Wind Turbine Blades With Connecting Members for Load Relief
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Solution Overview
Problem
Existing wind turbine blades face challenges with increased loads and stresses due to larger sizes, leading to manufacturing difficulties, weight, cost, and aerodynamic performance issues, particularly at the inboard end where additional material or thickness is required for structural support.
Innovation Solution
The wind turbine design incorporates blade connecting members between neighboring blades, maintaining a substantially constant thickness or relative thickness in an inboard portion to distribute loads, allowing for aerodynamically optimized blades with reduced structural requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If more material is used near the inboard end of the blade, then the strength and rigidity of the blade root is improved, but the weight and cost of the blade increase
Solution Approach 1:
The blade is designed with non-uniform thickness distribution where the inboard portion has substantially constant or minimized thickness, while the outboard portion has increased thickness. This local quality variation allows the blade to achieve adequate strength at the root through optimized structural design rather than excessive material usage, reducing overall weight while maintaining necessary strength characteristics.
2Strength
If the diameter of the blade root is increased, then the strength and rigidity of the blade root is improved, but the difficulty of manufacture and transport increases
Solution Approach 1:
The blade root is designed with optimized dimensional characteristics that provide adequate strength and rigidity without excessive size. The inboard portion maintains substantially constant or minimized thickness, allowing the blade to achieve necessary structural performance through intelligent design rather than simply increasing root diameter, thereby facilitating easier manufacture and transport.
3Strength
If the thickness of the blade near the inboard end is increased, then the strength and rigidity of the blade root is improved, but the aerodynamic performance of the blade deteriorates
Solution Approach 1:
The blade employs variable thickness distribution where the inboard portion has substantially constant or minimized thickness to maintain aerodynamic efficiency, while the outboard portion has increased thickness to provide necessary structural strength. This local quality optimization ensures that the blade achieves adequate root strength without compromising aerodynamic performance through excessive thickness in the inboard region.
Solution Approach 2:
The blade is segmented into distinct functional zones: an inboard portion with optimized aerodynamic characteristics (substantially constant or minimized thickness) and an outboard portion with enhanced structural properties (increased thickness). This segmentation allows each region to be optimized for its primary function, resolving the contradiction between strength and aerodynamic performance.
4Productivity
If larger wind turbine blades are used, then the swept area and energy capture capability are improved, but the loads and stresses on the blade increase
Solution Approach 1:
The blade is designed with non-uniform thickness distribution where the inboard portion has substantially constant or minimized thickness, while the outboard portion has increased thickness. This local quality variation allows larger blades to capture more energy from the wind while the optimized thickness distribution manages the increased loads and stresses through strategic material placement rather than uniform thickening.
Solution Approach 2:
The blade is segmented into functional zones with different thickness characteristics: the inboard portion maintains aerodynamic efficiency with constant or minimized thickness, while the outboard portion provides structural strength with increased thickness. This segmentation enables larger blade designs that can handle the increased loads associated with greater swept area.
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 enhances aerodynamic performance while maintaining structural integrity, enabling longer blades that capture more energy without the drawbacks of traditional designs, potentially reducing weight and material usage.
Implementation Method 1
As such, a proportion of the loads experienced by the blade in use may be transferred to a plurality of blade connecting members, thereby reducing the load in each member.
Implementation Method 2
Each blade comprises a windward side and a leeward side which meet at a leading edge and a trailing edge to define an airfoil profile.
Data Source
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AI summary
In a first aspect of the present invention there is provided a wind turbine comprising a tower, a nacelle mounted on the tower, and a rotor mounted to the nacelle. The rotor comprises a hub and at least three pitchable wind turbine blades connected to the hub via respective pitch mechanisms. Each blade extends from a blade root defining a radial position r=0 to a blade tip defining a radial position r=R. Each blade comprises a windward side and a leeward side which meet at a leading edge and a trailing edge to define an airfoil profile. A chord is the distance between the leading and trailing edges, and a relative thickness is the ratio of thickness to chord. The airfoil profile has a thickness being the greatest distance between the windward and leeward sides orthogonal to the chord. Each blade comprises a connection point located at a first radial position (r1) between the blade root and the blade tip. The wind turbine further comprises one or more blade connecting members connected between the connection point and a corresponding connection point on a neighbouring blade. The thickness and/or the relative thickness of each blade is substantially constant or has a local minimum within an inboard portion of the blade between the blade root and the connection point.