Morphing Segmented Wind Turbine Blade for Load Reduction
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Solution Overview
Problem
Large wind turbines face challenges with blade weight, high gravity loads, and rigid rotor/tower systems that lead to increased costs, noise, and environmental impacts, particularly at extreme scales, where scaling up efficiency and reducing costs while managing weight and flexibility is crucial.
Innovation Solution
The morphing segmented wind turbine concept, employing 'twist morphing' and 'downwind morphing' designs, uses segmented blades connected by screw sockets and tension cables, allowing for adaptive geometry and reduced blade weight by aligning loads with wind forces, which reduces structural stresses and enables larger downstream deflections, thus minimizing blade mass and system weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If wind turbine scale is increased to improve energy capture, then power generation capacity increases, but blade weight increases proportionally to D^2.35
Solution Approach 1:
The blade is divided into multiple segments that can move independently relative to each other. This segmentation allows the blade to flex and adapt to wind loads without requiring the entire blade structure to be massively stiff, thereby reducing overall blade weight while maintaining structural integrity at extreme scales.
Solution Approach 2:
The blade incorporates dynamic morphing capabilities where segments can change their relative positions and orientations in response to varying wind conditions. This dynamic adaptation allows the blade to optimize its aerodynamic performance across different operating conditions without requiring excessive structural reinforcement.
2Reliability
If blade stiffness is increased to prevent rotor-blade tower strikes in upwind configurations, then reliability improves, but high frequency fatigue loads increase
Solution Approach 1:
The blade uses dynamic segmental movement to actively manage its position and orientation, allowing it to flexibly respond to turbulent wind conditions without requiring excessive static stiffness. This dynamic behavior reduces impulsive loading and fatigue while maintaining reliability.
Solution Approach 2:
The blade's effective stiffness parameters are dynamically changed through segmental movement and morphing, allowing the structure to adapt its mechanical properties in real-time to match operating conditions, thereby reducing fatigue loads while maintaining reliability.
3Weight of moving object
If blade weight is reduced to lower system costs, then manufacturing and installation costs decrease, but structural strength may be compromised
Solution Approach 1:
The segmented blade structure distributes structural loads across multiple independent segments and their interconnections, allowing each segment to be optimized for minimal weight while maintaining overall structural strength through the collective system.
Solution Approach 2:
The blade utilizes composite material construction for the segments and their connections, providing high strength-to-weight ratio materials that maintain structural integrity while minimizing overall blade weight for cost reduction.
4Power
If rotor diameter is increased to capture more wind energy, then power generation increases, but manufacturing and shipping constraints are exacerbated
Solution Approach 1:
The blade is divided into multiple segments that can be manufactured separately in smaller, more manageable sizes and then assembled on-site. This segmentation overcomes manufacturing and shipping constraints while enabling the construction of extremely large rotor diameters for maximum energy capture.
Solution Approach 2:
The blade design incorporates out-of-plane bending capabilities and three-dimensional morphing that allow the structure to achieve its functional form through assembly and deployment rather than requiring the entire structure to be manufactured as a single monolithic piece.
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 allows for higher lift coefficients, reduced blade chord length, and lower overall system weight, enhancing energy capture while reducing manufacturing and installation complexities, and mitigating environmental impacts by minimizing noise and visual impacts.
Implementation Method 1
At high rotor rpm, the cable tension can be designed such that centrifugal forces drive the blade segments outward so as to unwind/feather the rotor and prevent over-speed
Implementation Method 2
the airfoils of the blade segments can be designed with a center of pressure downstream of the socket axis. This will cause an aerodynamic moment at high wind speeds which will serve to unwind the blade segments to prevent torque spikes and blade stall
Implementation Method 3
The twist morphing pertaining to an embodiment of the present invention may be accomplished by using segmented blades connected by screw sockets and a tension cable system
Data Source
AI summary
A downwind morphing rotor that exhibits bending loads that will be reduced by aligning the rotor blades with the composite forces. This reduces the net loads on the blades which therefore allow for a reduced blade mass for a given maximum stress. The downwind morphing varies the amount of downstream deflection as a function of wind speed, where the rotor blades are generally fully-aligned to non-azimuthal forces for wind speeds between rated and cut-out conditions, while only the outer segments of the blades are generally aligned between cut-in and rated wind speeds. This alignment for large (MW-scale) rated turbines results in much larger downstream deflections of the blades at high wind speeds as compared to that of a conventional rigid single-piece upwind turbine blade.