Wind Turbine Generator Stator Cooling With Bidirectional Flow
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Solution Overview
Problem
As modern wind turbines generate higher output powers, leading to increased torque densities and elevated operating temperatures in the stator and rotor, existing cooling systems struggle to efficiently manage these temperatures, particularly in the stator windings and permanent magnets.
Innovation Solution
A liquid cooling system is implemented with at least two side ports at opposite axial ends and a central port at the axial center of the stator, allowing cooling liquid to flow bidirectionally through the stator, splitting into branches that cover all axial positions with opposite flow directions to enhance heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling liquid flows through the entire axial length of the stator in a single direction, then the cooling liquid covers all axial positions, but the temperature difference between the cooling liquid and stator decreases along the flow path, reducing cooling efficiency
Solution Approach 1:
The cooling liquid flow is segmented into multiple branches with different flow paths. Instead of a single continuous flow through the entire axial length, the cooling liquid is divided into separate flow channels that can be optimized independently, allowing each branch to maintain higher temperature differences for more effective heat transfer.
Solution Approach 2:
The conventional unidirectional flow through the entire axial length is inverted by introducing bidirectional flow paths. Cooling liquid can flow in opposite directions through different branches, allowing the cooler liquid to contact hotter stator regions and maintain higher temperature gradients throughout the cooling process.
2Temperature
If the cooling liquid flows through the entire axial length of the stator, then all axial parts are cooled, but the time span and path length increase, reducing the temperature difference and cooling efficiency
Solution Approach 1:
The axial length of the stator is segmented into different cooling zones served by separate flow branches. Each branch covers specific axial regions, reducing the path length and residence time in each segment while ensuring complete coverage of all axial positions through the combined action of multiple branches.
Solution Approach 2:
The cooling approach transitions from a single-dimensional axial flow to a multi-dimensional flow pattern with multiple branches. This allows cooling liquid to access different axial regions through parallel paths, effectively reducing the maximum path length while maintaining comprehensive coverage.
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 configuration reduces the time and path length of cooling fluid through the stator, increasing the temperature difference and improving cooling efficiency by enhancing heat transfer from the stator to the cooling liquid.
Implementation Method 1
the energy or heat transfer from the stator to the cooling liquid is larger
Implementation Method 2
heat transfer from the stator to the cooling liquid
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Electric generator for a wind turbine (1), comprising a stator (10) and a rotor (11) having two axial ends opposed to each other, wherein a liquid cooling arrangement (24) for cooling the stator (10) by guiding a cooling liquid (25) through the stator (10) is provided, wherein at least two side ports (28) which are arranged at the two opposite axial ends of the stator (10) and at least one central port (29) which is arranged at an axial center of the stator (10) are provided, wherein the liquid cooling arrangement (24) comprises at least one fluid channel (30, 43, 44) for leading the cooling liquid (25) bidirectionally through the stator (10) such that the cooling liquid (25) either enters the stator (10) through the side ports (28) and leaves the stator (10) through the central port (29) or enters the stator (10) through the central port (29) and leaves the stator (10) through the side ports (28).