Gas Gap Heat Switch Assembly Using Thermal Contraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gas gap heat switches face challenges in achieving reliable and efficient heat transfer at low temperatures, particularly in miniaturized forms, due to limitations in the design of interdigitated conductors and poor heat transfer properties of collinear designs at low temperatures.
Innovation Solution
A method for forming a gas gap heat switch involving collinearly arranged conductors with connecting members having lower thermal conductivity and expansion coefficients than the conductors, allowing for a controlled thermal contraction to create a small gap at low temperatures, enabling effective heat transfer through a thermally conductive gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If interdigitated conductor design is used, then heat transfer surface area is increased, but manufacturing complexity and miniaturization difficulty increase
Solution Approach 1:
The heat switch is divided into multiple discrete components: first and second conductors, first and second connecting members, and a chamber. This segmentation allows each component to be manufactured separately with standard techniques and then assembled, reducing overall manufacturing complexity while maintaining the functional requirements for heat transfer surface area.
Solution Approach 2:
The collinear conductors are nested within the chamber formed by the connecting members. This nested arrangement allows the conductors to be positioned precisely along a common axis while being contained within a compact structure, achieving efficient heat transfer geometry without complex external mounting arrangements.
2Ease of manufacture
If collinear conductor arrangement is used, then manufacturing simplicity is improved, but heat transfer performance at low temperatures deteriorates due to gap size limitations
Solution Approach 1:
The gap size between conductors is controlled by changing the temperature parameter. At high temperatures, the gap is larger allowing for easier assembly and accommodation of manufacturing tolerances. At low operating temperatures, thermal contraction reduces the gap to optimal dimensions for heat transfer, thereby achieving both manufacturing simplicity and heat transfer performance through temperature-dependent parameter adjustment.
Solution Approach 2:
The connecting members are specifically selected to have lower thermal expansion coefficients than the conductors. This differential thermal expansion ensures that when the assembly is cooled from high temperature (assembly state) to low temperature (operating state), the conductors contract more than the connecting members, automatically reducing the gap between conductors to optimal dimensions for heat transfer while maintaining alignment and structural integrity.
3Strength
If high thermal conductivity connecting members are used, then assembly robustness is improved, but unwanted heat transfer through connecting members increases
Solution Approach 1:
Different thermal conductivity properties are assigned to different parts of the system. The conductors are made of high thermal conductivity material for efficient heat transfer along their length, while the connecting members are specifically selected to have lower thermal conductivity to minimize parasitic heat transfer through the chamber walls. This local differentiation of thermal properties optimizes the overall heat transfer performance by directing heat flow through the intended path while blocking unwanted alternative paths.
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 allows for reliable and efficient heat transfer while maintaining a robust separable thermal connection, achieving smaller separation between conductors than previous designs, thus improving performance at low temperatures.
Implementation Method 1
the connecting members forming the chamber each have a coefficient of thermal expansion that is less than that of the conductors such that, when the conductors are cooled to a second temperature which is below the first temperature, the length of the conductors along the major axis decreases with respect to the length of the chamber along the major axis so as to form a gap between the proximal ends of the conductors
Implementation Method 2
the gas inside the chamber facilitates heat transfer between the conductors by conduction
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A method for forming a gas gap heat switch is provided comprising the following steps: (a) providing first and second conductors, and first and second connecting members, wherein the connecting members each have a thermal conductivity at least five times smaller than that of the conductors when at a temperature of 100K; (b) fusing the first conductor to the first connecting member and the second conductor to the second connecting member; (c) aligning the conductors such that the first and second conductors extend along a common major axis; (d) bringing proximal ends of the aligned conductors into contact with each other when said conductors are at a first temperature; and (e) joining the first connecting member to the second connecting member so as to form a chamber around at least the proximal ends of the conductors. The connecting members forming the chamber each have a coefficient of thermal expansion that is less than that of the conductors such that, when the conductors are cooled to a second temperature which is below the first temperature, the length of the conductors along the major axis decreases with respect to the length of the chamber along the major axis so as to form a gap between the proximal ends of the conductors. The switch is also arranged to selectively provide a thermally conductive gas into the chamber when in use to cause operation of the switch.