Rotor Jacket Longitudinal Channels Coolant Residence Time
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-speed electric motors experience ineffective heat transfer due to coolant being blown away from the rotor end ring, leading to insufficient cooling.
Innovation Solution
A rotor jacket with longitudinal channels and strategically placed inlets and outlets is integrated into the rotor, allowing coolant to flow through the channels, maximizing residence time and heat transfer by retaining the coolant closer to the inner radius, enhancing coolant balancing and spreading for improved winding cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If coolant is injected onto the end ring of the electric motor, then cooling is provided, but the coolant is blown away and heat transfer is ineffective
Solution Approach 1:
The cooling system is segmented into multiple functional components: a shaft jacket for coolant distribution, longitudinal channels in the rotor jacket for targeted cooling, and strategically positioned outlets. This segmentation allows the coolant to be delivered precisely to hot spots in the rotor and windings, preventing the blanket spraying approach that causes coolant to be blown away.
Solution Approach 2:
The rotor jacket acts as an intermediary component between the coolant supply system and the rotor components requiring cooling. It receives coolant from the shaft jacket and distributes it through longitudinal channels to the permanent magnets and rotor body, while the outlets positioned near the inner radius serve as intermediaries to retain coolant in the cooling path.
2Reliability
If outlets are positioned to allow coolant to exit freely, then coolant flow is simple, but coolant residence time is reduced and heat transfer is maximized less effectively
Solution Approach 1:
The outlets are positioned with specific local quality considerations - located near the inner radius of the rotor jacket rather than uniformly distributed. This localized positioning creates a specific flow pattern where coolant exits closer to the shaft, utilizing the centrifugal force and pressure gradient to maintain coolant in the cooling channels longer, thereby increasing residence time and heat transfer effectiveness.
3Temperature
If longitudinal channels are positioned closer to permanent magnets, then heat transfer to magnets is improved, but channel shape complexity increases
Solution Approach 1:
The longitudinal channels have a trapezoidal cross-section that is optimized for the dynamic cooling requirements. The wider top surface of the trapezoidal channel allows for better coolant distribution and heat transfer to the permanent magnets above, while the narrower bottom provides structural integration with the rotor jacket. This geometric optimization balances heat transfer effectiveness with manufacturability.
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 design effectively reduces rotor temperature by increasing coolant residence time and heat transfer, ensuring efficient cooling of high-speed electric motors.
Implementation Method 1
heat transfer between the coolant and the electric motor
Implementation Method 2
coolant flowing through the plurality of longitudinal channels
Data Source
AI summary
A permanent magnet electric motor includes a shaft extending along a longitudinal axis, wherein the shaft defines a shaft jacket extending along a first direction, a rotor mounted on the shaft, a stator disposed about the rotor. The rotor defines a plurality of longitudinal channels each with the shaft jacket. The longitudinal channels are part of a rotor jacket. The rotor jacket includes a plurality of inlets fluidly interconnecting the shaft jacket and the plurality of the longitudinal channels. The rotor jacket includes an inner edge and an outer edge opposite the inner edge. The rotor jacket includes a plurality of outlets each in fluid communication with the plurality of longitudinal channels. Each of the outlets is closer to the inner edge than to the outer edge of the rotor jacket.