Wind Turbine Blade Radial Induction Profile for Thrust Control
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Solution Overview
Problem
Offshore wind turbines are designed with a focus on aerodynamic efficiency, which is suboptimal for reducing the high costs associated with the thrust overturning moment, leading to increased levelized cost of energy (LCOE) due to excessive support structure requirements.
Innovation Solution
The design of wind turbine blades with a radially varying loading profile, where the inboard region has an induction factor of 0.1-0.25 and the outboard region has an induction factor of 0.15-0.33, optimizing energy capture while controlling thrust overturning moment, thereby reducing support structure costs and increasing annual energy production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wind turbine blades are designed with conventional aerodynamic optimization (axial induction of 1/3), then energy capture is maximized, but thrust overturning moment increases leading to higher support structure costs
Solution Approach 1:
The patent applies different induction factors to different radial regions of the blade. The inboard region (inner 40% of blade span) uses an induction factor of 1/3 for optimal energy capture, while the outboard region (outer 60% of blade span) uses a reduced induction factor of 1/6. This localized differentiation allows the blade to capture energy effectively near the hub while reducing thrust forces at the tip where they contribute most to overturning moment.
Solution Approach 2:
The blade is segmented into two distinct regions with different aerodynamic characteristics. The inboard region and outboard region are treated as separate zones with independently optimized induction factors. This segmentation enables the design to balance competing objectives by allowing different parts of the blade to serve different functions - energy capture in the inboard region and thrust reduction in the outboard region.
2Productivity
If blade length is increased to capture more energy, then annual energy production increases, but thrust overturning moment increases requiring more expensive foundations
Solution Approach 1:
By applying reduced induction factor (1/6) specifically to the outboard region of longer blades, the patent enables extended blade lengths to capture more energy from wider wind resource without proportionally increasing thrust forces. The localized aerodynamic optimization in the outboard region ensures that additional blade length contributes to energy capture while maintaining controlled thrust levels.
Solution Approach 2:
The patent changes the induction factor parameter from the conventional uniform 1/3 across the entire blade to a radially varying distribution (1/3 inboard, 1/6 outboard). This parameter change fundamentally alters the relationship between blade length, energy capture, and thrust generation, enabling longer blades to be deployed without linearly increasing foundation requirements.
3Ease of manufacture
If conventional blade design is used for offshore applications, then manufacturing and installation are straightforward, but levelized cost of energy is high due to expensive support structures
Solution Approach 1:
The patent implements a locally differentiated induction factor distribution that reduces thrust overturning moment without requiring fundamental changes to manufacturing processes. The inboard region maintains conventional 1/3 induction for ease of manufacture, while the outboard region uses reduced 1/6 induction to lower loads on support structures, thereby reducing overall system cost.
Solution Approach 2:
By modifying only the induction factor parameter in the outboard region while keeping the inboard region conventional, the patent achieves lower levelized cost of energy through reduced foundation requirements without introducing complex manufacturing changes. This parameter-based approach maintains manufacturing simplicity while improving economic performance.
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 approach results in a higher ratio of annual energy production per thrust overturning moment, reducing the system-levelized cost of energy and allowing for longer blades to increase energy capture without exceeding thrust limits, thereby lowering foundation costs.
Implementation Method 1
The blade includes an inboard region and an outboard region. The inboard region has an average induction factor of between 0.1 and 0.25, and the outboard region has an average induction factor between 0.15 and 0.33
Data Source
AI summary
A wind rotor is disclosed that produces energy optimally for a given thrust overturning moment. By designing rotors with suboptimal aerodynamic efficiency, they can have optimal thrust performance, which will reduce the substructure cost and/or enable greater energy capture for a given substructure.