Wind Turbine Blade Bulkhead Frame for Ovalization
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Solution Overview
Problem
Wind turbine blades experience ovalization due to aerodynamic forces, leading to increased stresses in the glue line and potential cracks, and the installation of de-icing systems becomes complicated due to the weight and size of required components.
Innovation Solution
A bulkhead unit with a frame structure that provides support and mounts additional components, allowing pre-assembly and reducing the need for additional reinforcing elements or increased thickness, while also facilitating the installation of de-icing systems and other components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If extra layers of core material or fibre material are added to the sandwich laminate to solve ovalisation, then the structural strength is improved, but the total weight and costs increase
Solution Approach 1:
The bulkhead unit is pre-assembled with the frame structure and additional components (heater units, blower units, cables) before installation in the wind turbine blade. This preliminary assembly allows for optimized weight distribution and eliminates the need for excessive reinforcing material in the blade structure itself.
Solution Approach 2:
The frame structure acts as an intermediary element between the bulkhead element and the blade shell. It provides the necessary structural support and mounting functionality without requiring additional core or fibre layers in the sandwich laminate, thus avoiding weight increase.
2Reliability
If flexible flanges or adjustable collars are used to attach the bulkhead to the blade shell to solve glue line stresses, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The frame structure is pre-assembled with the bulkhead element before installation. This preliminary assembly ensures proper alignment and distribution of stresses, allowing the use of simpler attachment mechanisms to the blade shell while maintaining reliability.
Solution Approach 2:
The frame structure is designed to inherently distribute and accommodate the ovalisation-induced stresses through its rigid geometry and attachment points, eliminating the need for additional flexible or adjustable components. The structure serves its own stress-accommodation function.
3Reliability
If large and heavy heater and blower units are installed inside the hub or at the blade root for de-icing, then the de-icing effectiveness is improved, but the installation complexity and time increase
Solution Approach 1:
The heater units, blower units, and associated components are pre-assembled on the frame structure with the bulkhead element before installation in the wind turbine blade. This preliminary assembly significantly reduces installation time and complexity while maintaining de-icing effectiveness.
Solution Approach 2:
The de-icing system components (heater units, blower units, cables) are merged with the bulkhead unit assembly, forming an integrated pre-assembled unit. This combination allows for simultaneous installation of multiple components as a single unit, improving productivity.
4Ease of manufacture
If the bulkhead unit is designed as a pre-assembled unit with frame structure, then the ease of manufacture is improved, but the lifting and installation requirements become more demanding
Solution Approach 1:
The bulkhead unit is segmented into the bulkhead element, frame structure, and additional components that can be pre-assembled together. This segmentation allows for modular manufacturing and controlled assembly, making the unit manageable despite its size and weight.
Solution Approach 2:
The frame structure serves as an intermediary that provides attachment points for lifting devices. This intermediary structure distributes the lifting forces across multiple points on the pre-assembled unit, making handling feasible despite the combined weight of all components.
Data Source
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AI summary
This invention relates to a bulkhead unit, a wind turbine blade comprising the bulkhead unit, a lifting device and methods of assembling and installing the bulkhead unit in the wind turbine blade. The bulkhead unit comprises a bulkhead element substantially extending in a radial direction and a frame structure attached to the bulkhead element. The frame structure provides support for the bulkhead element and additional components mounted to the frame structure. The frame structure comprises a plurality of frame elements which are interconnected to form a number of areas that are aligned with corresponding openings in the bulkhead element. The lifting device is used to lift the bulkhead unit into position and fix the bulkhead unit relative to the blade shell.