Compliant Sensor for Wind Turbine Flow Separation
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Solution Overview
Problem
Existing methods for detecting flow separation on wind turbine blades are either intrusive, prone to damage, costly, or unreliable, particularly under extreme conditions, and fail to effectively suppress flow separation, leading to reduced efficiency and increased noise.
Innovation Solution
A sensor device comprising compliant elements that vibrate in the air current downstream of the trailing edge of the blade, equipped with sensors to measure these vibrations, which are used to detect flow separation and adjust the angle of attack to prevent it, utilizing a combination of sensors like accelerometers, strain gauges, and optical sensors to create a control signal for pitch angle and rotation speed adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors are oriented into the flow to detect flow separation, then detection capability is improved, but the sensors become susceptible to damage and clogging
Solution Approach 1:
The patent introduces compliant elements as intermediary structures that interact with the flow field without requiring sensors to be directly exposed to it. These elements translate flow separation effects into measurable vibrations, allowing indirect detection that protects the sensor from damage and clogging while maintaining detection precision
Solution Approach 2:
The invention replaces direct mechanical pressure sensing with a vibration-based detection system. Instead of using pressure sensors that must physically face the flow, the system uses compliant elements that vibrate in response to flow separation, with vibrations measured by non-intrusive sensors, substituting a fragile mechanical sensing approach with a more robust vibration measurement approach
2Measurement precision
If fiber-optic strain gauge measurements are embedded within the blade, then detection accuracy is improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent employs compliant elements that function as flexible sensing structures. These thin, flexible elements can be easily integrated into the blade structure without complex embedding processes, providing accurate flow separation detection while maintaining manufacturing simplicity and cost-effectiveness
Solution Approach 2:
Instead of using expensive fiber-optic sensors embedded in the blade, the invention uses simpler compliant elements that replicate the flow separation detection function. These elements capture the essential flow information through vibration patterns, providing a cost-effective alternative that achieves similar detection accuracy without the high manufacturing costs of embedded fiber-optic networks
3Measurement precision
If the compliant element is made highly compliant to vibrate in the air current, then detection sensitivity is improved, but the element becomes more susceptible to damage
Solution Approach 1:
The patent optimizes the compliance parameter of the sensing elements to achieve an optimal balance. By carefully selecting the compliance level, the elements become sufficiently sensitive to detect flow separation through vibration while maintaining enough structural integrity to withstand operational loads and avoid damage
Solution Approach 2:
The invention uses dynamic vibration characteristics rather than static compliance to detect flow separation. The compliant elements are designed to vibrate at specific frequencies when flow separation occurs, allowing detection through dynamic response rather than relying on extreme static compliance, thereby maintaining both sensitivity and structural strength
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 provides a reliable, non-intrusive method for detecting flow separation, allowing for real-time adjustments to prevent separation, reducing turbine loads, noise, and extending the lifespan of wind turbines by enabling operation at higher angles of attack, leading to more efficient and cost-effective energy production.
Implementation Method 1
a number of compliant elements with aerodynamic and/or structural properties designed to allow flow-induced vibrational motion in an air current downstream of the trailing edge
Implementation Method 2
a sensor-element designed to measure vibrations of the number of compliant elements
Data Source
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AI summary
A sensor device for measuring flow-separation on an aerodynamic element, including a number of compliant elements with aerodynamic and/or structural properties designed to allow flow-induced vibrational motion in an air current and a sensor-element designed to measure vibrations of the number of compliant elements is provided. Further provided is an aerodynamic element, e.g. a wind turbine blade or an airfoil, with such sensor device, a method for controlling the angle of attack of an aerodynamic element, a controlling device and a wind turbine.