Cryocooler
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cryocoolers face a challenge in minimizing dead volume while preventing excessive pressure drops in the working gas flow path, which can decrease refrigeration capacity.
Innovation Solution
The implementation of a gas-guiding flow channel that connects the housing gas flow path and the displacer upper gas flow path when the displacer is at top-dead center, reducing the dead volume and pressure drop by optimizing the geometry of the channel to ensure smooth gas flow through the regenerator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If the dead volume in the upper gas chamber is minimized, then the refrigeration capacity is improved, but the pressure drop in the working gas flow path increases excessively
Solution Approach 1:
The upper gas chamber is segmented into multiple flow paths including a housing gas flow path, a displacer upper gas flow path, and a gas-guiding flow channel. This segmentation allows the gas to flow through multiple smaller channels rather than one large chamber, reducing dead volume while maintaining adequate flow areas to limit pressure drops
Solution Approach 2:
A gas-guiding flow channel is introduced as an intermediary structure that connects the housing gas flow path and the displacer upper gas flow path. This intermediate channel guides the working gas smoothly between the two main flow paths, ensuring continuous gas flow and preventing excessive pressure drops while minimizing the overall dead volume
2Volume of stationary object
If the gas flow path geometry is optimized to reduce dead volume, then the refrigeration capacity increases, but the gas flow efficiency decreases due to excessive pressure drops
Solution Approach 1:
Different regions of the upper gas chamber are given different local qualities through the design of specialized flow paths. The housing gas flow path, displacer upper gas flow path, and gas-guiding flow channel each have optimized geometries suited to their specific functions, ensuring efficient gas flow through each local region while collectively minimizing total dead volume
Solution Approach 2:
The gas-guiding flow channel and other flow path components are designed with smooth curved transitions rather than sharp angles or abrupt changes. This curvature optimization ensures smooth gas flow through the regenerator and throughout the upper gas chamber, reducing turbulence and pressure drops while maintaining compact geometry
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 effectively minimizes dead volume and pressure drop, maintaining the refrigeration capacity of the cryocooler by ensuring efficient gas flow and reducing the risk of excessive pressure drops during the reciprocation of the displacer.
Implementation Method 1
a gas-guiding flow channel formed in at least either the housing bottom surface or the displacer upper surface constituting a portion of the upper gas chamber, and interconnecting the housing gas flow path and the displacer upper gas flow path
Implementation Method 2
The variable volume that by the relative movement of the displacer with respect to the cylinder is formed between the two is employed as the working-gas expansion chamber. Appropriate synchronizing of the expansion-chamber volume change and pressure change enables the expander to produce coldness.
Data Source
AI summary
A cryocooler includes: a housing furnished with a housing bottom surface; a displacer furnished with a displacer upper surface between the housing bottom surface and which an upper gas chamber is formed, and being enabled to reciprocate axially with respect to the housing; a housing gas flow path formed in the housing and opening onto the upper gas chamber; a displacer upper gas flow path formed in the displacer and opening onto the upper gas chamber; and a gas-guiding flow channel formed in at least either the housing bottom surface or the displacer upper surface constituting a portion of the upper gas chamber, and interconnecting the housing gas flow path and the displacer upper gas flow path when the displacer is positioned at top-dead center in its axial reciprocation.