4～10 K温区活性炭对氦气的吸附特性及其在4 K温区回热式制冷机中的潜在应用（英文）  

Adsorption characteristics of helium on an activated carbon at 4-10 K and its prospective application in 4 K-class regenerative cryocoolers

作　　者：席肖桐 王珏 陈六彪[1,2] 郭璐娜 杨彪 周远 王俊杰[1,2] XI Xiao-tong;WANG Jue;CHEN Liu-biao;GUO Lu-na;YANG Biao;ZHOU Yuan;WANG Jun-jie(Chinese Academy of Sciences Key Laboratory of Cryogenics,Technical Institute of Physics and Chemistry,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院理化技术研究所,低温工程学重点实验室,北京100190 [2]中国科学院大学,北京100049

出　　处：《新型炭材料》2019年第6期524-532,共9页New Carbon Materials

基　　金：国家自然科学基金(51706233,51427806,U1831203);中国科学院战略性先导科技专项(XDA15010400);中国科学院前沿科学重点研究计划(QYZDY-SSW-JSC028);中国科学院低温工程学重点实验室青年科技创新项目(CRYOQN201706)~~

摘　　要：活性炭对氦气的吸附量数据是低温领域中吸附式制冷机、气隙式热开关和制冷机回热器研究中的重要参数。活性炭作为制冷机蓄冷材料时,其对氦气的高吸附量导致的高比热有望解决4 K制冷机目前磁性蓄冷材料蓄冷能力严重不足的瓶颈问题,另外还存在着无磁性优点。然而,目前液氦温区活性炭对氦气的吸附量还没有充足的实验数据。本文通过搭建实验台,测试了活性炭在4~10 K,0.5~3.5 MPa范围内的吸附量数据,并计算了吸附热。另外,为了充分验证使用吸附的氦气作为蓄冷材料的可行性,分别计算和测试了比热与流动阻力。结果表明,吸附氦气后的活性炭比热明显高于常规的回热器材料,其流动阻力也与目前Er3Ni等颗粒材料相当,能够适用于4 K制冷机回热器的蓄冷材料。Adsorption data of helium on activated carbon at low temperatures are essential for its use in sorption coolers, gas-gap heat switches and the regenerators of cryocoolers. Especially when an activated carbon is used as the regenerator material in a cryocooler, the high specific heat caused by the high amount of adsorbed helium is expected to solve the bottleneck problem that the conventional 4 K cryocooler regenerator material suffers. It also has the advantage of being non-magnetic. However, the amounts of helium adsorbed on on the activated carbon in the temperature range of 4-10 K are low. In this paper, the adsorption isotherms of helium on a coconut shell-based activated carbon in the pressure-temperature range(4-10 K, 0.5-3.5 MPa) were measured with a self-built adsorption apparatus, from which the isosteric heats of adsorption and the specific heats of the activated carbon with adsorbed helium were calculated. The helium flow resistance through the activated carbon was also measured to evaluate its feasibility in a cryocooler. Results indicate that the isotherms are type I and can be fitted by the Langmuir adsorption model. The isosteric heats of adsorption are around 279 J/mol and change little with the amount of adsorbed helium. The specific heats of the activated carbon with adsorbed helium depend on the adsorption temperature and pressure, and their average values at 4-10 K are the highest among the commonly used solid regenerator materials(lead, SS, Er3Ni and HoCu2) and gaseous helium under the pressures investigated, which are ascribed to the high amount of helium adsorbed and the high heat of adsorption of helium on the activated carbon. The helium flow resistance through a material is related to its size and surface roughness and the value through the activated carbon is moderate among the four commonly used solid regenerator materials. Activated carbon with adsorbed helium is suitable as a regenerator material of cryocoolers because of its high specific heat and moderate flow resistance.

关 键 词：吸附特性 回热器 活性炭 吸附氦气 4K级回热式制冷机 

分 类 号：TQ127.1+1[化学工程—无机化工]