Measurement of apparent thermal conductivity of regenerator materials in 4–20 K temperature range. (June 2021)

• Record Type: Journal Article
• Authors: Yang, Biao; Xi, Xiaotong; Liu, Xuming; Xu, Xiafan; Chen, Liubiao; Wang, Junjie
• Is Part Of: Cryogenics. Volume 116(2021)
• Publication Date: 2021-06
• Subjects: Regenerator material -- Apparent thermal conductivity -- Thermal conduction factor -- Liquid-helium temperature range -- Pulse tube cryocooler; Low temperature engineering -- Periodicals; Low temperature research -- Periodicals; 536.56
• DOI: 10.1016/j.cryogenics.2021.103300
• Languages: English
• ISSNs: 0011-2275

Abstract

Highlights: A cryogenic apparent thermal conductivity measurement apparatus was developed. The apparent thermal conductivities of GOS, HoCu2, Er3 Ni, and lead were tested. The natural convection effect of helium-4 was measured. The effects of temperatures (4–40 K) and pressures (0–2 MPa) were investigated. Abstract: The axial heat leakage between the cold and hot ends of the regenerator caused by the huge temperature difference is an important part of the cryocooler loss, where the apparent thermal conductivity of regenerator materials is the key parameter that determines the heat leakage. At present, only the apparent thermal conductivity of stainless steel wire mesh, lead and copper sphere above 80 K can be obtained, while measurement results for lower temperatures or other materials are currently not available. A low-temperature apparent thermal conductivity measurement apparatus for regenerator materials has been developed, and the apparent thermal conductivities of sphere-type material (GOS, HoCu2, Er3 Ni, and lead), mesh-type material (stainless steel wire mesh), and helium-4 under various pressures have been measured. When the regenerator is in a vacuum state (below 10 -4 Pa), the experimental results show that the thermal conduction factors (the ratio of the apparent thermal conductivity of the filled regenerator to that of the material itself) are 0.02 for GOS in 4–10 K temperature range, 0.28 for HoCu2, 0.43 for Er3 Ni in 4–20 K temperature range, 0.005 for lead sphere and 0.13 for stainless steel wire mesh in 10–40 K temperature range, respectively. However, when the regenerator is filled with helium-4, the thermal conduction factor values increase by one order of magnitude.