Composite materials for Ericsson-like magnetic refrigeration cycle
Composite materials for Ericsson-like magnetic refrigeration cycle
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DOI：
10.1063/1.364166
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发表时间：
1997-01-15
影响因子：
3.2
通讯作者：
Chahine, R
中科院分区：
文献类型：
--
作者：
Smaili, A;Chahine, R
理想的磁埃里克森制冷循环应在整个制冷范围内具有恒定的作为温度的函数的感生磁熵变。为了使用复合材料实现这一条件，开发了一种数值方法来确定此类制冷剂中组分材料的最佳比例。本文研究了组分数（n）的增加对复合制冷剂（Δ S-com）磁熵变恒定性的影响，并提出了一些新的复合制冷剂。为此目的，已经使用Gd-1-x-Dy-x（其中x=0、0.12、0.28、0.49和0.70）合金。Delta S的值是根据平均场理论以及这些合金在0.1-7 T磁场范围和200-300 K温度范围内的实验磁化曲线计算得出的。然后提出了两组复合材料作为制冷剂，分别在240-290 K和210-290 K的温度范围内工作。然后使用单个Gd-Dy合金的Δ S数据来计算复合材料的最佳质量比。所得Δ S-com在所需的温度范围内实际上是恒定的，并且对于两个相应的组，其值为8.0和7.3 J/kg K。结果表明，随后增加的n可以改善的Delta S-com值的恒定性，因此，相应的制冷剂应该更有效地运行。因此，发现对于第一组和第二组，n的适当值分别为3和4。(C)1997年美国物理研究所。
The ideal magnetic Ericsson refrigeration cycle should have a constant induced magnetic entropy change as a function of temperature over the whole refrigeration range. To realize this condition using composite materials, a numerical method has been developed to determine the optimum proportions of the component materials in such refrigerants. This paper investigates the effects of increasing the number (n) of the components on the constancy of the magnetic entropy change of the composite (Delta S-com), and suggests some new composite refrigerants. For this purpose, the Gd-1-x-Dy-x (with x=0, 0.12, 0.28, 0.49, and 0.70) alloys, have been used. The values of Delta S have been calculated both from mean-field theory as well as from experimental magnetization curves of these alloys, in the 0.1-7 T magnetic field range and the 200-300 K temperature range. Two sets of composite materials have then been proposed as refrigerants, operating, respectively, over the temperature range 240-290 K and 210-290 K. The Delta S data of the individual Gd-Dy alloys were then used to calculate the optimum mass ratio of the composites. The resultant Delta S-com is practically constant in the required temperature range and amounts to 8.0 and 7.3 J/kg K for the two respective sets. The results show that a subsequent increase of n can improve the constancy of the value of Delta S-com and, hence, the corresponding refrigerant should operate more efficiently. Thus, it is found that the appropriate values of n are 3 and 4, respectively, for the first and the second set. (C) 1997 American Institute of Physics.