Wind Turbine Slat Tip Vortex Modification Appendage
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Solution Overview
Problem
The inboard portion of wind turbine blades is aerodynamically inefficient due to high variations in angle of attack, structural limitations, and non-optimal airfoil shapes, leading to reduced lift and torque production, which affects wind energy conversion efficiency.
Innovation Solution
The implementation of a flatback slat with a tip vortex modification appendage, such as a winglet or splitter plate, positioned to reduce the adverse effects of tip vortices and improve aerodynamic performance by altering the flow characteristics over the blade span, allowing for more consistent air inflow angles and increased lift across a broader range of operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the inboard portion of the blade is made thick to support structural loads, then the blade root strength is improved, but the aerodynamic efficiency deteriorates due to non-optimal airfoil shapes and high angle of attack
Solution Approach 1:
The blade is divided into inboard and outboard portions with different structural characteristics. The inboard portion maintains thickness for structural strength while the outboard portion has optimized airfoil shapes for aerodynamic efficiency. This segmentation allows each region to be optimized for its primary function without compromising the other.
Solution Approach 2:
Different airfoil shapes and thickness distributions are applied to different radial positions along the blade. The inboard portion uses thick profiles suitable for structural loads, while the outboard portion uses thinner, more aerodynamically efficient profiles. This local optimization resolves the contradiction between structural requirements and aerodynamic performance.
2Ease of manufacture
If the chord angle or twist angle is kept constant for manufacturing simplicity, then the manufacturing ease is improved, but the aerodynamic performance deteriorates due to excessive angle of attack variations
Solution Approach 1:
Instead of implementing a complex variable twist angle along the entire blade length, the patent applies a partial twist optimization in the outboard region where aerodynamic performance is most critical. The inboard region maintains a constant chord angle for manufacturing simplicity, achieving a balance between ease of manufacture and aerodynamic performance.
3Productivity
If flow altering devices such as slats are added to improve aerodynamic performance, then the lift production is improved, but the device complexity increases
Solution Approach 1:
The slat device is designed to perform multiple functions: it delays flow separation at high angles of attack, increases lift production, and reduces tip vortex effects. By integrating these functions into a single aerodynamic element, the patent improves lift production without proportionally increasing device complexity.
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 solution enhances the aerodynamic efficiency of wind turbine blades by reducing tip vortex impact, improving lift production, and delaying flow separation, thereby increasing torque and overall power output.
Implementation Method 1
tip vortex modification appendage, such as a winglet or splitter plate, positioned to reduce the adverse effects of tip vortices
Implementation Method 2
delaying flow separation
Data Source
AI summary
A slat (30) extending along an inboard portion of a wind turbine main blade element (22). The slat may have an end vortex modification appendage, such as winglet (34), endplate (64), raked wingtip (70), or down turned wingtip (72), and may be located behind a line defined perpendicular to a mean camber line of the main blade element at a leading edge of the main blade element. At least the leading edge (42S) of the slat may be disposed within a zone (48) of airflow that generally parallels the suction side (40) of the main blade element. The slat may have a flatback trailing edge (44F). Vortex generators (60) may be attached to the slat. Slats may be retrofitted to a wind turbine rotor (20) by attaching them to the spar caps (56) of the blades or to the hub (26) of the rotor.