Pulse Tube Cooler Heat Exchanger for Helium Flow Rectification
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Solution Overview
Problem
The existing pulse tube cryogenic coolers suffer from reduced cooling efficiency due to inadequate heat conductivity between the heat exchanger and the housing, leading to inefficient heat transfer and increased heat entry into the pulse tube.
Innovation Solution
The implementation of a heat exchanger with a first laminating part where porous plates with piercing holes and spacers are laminated, and a second laminating part with lower part mesh members, enhancing heat exchange efficiency by rectifying helium gas flow and increasing the surface area for heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional heat exchanger structure is used in the pulse tube cryogenic cooler, then the device complexity is reduced, but the heat exchange efficiency deteriorates leading to increased heat entry into the pulse tube
Solution Approach 1:
The heat exchanger is divided into multiple porous plates (first porous plate, second porous plate, third porous plate) with different mesh sizes and configurations. Each plate segment handles different aspects of heat exchange, allowing the system to improve overall heat transfer efficiency while managing complexity through modular segmentation of the heat exchange function
Solution Approach 2:
Different regions of the heat exchanger are designed with locally optimized properties: the first porous plate has a first mesh size for initial heat exchange, the second porous plate has a second mesh size for intermediate exchange, and the third porous plate has a third mesh size for final exchange. This local differentiation of mesh sizes and plate structures optimizes heat transfer at each stage while addressing the overall efficiency requirement
2Ease of manufacture
If the heat exchanger has insufficient heat conductivity, then the manufacturing is simplified, but the cooling efficiency deteriorates due to inefficient heat transfer
Solution Approach 1:
The heat exchanger utilizes porous plates with controlled porosity and mesh structures. The porous material provides large surface area for heat transfer within a compact volume, significantly improving heat conductivity and cooling efficiency. The porous structure allows efficient thermal contact between the heat exchanger and the pulse tube while maintaining manufacturability through standard porous material fabrication techniques
Solution Approach 2:
The heat exchanger employs composite construction combining multiple porous plate materials with different thermal and flow properties. This composite approach optimizes both heat transfer performance and manufacturability by selecting materials that balance thermal conductivity, mechanical strength, and fabrication ease
3Temperature
If a simple heat exchanger structure is used, then the device complexity is reduced, but the temperature achievable by the cooler deteriorates (higher temperature)
Solution Approach 1:
The multi-plate porous structure segments the heat exchange process into multiple stages, with each porous plate contributing to progressive cooling. This segmentation enables achieving lower temperatures (4.15 K) by cumulative heat extraction across multiple interfaces, rather than relying on a single simple heat exchanger structure
Solution Approach 2:
The porous plates introduce an additional dimensional aspect to heat exchange by utilizing the three-dimensional porous network structure. This allows heat transfer to occur through multiple pathways and surfaces simultaneously, enhancing the effective heat exchange area and enabling lower temperature achievement without simply increasing the linear dimensions of a conventional heat exchanger
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 configuration improves the heat exchanging property and cooling efficiency of the pulse tube cryogenic cooler, achieving a lower temperature of 4.15 K at 1 W load compared to 4.51 K with conventional designs, thereby enhancing the overall cooling performance.
Implementation Method 1
a first laminating part where porous plates with piercing holes and spacers are mutually laminated
Implementation Method 2
a heat exchanger provided at an end part of a pulse tube... improves the heat exchanging property
Implementation Method 3
a second laminating part where lower part mesh members are laminated... increasing the surface area for heat transfer
Implementation Method 4
a pulse tube cryogenic cooler... achieving a lower temperature of 4.15 K at 1 W load
Data Source
AI summary
A pulse tube cryogenic cooler, includes: a pressure vibration generating device configured to generate pressure vibration in operation gas; a regenerator connected to the pressure vibration generating device; a pulse tube connected to the regenerator; a phase control mechanism connected to the pulse tube; and a heat exchanger provided at an end of the pulse tube; wherein the heat exchanger includes a first laminating part where porous plates having piercing holes and spacers are mutually laminated; and a second laminating part where lower part mesh members are laminated.