Rare-Earth Regenerator Particles for Cryogenic Gas Permeability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional regenerator materials for cryogenic refrigerators face challenges in achieving high-density filling and maximizing the contact surface area with the operating medium gas, such as helium, which affects the refrigerating performance and reliability, especially at extremely low temperatures.
Innovation Solution
Rare-earth regenerator material particles with specific size and shape characteristics, including an average particle size of 0.01 to 3 mm, a high proportion of particles with an aspect ratio of 2 or less, and a significant proportion of depressed portions on the surface, are developed to enhance packing density and contact surface area, utilizing manufacturing methods like the Rotary Disc Process and rotary nozzle process to produce these particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If spherical particles are used for high-density filling, then packing density is improved, but contact surface area with He gas is reduced
Solution Approach 1:
The patent applies asymmetry by introducing non-spherical shapes (cubes, irregular particles) with specific surface area enhancements. These asymmetric particles provide both high packing density and increased contact surface area with He gas, resolving the contradiction between spherical shape benefits and surface area requirements.
Solution Approach 2:
The patent changes particle size parameters and shape parameters to optimize performance. By controlling particle size distribution and introducing shape variations, the patent achieves high-density filling while maintaining large contact surface area for heat exchange with He gas.
2Area of stationary object
If smaller particles are used to increase contact surface area, then contact surface area is improved, but permeability of He gas decreases
Solution Approach 1:
The patent applies local quality by creating particles with surface features (protrusions, depressions, rough surfaces) that increase contact area locally without reducing overall particle size. This maintains He gas permeability while enhancing contact surface area for heat exchange.
Solution Approach 2:
The patent segments particles into specific size distributions, combining finer particles for surface area with coarser particles for permeability. This segmentation allows the regenerator material to simultaneously achieve high contact surface area and adequate gas flow permeability.
3Quantity of substance
If particles are filled under high pressure to increase density, then packing density is improved, but particle crushing occurs causing clogging
Solution Approach 1:
The patent uses particles with rounded surfaces and smooth contours that resist crushing under filling pressure. The curved surfaces distribute stress more evenly, preventing particle fragmentation and subsequent clogging while achieving high packing density.
Solution Approach 2:
The patent employs composite particle structures with enhanced mechanical strength, combining materials or structures that maintain integrity under high filling pressure. This prevents particle crushing and ensures reliable long-term operation without clogging.
Data Source
AI summary
Provided is a group of rare-earth regenerator material particles having an average particle size of 0.01 to 3 mm, wherein the proportion of particles having a ratio of a long diameter to a short diameter of 2 or less is 90% or more by number, and the proportion of particles having a depressed portion having a length of 1/10 to ½ of a circumferential length on a particle surface is 30% or more by number. By forming the depressed portion on the surface of the regenerator material particles, it is possible to increase permeability of an operating medium gas and a contact surface area with the operating medium gas.