干式量热器测量隔热结构热性能实验研究

Experimental research on measuring thermal performance of thermal insulation structure with dry calorimeter

设计搭建一套基于两级G-M制冷机的圆筒形干式量热器装置,首先分析铜制和铝制量热杆对装置误差的影响,其次对3组不同的隔热结构进行热性能实验测试,并研究不同的边界温度对隔热结构热性能的影响。实验结果表明,铝制量热杆测量误差更小;在高真空环境下,隔热泡沫对复合结构的绝热性能影响不大,MLI或者VDMLI起主要绝热作用;分别改变冷边界温度和热边界温度对隔热结构热性能的影响不同,热边界温度一定,冷边界温度由20 K增大到100 K时,通过隔热结构的热流密度略有减小;冷边界温度一定,热边界温度由300 K增大到350 K时,通过隔热结构的热流密度急剧增大。

A cylindrical dry calorimeter based on a two-stage G-M refrigerator was designed and built. The influence of calorimetric rods made of copper or aluminum on measurement uncertainty was analyzed,and the thermal performance of three different thermal insulation systems was tested and discussed. In addition, the influence of different boundary temperatures on the thermal performance of the FMLI was studied. The experimental results show that the measurement uncertainty of the aluminum calorimetric rod is less than the copper calorimetric rod. In a high vacuum environment, the foam has little effect on the thermal performance of the FMLI, and MLI or VDMLI plays a critical role in thermal insulation performance. The thermal performance of the FMLI is different when the cold boundary temperature and the warm boundary temperature are changed respectively. When the warm boundary temperature is constant and the cold boundary temperature increases from 20 K to 100 K, the heat flux through the FMLI decreases slightly. In contrast the heat flux through the FMLI increases sharply when the cold boundary temperature is constant and the warm boundary temperature increases from 300 K to 350 K.