Wind Turbine Rotor Blade Root Curtain for Aerodynamic Drag Reduction
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Solution Overview
Problem
Wind turbine rotor blades experience significant aerodynamic separation and energy losses due to their cylindrical root configuration, which hinders the effectiveness of add-on extensions and structures intended to improve aerodynamic performance.
Innovation Solution
A wind turbine rotor blade assembly featuring an edge extension with a contoured outer surface and a pliant, flexible curtain that extends from the terminal end to the root, accommodating connection to the rotor hub and pitch control movement, formed from materials like woven or non-woven fabrics or brush-like members to reduce airflow separation and drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If add-on extension structures are attached to improve aerodynamic profile, then aerodynamic performance is improved, but effectiveness is decreased due to cylindrical root configuration causing airflow separation
Solution Approach 1:
A flexible curtain made of pliant material is attached to the edge extension, extending from the terminal end toward the root. The curtain flexes to accommodate pitch control movement and connection to the rotor hub while maintaining aerodynamic benefits, effectively reducing airflow separation without compromising structural flexibility
Solution Approach 2:
The curtain is designed to be dynamically flexible, allowing it to move with the blade during pitch control operations. This dynamic adaptability enables the curtain to maintain its aerodynamic function while accommodating the operational movements of the rotor blade
2Ease of operation
If edge extensions are tapered or terminated spaced from the root, then connection to rotor hub is facilitated, but aerodynamic performance is decreased
Solution Approach 1:
The flexible curtain extends the aerodynamic benefit of the edge extension all the way to the root without requiring the rigid extension to be tapered or shortened. The curtain's flexibility allows it to conform to the root geometry and accommodate connection requirements while maintaining continuous aerodynamic coverage
Solution Approach 2:
The flexible curtain acts as an intermediary between the rigid edge extension and the rotor hub connection point. It bridges the gap, allowing the extension to maintain its full aerodynamic length while the curtain adapts to the connection requirements at the root
3Shape
If rigid extension structures are used to improve aerodynamic profile, then aerodynamic surface is improved, but adaptability to pitch control movement is reduced
Solution Approach 1:
The curtain is constructed from pliant, flexible material that can bend and flex to accommodate pitch control movement of the rotor blade. This flexibility allows the aerodynamic surface to adapt to operational movements while maintaining its aerodynamic function
Solution Approach 2:
The curtain transitions from a static rigid structure to a dynamic flexible structure that can adapt its shape and position in response to pitch control movements, maintaining aerodynamic effectiveness throughout the range of motion
Data Source
AI summary
A wind turbine rotor blade assembly includes a rotor blade having a pressure side, a suction side, a leading edge, and a trailing edge extending in a generally span-wise direction between a tip and a root. An edge extension is attached along either or both of the leading edge or trailing edge in a generally span-wise direction from adjacent the root towards the blade tip, with the edge extension having a contoured outer surface that defines a generally continuous aerodynamic surface. The edge extension has a terminal end that is spaced from root. A curtain is attached to the edge extension and extends in a span-wise direction from the terminal end t to the root. The curtain is formed from a pliant, flexible material that accommodates connection of the root to a rotor hub, as well as pitch movement of the rotor blade relative to the hub.