Additive Manufactured Cryogenic Heat Exchanger Surface
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Solution Overview
Problem
Cryogenic cooling systems face challenges with interfacial thermal resistance, particularly between liquid helium and metals, leading to inefficiencies in heat transfer at extremely low temperatures, and existing solutions like sintered surfaces have stochastic performance and low thermal conductivity.
Innovation Solution
The use of additive manufacturing to create heat exchangers with a surface-to-volume ratio of at least 105 l/m, featuring recursive surface structures and extended thermal conduction paths, which enhance thermal conductivity and predictability while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If sintered surfaces are used to increase surface area for heat transfer, then the surface-to-volume ratio is improved, but the thermal conductivity deteriorates due to low conductivity in sintered material
Solution Approach 1:
The heat exchanger surface is segmented into multiple discrete protrusions rather than using a continuous sintered layer. Each protrusion is a separate additive manufacturing feature with controlled geometry, allowing thermal conduction paths to be optimized within each segment while collectively providing large surface area.
Solution Approach 2:
The invention changes the geometric parameters of the surface structure by creating protrusions with specific height, width, and spacing parameters through additive manufacturing. This allows precise control of both surface area (improving heat transfer) and thermal conduction paths (maintaining conductivity), resolving the contradiction between surface area and thermal conductivity.
2Area of stationary object
If sintered surfaces are used to increase surface area, then heat transfer surface is improved, but the performance becomes stochastic and unpredictable
Solution Approach 1:
The continuous sintered surface is segmented into discrete protrusion elements that can be individually controlled during additive manufacturing. This segmentation allows each element's geometry to be precisely defined by digital models, ensuring consistent reproduction across manufacturing batches and eliminating the stochastic variability inherent in sintering processes.
Solution Approach 2:
The invention replaces the mechanical sintering process with additive manufacturing technology. This substitution eliminates the inherent variability of sintering by using digitally controlled layer-by-layer construction, where each protrusion's dimensions, position, and shape are precisely specified in the digital model, ensuring repeatable and predictable performance.
3Device complexity
If conventional heat exchanger designs are used, then structural simplicity is maintained, but heat transfer efficiency deteriorates due to interfacial thermal resistance
Solution Approach 1:
The invention introduces curved protrusion shapes with optimized contours rather than flat or simple geometric forms. The curved surfaces increase the effective heat transfer area while the additive manufacturing process maintains structural integrity. This curvature optimization improves heat transfer efficiency without significantly complicating the overall device structure.
Solution Approach 2:
The invention transitions from two-dimensional flat heat exchanger surfaces to three-dimensional protruding structures. By adding the vertical dimension with protrusions of various heights, the effective heat transfer surface area is dramatically increased while the base structure remains relatively simple. This dimensional enhancement improves heat transfer efficiency without proportionally increasing device 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
This approach significantly improves heat transfer efficiency between liquid cryogens and solid materials, achieving consistent performance across various sizes and versions of cryogenic cooling systems by optimizing the surface-to-volume ratio and thermal conductivity.
Implementation Method 1
extended thermal conduction paths, which enhance thermal conductivity
Implementation Method 2
interfacial thermal resistance, also called the Kapitza resistance. It means the inherent difficulty of making thermal-energy-carrying phonons cross the border between two materials
Implementation Method 3
The material has a surface-to-volume ratio of at least 105 l/m... recursive surface structures and extended thermal conduction paths, which enhance thermal conductivity
Data Source
AI summary
A heat exchanger material for use in heat exchangers of cryogenic cooling systems comprises solid material rendered into a final form in an additive manufacturing process. The heat exchanger material has a surface-to-volume ratio of at least 105 l/m.