Liquid Metal Thermal Switch for Dynamic Thermal Conduction Control
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Solution Overview
Problem
Existing thermal control systems face limitations in efficiency, rate of temperature change, maximum heat load, and precision due to the inability to effectively control thermal conduction, particularly in systems with fluctuating heat loads or requiring precise temperature control.
Innovation Solution
A thermal switch utilizing a thermally conductive liquid and a movable actuator to control the flow of liquid metal between plates, allowing for precise and rapid adjustment of thermal conductivity, with a rangeability of up to 600:1, and capable of supporting structural loads without external movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thermal conduction is controlled by regulating heat generation or convection/radiation, then temperature control is achieved, but thermal conduction itself cannot be changed during operation, limiting efficiency and rate of temperature change
Solution Approach 1:
The patent changes the thermal conductivity parameter of the thermal path by introducing a thermally conductive liquid (mercury) that can be moved between a reservoir and a channel. When mercury is in the channel, thermal conduction is high; when moved to the reservoir, thermal conduction is reduced. This allows dynamic adjustment of thermal conduction properties during operation, resolving the contradiction between maintaining stable thermal conduction and enabling rapid temperature change.
2Loss of energy
If a combination of modulated heating with constant cooling is used, then temperature control is achieved, but system efficiency is limited due to inability to control thermal conduction
Solution Approach 1:
The patent introduces a dynamic element (movable mercury) that can actively adjust the thermal conduction state based on heating/cooling requirements. Instead of using constant cooling with modulated heating, the system can dynamically switch between high and low thermal conduction states, allowing more efficient thermal management by matching the thermal path conductivity to the actual thermal load conditions, thereby reducing energy loss.
3Reliability
If prior art thermal switches are used to change thermal conduction, then some control is achieved, but shortcomings in thermal performance, cost, reliability, and ease of implementation remain
Solution Approach 1:
The patent extracts the thermal control function from complex mechanical contact systems or gas-filled gap systems and implements it using a simple liquid metal displacement mechanism. The mercury is moved between a reservoir and a channel using simple actuators (solenoids, bellows, or thermal expansion), eliminating the need for complex mechanical contacts or pressure manipulation systems, thereby improving reliability while reducing implementation complexity.
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 solution provides improved efficiency and reliability in thermal control, enabling precise, rapid, and proportional control of thermal conduction, suitable for applications with fluctuating heat loads and high precision requirements.
Implementation Method 1
a channel defining a gap between the first and second plate... thermally conductive liquid is allowed to flow from the first reservoir to the channel
Implementation Method 2
The actuator is coupled to the first reservoir and the channel and is moveable between a first state and a second state corresponding to the on-state and the off-state of the thermal switch
Data Source
AI summary
A thermal switch having an on-state and an off-state is provided. First and second plates are composed from a thermally conductive material. The first and second plates are connected to form an internal cavity having a channel defining a gap between the first and second plate. The first reservoir is coupled to the channel and contains a thermally conductive liquid. The actuator is coupled to the first reservoir and the channel and is moveable between a first state and a second state corresponding to the on-state and the off-state of the thermal switch, respectively. Thermally conductive liquid is allowed to flow from the first reservoir to the channel when the actuator is in the first state and allowed to flow from the channel to the first reservoir when the actuator is in the second state.