旋转式室温磁制冷系统的研制及实验研究

Design and Development of Rotary Room Temperature Magnetic Refrigeration System

本文以高效、紧凑为设计重点,研制了一台新型双层同心旋转磁体式室温磁制冷系统,整机空间尺寸约720 mm×440mm×230 mm。系统采用双层同心嵌套式Halbach磁体组,磁体轴心处可获得0.18~1.72 T的磁场强度;主动磁回热器的填充长度为120 mm,填充工质为Gd球(直径0.375~0.50 mm),填充质量440 g;换热流体为pH=8的碱性溶液。基于该实验装置,开展了不同流动时间占比(100%,80%,60%)工况下实验研究。其中,在利用系数为0.84与运行频率为0.35 Hz时,流动时间占比80%的时序获得最大无负荷制冷温跨20.2 K。在利用系数为1.26和运行频率为0.35 Hz时,室温磁制冷系统在10.8 K制冷温跨下获得60 W的制冷量,并在5.2 K的制冷温跨下获得最大制冷量80 W。

In this work,we have developed a new double ring concentric rotating magnet type room temperature magnetic refrigeration system with high efficiency and compact structure as the design focus.The whole machine space size is about 720 mm×440 mm×230 mm.The doublelayer concentric nested Halbach magnet group is adopted,and the magnetic field intensity at the magnet axis is between 0.18 T and 1.72 T.The filling length,filling weight,and diameter of the filling working medium Gd ball of the active magnetic regenerator are 120 mm,440 g and 0.375~0.5mm respectively,and the heat exchange fluid is an alkaline solution with pH=8.Based on this system,we have conducted comparative experiments on the timing strategies of 100%,80%and60%of the flow time ratio,respectively.The maximum no-load temperature span of the system reaches 20.2 K,under the working conditions of 80%,0.84 and 0.35 Hz in the proportion of flow time,utilization factor,and operating frequency,respectively.It is worth noting that when the utilization factor is selected as 1.26 and the operating frequency is 0.35 Hz,the system obtains a large cooling capacity of 60 W and 80 W under different temperature spans of 10.8 K and 5.2 K,respectively.