Stator End-Turn Spray Cooling Manifold for Windage Loss Control
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Solution Overview
Problem
High power density electric generators face challenges in effectively cooling their end turns without incurring windage losses or requiring additional iron and copper, which makes traditional heat extraction methods ineffective at high power levels.
Innovation Solution
A manifold with integrated spray nozzles is used to direct atomized cooling oil directly onto the end turns of stator coils, increasing the heat transfer coefficient and providing full coverage for efficient heat extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If spray cooling technique is used to cool the generator, then heat extraction efficiency is improved, but windage losses increase due to oil contact with high-speed rotor components
Solution Approach 1:
The cooling system is segmented into two distinct zones: spray cooling is applied only to the stator end turns (non-rotating components), while conduction cooling is used for the rotor and stator back-iron. This segmentation allows spray cooling to be used without exposing rotating rotor components to oil, thereby maintaining high heat extraction efficiency while avoiding windage losses.
Solution Approach 2:
Different cooling methods are applied to different parts of the generator based on their specific thermal and operational characteristics. Spray cooling is locally applied to the stator end turns where high heat flux exists and rotating components are absent, while conduction cooling is used for rotating parts. This local quality approach optimizes cooling effectiveness while minimizing energy losses.
2Power
If traditional conduction cooling and spray cooling methods are used at megawatt class power levels, then cooling is provided, but additional iron and copper losses make these methods ineffective
Solution Approach 1:
The invention employs hydraulic spray cooling using oil as the cooling medium, delivered through precisely engineered nozzles that atomize the oil into fine droplets. This hydraulic approach provides superior heat extraction capability compared to traditional conduction cooling, enabling the system to handle megawatt class power levels while minimizing iron and copper losses through efficient thermal management.
3Weight of stationary object
If high efficiency generators are used to enable cooling with minimal weight and volume impact, then cooling capability is improved, but the generator must operate at high power density which increases heat generation
Solution Approach 1:
The invention changes the physical parameters of the cooling system by using spray cooling with atomized oil droplets instead of traditional liquid pools or conduction-only systems. This parameter change enables high heat flux removal at reduced weight and volume, allowing the generator to operate at high power density while maintaining effective cooling. The spray cooling parameters (droplet size, velocity, distribution) are optimized to maximize heat transfer efficiency.
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 enables continuous operation of high power density generators at rated power levels with improved cooling efficiency, reducing weight and size while minimizing losses.
Implementation Method 1
A manifold with integrated spray nozzles is used to direct atomized cooling oil directly onto the end turns of stator coils
Implementation Method 2
spray cooling technique provides very good heat extraction
Implementation Method 3
increasing the heat transfer coefficient and providing full coverage for efficient heat extraction
Data Source
AI summary
A manifold for cooling the end turns of stator coils of a generator is provided. The manifold includes a ring having a surface with a plurality of spray nozzles formed integral with the ring and extending from the surface. Each spray nozzle of the plurality of spray nozzles includes a channel having a diameter, and a surface having a selected width and an angle, wherein the channel and the surface are configured to spray oil on first end turns of the stator coils.