Two-Phase Cooling Fins That Shift at Critical Heat Flux
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Solution Overview
Problem
Conventional two-phase cooling systems for electrical equipment in aircraft face critical heat flux issues, leading to potential drying out of the cooling fluid interface and excessive temperature increases, risking equipment damage, especially during high power operations.
Innovation Solution
A cooling device with thermally conductive fins that move between close and far positions based on temperature thresholds, using a two-phase cooling fluid and shape memory alloy to maintain effective heat exchange without reducing power, even during critical heat flux conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the operating temperature of power electronics is increased to meet space constraints, then the size of electrical equipment can be reduced, but heat losses increase significantly
Solution Approach 1:
The patent employs a two-phase cooling system where the cooling fluid transitions between liquid and vapor phases to efficiently remove heat from electrical equipment. The phase change occurs at the heated surface, absorbing large amounts of heat energy and enabling effective cooling at compact sizes without excessive heat losses
2Loss of energy
If a two-phase cooling system is used to reduce heat losses, then cooling efficiency improves, but the risk of wall drying out increases under critical heat flux conditions
Solution Approach 1:
The patent introduces movable fins that dynamically adjust their position based on temperature conditions. Under normal operation, fins are in a first position allowing optimal two-phase cooling. Under critical heat flux conditions, fins move to a second position to modify the cooling regime and prevent wall drying out, thereby maintaining reliability
Solution Approach 2:
The system incorporates temperature-based feedback control where the position of the fins is determined by the thermal state of the wall. When the wall temperature reaches a critical threshold, the feedback mechanism triggers fin movement to alter the cooling pattern and prevent dangerous temperature increases
3Temperature
If power reduction is implemented to prevent overheating during critical heat flux, then equipment temperature decreases, but power availability is reduced during critical operations
Solution Approach 1:
The movable fins provide dynamic adaptation to critical heat flux conditions, allowing the system to maintain full power operation when needed by adjusting the cooling regime. The fins can reposition to create beneficial flow patterns that enhance cooling efficiency without requiring power reduction
4Loss of energy
If additional protrusions are added to increase heat exchange surface area, then cooling efficiency improves, but device complexity increases
Solution Approach 1:
Instead of adding fixed protrusions that increase structural complexity, the patent uses movable fins that can change position. This dynamic approach provides adjustable heat exchange surface area without permanent structural additions, maintaining simpler device architecture while achieving enhanced cooling when needed
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
The device ensures continuous operation at full power by enhancing heat exchange through fin position changes, preventing overheating and maintaining contact with the cooling fluid, thus safeguarding electrical equipment from damage.
Implementation Method 1
the cooling fluid 93 circulating around or on the electrical equipment 92 will change phase, that is to say that the cooling fluid 93 will change from the liquid state 93a to the gaseous state 93b in contact with the wall 921 of the circuit of the electrical equipment 92
Implementation Method 2
a circulation channel containing a flow of a cooling fluid, said cooling fluid being a two-phase fluid comprising a liquid phase and a gaseous phase
Implementation Method 3
at least one fin disposed within said channel and extending from said wall, each fin having a proximal end integral with said wall and a distal end opposite the proximal end, each fin being movable between a close position and a far position
Data Source
Figure 1a~1b
Figure 2~3
Figure 4~5
AI summary
The invention relates to a device (1) for cooling electrical equipment (2), said device (1) comprising: - a circulation channel (11) containing a flow (110) of a two-phase cooling fluid (111); - a thermally conductive wall (13) for separating the channel (11) and the electrical equipment; - at least one fin (15) disposed within the channel (11) and extending from the wall (13), each fin (15) being configured to be in a position close to the wall when the temperature of the fin (15) is below a predetermined temperature, and to be in a position far from the wall when the temperature of the fin (15) is greater than or equal to the predetermined temperature. Such a device makes it possible to efficiently cool electrical equipment without having to reduce its power output during periods of very high heat loss.