Wind Turbine Generator Cooling With Inter-Element Radiation Absorbers
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Solution Overview
Problem
In electrical machines, such as generators in wind turbines, thermal radiation between active rotor and stator elements increases cooling requirements and can lead to element failure, limiting power output and service life due to elevated temperatures.
Innovation Solution
Incorporating radiation absorbers between adjacent active elements to absorb thermal radiation, reducing the temperature of these elements and enhancing cooling efficiency by using a cooling fluid that flows around the absorbers, thereby preventing heat transfer between elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If thermal radiation is emitted by active elements, then energy conversion occurs, but temperature of neighboring active elements increases
Solution Approach 1:
A radiation absorber is introduced as an intermediary component between adjacent active elements. This absorber intercepts thermal radiation emitted by one active element before it reaches neighboring active elements, converting the radiant heat into thermal energy that can then be managed through conduction and convection pathways rather than direct radiative heating of sensitive components.
Solution Approach 2:
The harmful thermal radiation that would otherwise directly heat neighboring active elements is converted into beneficial thermal energy in the radiation absorber. This converted heat can then be efficiently removed through conduction to cooling structures and convection via cooling fluids, transforming a harmful radiative transfer into a manageable thermal conduction and convection process.
2Temperature
If cooling fluid is run through air gap, then heat is removed from active elements, but cooling system complexity increases
Solution Approach 1:
The radiation absorber is integrated with existing cooling structures such as stator or rotor cores, merging the radiation absorption function with the thermal management function. This combination eliminates the need for separate, complex cooling systems while effectively removing heat from both the active elements and the radiation absorber through the unified cooling fluid pathways.
Solution Approach 2:
The radiation absorber serves multiple functions simultaneously: it absorbs thermal radiation from active elements, conducts heat to cooling structures, and provides additional surface area for convection cooling. This multi-functionality reduces the need for separate dedicated cooling components, thereby simplifying the overall cooling system architecture.
3Loss of energy
If emissivity of active elements is high, then thermal radiation is effective, but temperature threshold failure risk increases
Solution Approach 1:
The radiation absorber acts as a mediator that intercepts thermal radiation before it reaches neighboring high-emissivity active elements. This prevents the compounding heating effect that would occur when radiated energy is absorbed by another high-emissivity surface, thereby reducing the risk of temperature threshold failure while preserving the beneficial thermal radiation characteristics of the active elements.
Solution Approach 2:
The air gap between active elements is segmented by introducing radiation absorbers at strategic locations. This segmentation breaks up the direct radiative pathways between active elements, allowing thermal radiation to be managed in discrete sections rather than as a continuous heating chain, thereby reducing peak temperatures and failure risk.
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 solution reduces the temperature of active elements, increases their service life, and enhances power output by minimizing the need for larger cooling systems and preventing temperature thresholds that could cause element failure.
Implementation Method 1
a radiation absorber arranged between a first and a second adjacent active rotor elements or between a first and a second adjacent active stator elements
Implementation Method 2
The cooling fluid contacts the active elements and takes heat from them away
Implementation Method 3
Thermal radiation emitted by the active elements, i.e. electromagnetic radiation of thermal nature, mainly in the infrared region of the electromagnetic spectrum
Data Source
AI summary
The present disclosure relates to electrical machines and methods for cooling active elements of electrical machines. More in particular, the present disclosure relates to generators and methods for cooling adjacent active rotor elements and/or adjacent active stator elements of a generator of a wind turbine, e.g. of a direct drive wind turbine. An electrical machine comprises a rotor including a plurality of active rotor elements, a stator including a plurality of active stator elements, and an air gap separating the active rotor elements and the active stator elements. The electrical machine further comprises a radiation absorber arranged between a first and a second adjacent active rotor elements or between a first and a second adjacent active stator elements.