Flexible Trailing Edge Vortex Generators for Wind Turbine Blades
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Solution Overview
Problem
Wind turbine blades experience flow separation at trailing edge devices during bending, leading to increased drag and noise due to high angles of attack, which existing devices fail to prevent effectively.
Innovation Solution
Incorporating flexible members at the trailing edge of wind turbine blades that flex under airflow to deploy vortex generators, which are raised above the surface to prevent flow separation, using mechanisms like serrations or acoustic flaps, and are connected to actuators or sensors for dynamic deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If trailing edge devices are used to adjust flow, then lift is increased and drag is reduced, but flow separation occurs during bending due to high angles of attack
Solution Approach 1:
The trailing edge device is designed to be flexible rather than rigid, allowing it to dynamically adapt its shape during blade bending. The device comprises a flexible base portion and flexible projection elements that can bend and deform with the blade structure, maintaining optimal aerodynamic angles and preventing flow separation during dynamic operation.
Solution Approach 2:
The trailing edge device utilizes flexible materials and thin-walled structures that can bend and flex under aerodynamic loads. The flexible base portion and projection elements are constructed to allow controlled deformation, enabling the device to maintain attached flow conditions even when the blade experiences bending moments during operation.
2Strength
If trailing edge devices are rigid, then structural strength is maintained, but flow separation increases during blade bending
Solution Approach 1:
The trailing edge device employs flexible shells and thin-walled structures that can bend and flex under aerodynamic loads. The flexible base portion and projection elements are constructed to allow controlled deformation, enabling the device to maintain attached flow conditions even when the blade experiences bending moments during operation.
Solution Approach 2:
The device incorporates composite material structures combining rigid and flexible properties. The base portion may use composite laminates with varying fiber orientations to provide both structural strength and controlled flexibility, while projection elements use materials that balance stiffness for aerodynamic effectiveness with flexibility to prevent flow separation during blade deformation.
3Loss of energy
If flexible members are deployed to prevent flow separation, then drag is reduced, but device complexity increases
Solution Approach 1:
The trailing edge device is designed to be self-actuating, using the aerodynamic loads and blade bending itself to activate the flexible projections. No external actuators, sensors, or control systems are required - the device automatically adjusts its configuration in response to flow conditions and structural deformation, reducing complexity while maintaining drag reduction effectiveness.
Solution Approach 2:
The invention extracts and eliminates the complex actuation and control systems from the trailing edge device design. By relying on passive flexible structures that respond naturally to aerodynamic loads and blade bending, the design removes the need for motors, sensors, control electronics, and associated complexity, achieving drag reduction through simple flexible geometry alone.
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 deployment of vortex generators ensures attached flow over the trailing edge devices, reducing drag and noise by maintaining laminar flow and maximizing the effect of aerodynamic devices near the trailing edge, enhancing operational efficiency.
Implementation Method 1
One issue with such devices, however, is that the bending of such devices during operation of the wind turbine may result in flow separation is the region of the devices, due to the relatively high angle of attack in the region of the bent devices.
Implementation Method 2
the flexing of said at least one flexible member acts to deploy at least one aerodynamic device, preferably vortex generators, at the trailing edge of the wind turbine blade, to prevent flow separation over said at least one flexible member
Data Source
AI summary
A wind turbine blade is described, as well as a trailing edge plate for a wind turbine blade. A flexible flow modulation device, e.g. an acoustic flap or a plurality of serrations, is arranged at the trailing edge of a wind turbine blade, wherein the flexible device is coupled to at least one aerodynamic device, preferably vortex generators. As the flexible device is bent by action of flow over the wind turbine blade, the at least one aerodynamic device is deployed to provide for attached flow over the bent flexible device.