Wind Turbine Rotor Blade Extension Portion Framework
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Solution Overview
Problem
Wind turbine rotor blades face structural challenges due to increased loading when attempting to enhance aerodynamic performance by increasing the chord-wise dimension, particularly in the root region, which can lead to buckling and material strain.
Innovation Solution
A rotor blade design featuring a separate extension portion with a permanent framework and lightweight skin, which can be appended to the trailing edge to increase chord length without significantly increasing weight, shifting structural loads closer to the neutral axis and minimizing material strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the chord-wise dimension of the blade is increased in the root region to enhance aerodynamic performance, then the surface area presented to the wind is increased, but structural loading and material strain are significantly increased
Solution Approach 1:
The blade is divided into a main blade portion and a separate extension portion that can be appended to the trailing edge. This segmentation allows the chord-wise dimension to be increased at the root region without increasing the weight of the entire blade, as only the extension portion adds to the chord length. The extension portion is connected via connection members that allow relative movement, separating the structural function of the main blade from the aerodynamic function of the extended surface.
Solution Approach 2:
The extension portion utilizes a flexible skin or membrane surface that is tensioned over a framework structure. This flexible surface configuration allows the extension portion to be lightweight while maintaining structural integrity and aerodynamic shape. The flexible nature of the skin reduces the weight compared to a rigid structure, enabling increased surface area without proportionally increasing structural loading.
2Productivity
If the chord-wise dimension is increased to compensate for slower tangential velocity in the root region, then aerodynamic performance is improved, but the trailing edge describes a convex profile that increases fluctuating strains and causes buckling
Solution Approach 1:
By separating the blade into a main portion and an extension portion, the convex profile at the trailing edge is eliminated. The extension portion is appended to the straight trailing edge of the main blade, creating a straighter overall trailing edge profile. This segmentation allows the aerodynamic benefits of increased chord length without the structural penalties of a convex profile.
Solution Approach 2:
The connection members between the extension portion and main blade are designed to allow relative movement between the two portions. This dynamic connection enables the extension portion to move independently to some extent, reducing the transmission of fluctuating strains and buckling forces from the main blade to the extension portion, thereby improving reliability under cyclic loading.
3Strength
If a rigid structure is used to increase chord length, then structural strength is improved, but weight increases significantly
Solution Approach 1:
The extension portion employs a flexible skin or membrane that is tensioned over a lightweight framework. This flexible surface configuration provides the necessary structural strength to withstand aerodynamic loads while minimizing weight. The flexible skin acts as a tensile element that distributes loads throughout the extension portion, eliminating the need for heavy rigid structures.
Solution Approach 2:
The extension portion utilizes a composite structure combining a lightweight framework with a flexible skin or membrane material. This composite construction provides high strength-to-weight ratio, achieving the necessary structural strength for load bearing while keeping the weight minimal. The framework provides rigidity where needed, while the flexible skin provides tensile strength and aerodynamic surface.
4Ease of manufacture
If the blade is designed as a single integrated structure, then manufacturing is simplified, but transportation and maintenance become more difficult
Solution Approach 1:
The blade is segmented into a main blade portion and a separate extension portion that can be manufactured independently and then appended together. This segmentation allows each portion to be manufactured using optimized processes for its specific requirements, and enables easier transportation by reducing the size of individual components. The extension portion can be attached to the main blade at the root region, maintaining structural integrity while improving operational flexibility.
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 design reduces structural loading, enhances aerodynamic performance, and allows for easier transportation and maintenance by separating the blade and extension portions, while minimizing the risk of buckling and damage from extreme loads.
Implementation Method 1
transmit aerodynamic loads exerted on the skin, along the chord-wise members to a trailing portion of a rotor blade to which the extension portion is connected
Data Source
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AI summary
A wind turbine rotor blade extension portionconfigured to be connectable to a rotor bladeis provided. The extension portion comprises a permanent framework, having one or more chord-wise members and a substantially span-wise member. A membrane is located over the framework to thereby generate a streamlined surface. The extension portion is configured to transmit aerodynamic loads from the membrane, along the chord-wise members to a rotor blade to which the extension portion is connected, in use.