工作频率及环境温度对往复式磁制冷效果的影响

Influence of Operating Frequency and Ambient Temperature on Reciprocating Magnetic Cooling

为分析不同工作频率和室温环境对往复式室温磁制冷系统制冷温跨的影响,设计了一套以Gd颗粒(粒径:0.3~0.5mm)为磁工质的往复式室温磁制冷系统,并结合活性蓄冷器的换热特点对往复式室温磁制冷系统的制冷温跨进行实验分析。测量了在1.5 T的永磁铁场强下,室温磁制冷机在不同工作频率(0.07、0.12、0.16、0.19、0.22 Hz)及在不同室温工况(14.5、15.9、16.7、18.1℃)蓄冷器冷、热端温度的变化情况。研究表明,当工作频率为0.22 Hz时,系统的最大制冷温跨为12.8℃,并发现当Gd的温度低于其居里温度20℃时,不同室温对有限时间内磁制冷系统的制冷量无影响。

To analyze the influence of different working frequencies and room temperatures on the cooling span of a reciprocating room- temperature magnetic refrigeration system, a setup for such a system was designed with granular Gd （particle size： 0.3-0.5 mm） as the magnetic working mass. The cooling temperature of the reciprocating room-temperature magnetic refrigeration system was then analyzed, combined with the heat transfer characteristics in the active cooler during the experiment. A 1.5 T permanent magnet field strength was maintained, and the changes in the cold-and hot-end temperatures of the cold accumulator were measured at different operating frequencies （0.07, 0.12, 0.16, 0.19, 0.22 Hz） and room temperatures （ 14.5, 15.9, 16.7, 18.1 ℃ ）. The results show that, when the operating frequency is 0.22 Hz, the maximum refrigeration temperature span of the system is 12.8 ℃. Further, when the Gd temperature is lower than the Curie temperature of 20 ℃, the room temperature has no effect on the cooling capacity of the magnetic refrigeration system over a finite time period.