Evaporative Cooling for Electric Rotating Machine Heat Management
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Solution Overview
Problem
Electrical rotating machines face limitations in power density due to inefficient cooling methods, particularly with air, which fail to effectively manage heat transfer and volumetric constraints, leading to increased component temperatures and manufacturing costs.
Innovation Solution
The implementation of evaporative cooling with mixed condensation using a coolant that undergoes phase change and subsequent condensation in proximity to heat sources, utilizing low-viscosity silicone oils and atomization devices to enhance heat transfer coefficients and reduce system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If air cooling is used in electrical rotating machines, then the cooling system is simple, but the heat transfer efficiency is insufficient leading to increased component temperatures
Solution Approach 1:
The patent employs evaporative cooling where liquid coolant absorbs heat from stator and rotor components by evaporating, then the vapor condenses in a heat exchanger. This phase transition process significantly enhances heat transfer efficiency compared to conventional air cooling, effectively reducing component temperatures while maintaining system compactness
Solution Approach 2:
The patent introduces a closed-loop coolant circulation system using liquid coolant (such as water or dielectric fluid) that flows through channels in the stator and rotor, evaporates to absorb heat, and returns via condensation. This hydraulic approach replaces simple air cooling with a controlled fluid circulation system that achieves superior thermal management
2Productivity
If conventional cooling methods are used, then the system structure is simple, but the volumetric power density is limited due to insufficient heat dissipation capacity
Solution Approach 1:
By utilizing the latent heat of vaporization during coolant evaporation and condensation, the system achieves high heat dissipation capacity in a compact volume. The phase change process allows for efficient heat removal that directly supports higher power density without proportionally increasing cooling system volume
Solution Approach 2:
The cooling system is integrated within the machine structure by embedding coolant channels within the stator and rotor components themselves. The evaporative cooling zones are positioned adjacent to heat-generating components, and the condensation chamber is nested within the machine housing, creating a compact nested arrangement that maximizes volumetric power density
3Temperature
If evaporative cooling is implemented without proper separation, then heat transfer efficiency increases, but coolant fluid enters the condensation chamber uncontrollably
Solution Approach 1:
The patent divides the cooling system into distinct functional zones: an evaporation zone where liquid coolant evaporates to absorb heat from components, a separation zone with a separator that prevents liquid carryover, and a condensation zone where vapor condenses in the heat exchanger. This segmentation ensures controlled phase transition while preventing liquid coolant from entering the condensation chamber
Solution Approach 2:
A separator is introduced as an intermediary component between the evaporation zone and condensation chamber. This separator acts as a barrier that allows vapor to pass through while blocking liquid coolant droplets, ensuring that only vapor reaches the condensation chamber and maintaining proper flow control
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 significantly increases heat transfer efficiency, reduces coolant volume flows, and minimizes the inhibiting effects of inert gases, achieving higher power density and lower operational costs by spatially separating evaporation and condensation processes within a closed circuit.
Implementation Method 1
means for evaporative cooling of at least a part of the stator (2) and/or the rotor (3) with an evaporative coolant (V)
Implementation Method 2
means for mixed condensation of the evaporated evaporative coolant (V) with a liquid condensing coolant (K) in a mixed condensation chamber (17)
Data Source
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AI summary
The invention relates to an electric rotating machine (1) comprising a rotor (3) and a stator (2). In order to simply and efficiently cool the electric rotating machine (1) close to the ambient pressure, it is proposed that the electric rotating machine (1) comprises means for evaporation cooling at least one part of the stator (2) and/or the rotor (3) using the evaporation cooling means (V) and means for the mixed condensation of the vaporized evaporation cooling means (V) with liquid condensation cooling means (K).