Wind Turbine Blade Joint Curing With Zoned Internal-External Heating
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Solution Overview
Problem
The existing methods for joining wind turbine blade sections face challenges in ensuring uniform and complete curing of the curable resin due to varying thicknesses of the fiber layup and thermal masses within the blade structure, leading to incomplete curing and non-optimal mechanical properties.
Innovation Solution
The method involves using an air heater device to supply heated air to the inner hollow spaces of the blade sections and an external heater with individually controlled heating zones to manage temperature variations, ensuring uniform curing of the curable resin by minimizing conductive heat loss and adjusting heating power based on local resin volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If external heating blankets are placed on the outer surface of the joining region, then the ambient temperature and surface temperature increase, but the thermal masses inside the blade sections cannot be heated to the desired temperature level due to conductive heat loss
Solution Approach 1:
Instead of heating from the outside surface, the patent heats from the inside hollow spaces of the blade sections. The air heater device supplies heated air into the inner hollow spaces, directly heating the thermal masses from the interior, thereby eliminating the problem of conductive heat loss through the thick blade structure.
Solution Approach 2:
The patent uses a pneumatic system (air heater device) to circulate heated air through the inner hollow spaces of the blade sections. This fluid-based heating method efficiently transfers thermal energy to the thermal masses and resin throughout the joining region, overcoming the limitations of surface heating.
2Temperature
If the fiber layup thickness varies in the joining region, then regions with thick fiber layup generate more heat during curing, but regions with thin fiber layup generate insufficient heat leading to incomplete curing
Solution Approach 1:
The patent applies local quality by providing heated air to different regions of the joining region according to their specific heating requirements. The air heater device can be positioned to direct heated air preferentially toward regions with thinner fiber layup that generate less exothermic heat, ensuring uniform temperature distribution and complete curing throughout the entire joining region.
Solution Approach 2:
The patent implements feedback control by monitoring the temperature distribution in the joining region and adjusting the heated air supply accordingly. Temperature sensors detect variations in temperature, and the air heater device responds by modifying the flow and temperature of heated air to maintain uniform curing conditions across regions with varying fiber layup thickness.
3Strength
If the blade sections are joined using a joining adapter with fiber layup and curable resin, then the mechanical strength of the joint is improved, but the varying thickness of fiber layup causes non-uniform heat generation during curing
Solution Approach 1:
The patent introduces heated air as an intermediary medium to transfer thermal energy uniformly throughout the joining region. The air heater device supplies heated air that acts as a mediator, distributing heat evenly across regions with varying fiber layup thickness, thereby ensuring uniform curing while maintaining the high mechanical strength provided by the joining adapter and curable resin.
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 achieves complete and uniform curing of the curable resin, resulting in a wind turbine blade joint with improved mechanical properties and reduced overheating or underheating issues.
Implementation Method 1
supplying a stream of heated air into the inner hollow spaces of the first and/or second blade sections
Implementation Method 2
minimizing conductive heat loss
Implementation Method 3
The epoxy cures under an exothermic reaction during which the molecules in the epoxy-hardener mixture react and generate heat
Implementation Method 4
external heater with individually controlled heating zones to manage temperature variations
Data Source
AI summary
Method for joining at least two sections of a wind turbine blade, use of an air heater device in a method for joining at least two sections of a wind turbine blade and external heater for use in a method for joining at least two sections of a wind turbine bladeThe method for joining at least two sections of a wind turbine blade involves providing an air heater device (3) and with the air heater device (3) supplying a stream of heated air into inner hollow spaces of first (11) and/or second blade sections (12) at least in a joining region (2) and/or placing an external heater (6) on an outer surface of the first (11) and/or second blade sections (12) at least in the joining region (2), wherein the external heater (6) comprises a multitude of heating zones (62-69), wherein a heating power in the heating zones (62-69) is individually controlled.The method according to the invention improves the curing of a curable resin used to join the blade sections (11,12).