Open Access

ARTICLE

Numerical Investigation of CO₂ Contaminant Transport and Deposition in an In-Line Pulse Tube Cryocooler

Hao Zhu^1,2, Xi Chen^1,2,*, Pengcheng Qu^1,2, Yifan Zhu^1,2, Haoyi Wang^1,2, Yingxia Qi^1,2
1 School of Energy and Power Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai, China
2 Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai, China
* Corresponding Author: Xi Chen. Email:

Frontiers in Heat and Mass Transfer https://doi.org/10.32604/fhmt.2026.076127

Received 14 November 2025; Accepted 06 January 2026; Published online 21 January 2026

Abstract

Pulse tube cryocoolers are widely employed in cryogenic systems, where gas contamination has become a critical factor limiting both performance and service life. To further investigate the condensation behavior of contaminants, this study develops a two-dimensional axisymmetric model of a linear-type cryocooler to simulate the transport and deposition processes of trace CO₂, evaluating the impact of contamination on system pressure drop under various operating conditions. Results indicate that CO₂ diffusion is primarily driven by concentration gradients. The CO₂ deposition rate increases markedly at low temperatures and high concentrations, with over 90% of deposition occurring in the cold-end heat exchanger. Under different concentration distributions, dry ice predominantly accumulates in the cold-end heat exchanger; however, notable differences emerge in the pulse tube. In the uniform distribution case, CO₂ tends to deposit along the inner wall of the pulse tube, whereas in the gradual release scenario, deposition mainly occurs on the cold-end flow straightening mesh screen. Dry ice deposition significantly increases the pressure drop across the system and decreases the pressure wave amplitude, resulting in a degradation of cooling capacity. This study lays a foundation for further investigation into the thermal properties of contaminant layers and provides theoretical guidance for optimizing cold-end components to improve contamination resilience.

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Keywords

Pulse tube cryocoolers; carbon dioxide; dry ice deposition; CFD

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