Molecular dynamics insights into contaminant phase transition and regenerator blockage mechanisms
Year: 2025
Type: article
Abstract: Pulse Tube Refrigerators are widely used in cryogenic applications due to their high reliability and long lifespan. However, the release of contaminant gases from internal components, which leads to performance degradation, remains a challenging issue. This study employs molecular dynamics simulations to analyze the behavior of N 2 , CO 2 , and H 2 O within the regenerator. The results indicate that as the temperature decreases, more contaminants desublimate and deposit. Below the phase transition temperature (T pt ), more than 95 % of contaminants deposit within 3 mesh layers. For H 2 O above the T pt , over 98 % attaches to the wire mesh during airflow passes through. N 2 forms a monolayer on the wire surface, while CO 2 at 140 K and H 2 O at 220 K exhibit solid growth on the windward side, with these solids being transported to regions of lower airflow velocity as temperatures rise. Additionally, solid contaminants can sublimate into gas, diffusing toward colder regions. Lower temperatures reduce the likelihood of resublimation occurring. There is less than a 2 % ratio that N 2 and CO 2 will sublimate at 80 K and 180 K, and the migration distance is N 2 > CO 2 > H 2 O. This study provides a theoretical foundation for improving regenerator design and restoring the performance of degraded refrigerators.
Source: Applied Thermal Engineering
Institution: University of Shanghai for Science and Technology
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,660
Award: G5262964143
OpenAlex ID: W4416535909