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Numerical Simulation Research on the Entire Process of a Cryostat Based on J-T Refrigeration Machine

Qi Wang^1,3, Dongxu Han^1,3, Bo Gao^2,3,*, Siqi Liu^2,3,4, Haiyang Zhang^2,3, Peng Wang¹, Dongliang Sun^1,*, Bo Yu⁵

1 School of Mechanical Engineering, Beijing Institute of Petrochemical Technology, 19 Qingyuan North Road, Daxing District, Beijing, 102617, China
2 State Key Laboratory of Cryogenic Science and Technology, 29 Zhongguancun East Road, Haidian District, 100190 Beijing, China
3 TIPC-LNE Joint Laboratory on Cryogenic Metrology Science and Technology, Technical Institute of Physics and Chemistry (TIPC), Chinese Academy of Sciences (CAS), Beijing, 100190, China
4 School of Metallurgy, Northeastern University, Shenyang, 110819, China
5 School of Petroleum Engineering, Yangtze University, Wuhan, 430100, China

The International Conference on Computational & Experimental Engineering and Sciences 2024, 29(4), 1-2. https://doi.org/10.32604/icces.2024.012509

Abstract

The pre-cooled J-T refrigerator is an important device for achieving low temperatures in the 2K temperature zone through mechanical refrigeration. It provides a stable and reliable low-temperature environment in the 2K-5K temperature range and ensures the accuracy of the low-temperature thermostat in the reference temperature measuring device. In this paper, the SAGE model and ESS model were established to determine the cooling capacity at 2K using the pre-cooling J-T cycle of a two-stage G-M refrigerator, which is utilized in the low-temperature thermostat of a 2-5K reference temperature measuring device. Thermodynamic analysis of the J-T throttling process was conducted, and experimental data from the literature were employed to validate the models. Using this model, key operating parameters such as the high-pressure pressure (P_H) and pre-cooling temperature (T_pre) in the J-T cycle are analyzed and optimized. The results of the J-T refrigerator cycle were integrated with the low-temperature thermostat, and the cooling process and stability of the entire low-temperature thermostat system were simulated. It is found that when the final pre-cooling temperature T_pre remains constant, the cooling capacity Q_c first increases and then decreases with the high pressure PH. To meet specific cooling capacity requirements, optimal values for the final pre-cooling temperature T_pre and high pressure PH can be chosen to minimize the total power consumption of the J-T refrigerator. Considering the lower cooling temperature of the cryostat, the J-T refrigerator is capable of providing an 11mW cooling capacity for the cryostat at 2.2K, with a minimum no-load temperature reaching 2.13K. These research findings offer optimization strategies and theoretical insights for the refrigeration cycle process of the low-temperature thermostat in the reference temperature measuring device.

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