小型传导冷却低温系统热分析与实验研究

Thermal analysis and experimental study of small conduction-cooled cryogenic system

传导冷却型低温系统中,各结构组件间的热平衡过程是以固体间热传导的形式向制冷机实现热量传递。由于各冷却部件降温条件的差异,会导致系统内部温度分布不均匀,影响被测样品性能测量,需对系统结构开展热分析与实验研究。借助ANSYS软件,建立了小型低温系统三维模型并进行了热分析,结果显示,预期系统最低温度为2.38 K,冷屏最大温差不超过1.0 K,样品台最大温差不超过0.1 K。同时,采用一套2.2 W@4.2 K双级制冷机作为冷源,完成了低温系统降温与精准控温实验。实验结果表明,冷屏误差不超过1.5 K,样品台误差不超过0.01 K,与模拟分析结果吻合良好,满足系统要求,验证了传导冷却低温系统热分析方法的准确性以及实验装置测温的可靠性,为类似装置的热分析及其设计提供了参考。

In a conduction-cooled cryogenic system,the thermal equilibrium process between the structural components is to transfer heat to the refrigerator in the form of heat transfer between solids.Due to the difference of cooling conditions of each cooling component,the temperature distribution inside the system will be uneven,which will affect the performance measurement of the tested sample.Therefore,it is of great significance to conduct thermal analysis and experimental research for the system.A three-dimensional model of small cryogenic system was established and the thermal analysis was carried out based on ANSYS software.The result shows that the expected minimum temperature of the system is 2.38 K,the maximum temperature difference of the cold shield is not more than 1.0 K,and the maximum temperature difference of the sample stage is not more than 0.1 K.Meanwhile,a cooling and precise temperature control experiment was completed by a set of 2.2 W@4.2 K two-stage refrigerator as the cold source.The experimental result shows that the error of the cold shield is less than 1.5 K and the error of the sample stage is not more than 0.01 K,which is in good agreement with the simulation results and meets the system requirements.It verified the accuracy of the thermal analysis of the conduction-cooled cryogenic system and the reliability of the temperature measurement of the experimental device,and can provide a reference for the thermal analysis and technical design of similar devices.