the structural simplicity of a blunt trailing edge design. The mandrel extensions mediate between the simple geometry and the need for good aerodynamic performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potentially harmful flow separation at the blunt trailing edge into beneficial controlled vortices through the mandrel extensions. The blunt trailing edge that would normally cause turbulence and lift loss is transformed into a vortex-generating structure that actually improves flow attachment and maintains lift values in the hub area.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If the profile depth is reduced for easier transportation, then the weight and transport complexity are improved, but the aerodynamic performance and lift values deteriorate

Engineering Contradiction:
ImprovetransportationVSAvoidaerodynamic performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent compensates for reduced profile depth by adding mandrel extensions in the spanwise dimension (along the blade length). This dimensional transformation allows the blade to have reduced chord-wise depth for easier transportation while maintaining effective aerodynamic depth through the spanwise extensions, thereby preserving lift values and aerodynamic performance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Ease of manufacture

If a two-part rotor blade is realized to facilitate transport, then the transportation difficulty is reduced, but the stability is reduced due to the separation point

Engineering Contradiction:
ImprovetransportationVSAvoidblade stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent divides the rotor blade into two separate parts at the hub area, allowing each section to be transported independently. This segmentation facilitates transportation of large blades by breaking them into manageable sections that can be assembled on-site, directly addressing the transportation difficulty while maintaining structural integrity through proper connection design.

Inventive Principle:
Principle #1Segmentation

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 achieves a reduction in rotor blade weight and noise emission while maintaining lift values, allowing for more efficient transportation and improved aerodynamic performance by stabilizing vortex formation and increasing effective profile depth.

Implementation Method 1

stabilizes vortex formation for improved lift and buoyancy behavior

Methodology Applied
Scientific EffectVortex formation: Vortex Ring

Implementation Method 2

formation of a throat vortex in a throat between the first and second mandrel extensions

Methodology Applied
Scientific EffectThroat vortex: Vortex Ring

Implementation Method 3

flow separation at the trailing edge

Methodology Applied
Scientific EffectFlow separation: Flow Separation

Implementation Method 4

trailing edge turbulence

Methodology Applied
Scientific EffectTurbulence: Turbulence

Data Source

PatentEP3408533B1Rotor blade of a wind turbine and a wind turbine
Publication Date: 2021.03.17 WOBBEN PROPERTIES GMBH
  • EP3408533B1 patent drawingFigure 1
  • EP3408533B1 patent drawingFigure 2~5
  • EP3408533B1 patent drawingFigure 6

AI summary

The invention relates to a rotor blade (1) with a suction side and a pressure side for a wind turbine, having: a rotor blade root (4) of a hub area (I) for connecting the rotor blade (1) to a rotor hub and a rotor blade tip (5, 7) arranged on a side of a tip area (III) facing away from the rotor blade root (4). According to the invention, the rotor blade has a thickness profile at least partially in the hub area (I), said thickness profile having a thorn-shaped extension on its trailing edge, wherein the thickness profile has a first thorn-shaped extension on the trailing edge on the suction side at least partially in the hub area, and has a second thorn-shaped extension on the trailing edge on the pressure side, and the thickness profile has a flow stabilizer and/or a vortex generator on the suction and/or pressure side at least partially in the hub area.