Wind Turbine Moulding System Heat Redistribution
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Solution Overview
Problem
Conventional wind turbine blade manufacturing methods result in imperfections and cracks due to excessive heat generation during the curing process, leading to reduced strength and increased production costs, particularly in larger blades where stress and thermal expansion mismatches cause inhomogeneous shrinkage and residual stress.
Innovation Solution
A moulding system with an outer heat redistribution system, comprising channels and coolant fluid circulation, and optionally an inner heat redistribution system, to manage and redistribute heat generated during curing, ensuring a more uniform temperature distribution and reducing peak temperatures in high-stress areas like the spar cap, thereby minimizing shrinkage and residual stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the laminate thickness is increased to reduce stress on the blades, then the strength is improved, but the reaction heat from the curing process increases causing more severe thermal problems and imperfections
Solution Approach 1:
The mould body is divided into multiple zones with independently controllable heating and cooling elements. The mould includes heating elements positioned against the windward side surface and cooling elements positioned against the leeward side surface, allowing separate temperature control of different blade regions. This segmentation enables the thick spar cap areas to be cooled while other areas maintain optimal curing temperatures.
Solution Approach 2:
Different regions of the mould are equipped with different thermal management characteristics. The cooling elements are specifically positioned to address the high heat generation in thick laminate areas (spar cap), while heating elements are positioned in areas that require higher temperatures for proper curing. This local differentiation allows optimized temperature control for each zone's specific requirements.
2Ease of manufacture
If conventional curing methods are used, then the manufacturing process is simple, but the blades exhibit imperfections and cracks leading to decomposition and severe failures
Solution Approach 1:
The moulding system incorporates temperature sensors positioned at multiple locations within the mould cavity to monitor the actual temperature during curing. These sensors provide real-time feedback to a control system that automatically adjusts the heating and cooling element operation to maintain the desired temperature profile. This closed-loop control ensures consistent, defect-free curing while maintaining operational simplicity.
3Strength
If the curing time is prolonged at lower temperatures to reach better material properties, then the material quality is improved, but the production time increases causing higher costs
Solution Approach 1:
The curing process uses periodic or staged temperature profiles rather than continuous constant temperature. The control system activates heating and cooling elements in sequences, creating controlled temperature cycles that promote thorough curing and material property development while maintaining the overall process duration efficient. This periodic thermal action ensures complete curing without requiring excessively long continuous exposure.
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 system effectively reduces crack initialization and improves the homogeneity of the curing reaction, enhancing the fatigue properties and geometric stability of the rotor blades by maintaining a stable temperature and reducing unwanted geometric changes, resulting in higher-quality, stronger wind turbine blades with fewer imperfections.
Implementation Method 1
cooling elements (e.g., cooling channels) positioned at least partially in contact with the laminate stack... adapted to remove reaction heat generated during cross-linking of the resin
Implementation Method 2
cooling fluid circulation, and optionally an inner heat redistribution system, to manage and redistribute heat generated during curing
Implementation Method 3
heating elements positioned against the windward side surface... adapted to redistribute heat generated during manufacturing the rotor blade
Implementation Method 4
reaction heat generated during the curing process... cross-linking of the resin... extensive heat is generated during a curing reaction or cross-linking reaction
Data Source
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AI summary
It is described a moulding system (400, 500, 600, 700) for manufacturing a rotor blade (100) of a wind turbine, the system comprising: at least one outer mould (423, 425) having a outer mould body (427, 431) with a moulding surface (429, 433) complementary to an intended outer surface portion (101, 103) of the rotor blade; an outer heat redistribution system (435, 437, 661) within the outer mould body (427, 431) for redistributing heat from a spar cap area (113, 115) of the blade towards a leading edge (105) and/or a trailing edge (107) of the blade (100).