An active convective 4He heat switch. (December 2022)

• Record Type: Journal Article
• Authors: May, Andrew J.; Azzoni, Susanna; Melhuish, Simon; Piccirillo, Lucio; Seal, Daniel; Sweetnam, Thomas; Winnicki, Joseph
• Is Part Of: Cryogenics. Volume 128(2022)
• Publication Date: 2022-12
• Subjects: Heat switch -- Thermal switch -- Convection -- 4He -- Active switch; Low temperature engineering -- Periodicals; Low temperature research -- Periodicals; 536.56
• DOI: 10.1016/j.cryogenics.2022.103585
• Languages: English
• ISSNs: 0011-2275

Abstract

Highlights: Design, modelling, and experimental demonstration of novel cryogenic switch. Switch based on convective heat transfer inside a permanently sealed switch. Switch is actively controlled by the heating of a charcoal cryopump. We report the experimental demonstration of the switch. We report CFD analysis of the switch. Novel analytical model which shows far better agreement than previous models. Abstract: The design and experimental demonstration are reported of an active convective heat switch suitable for use at cryogenic temperatures. The switch is mechanically simple, relatively inexpensive, and requires no moving parts, instead being operated entirely using heaters. The working gas used is 4 He in a closed cycle and, as such, the switch requires no external gas connections. Closed conductances on the order of 50 mW/K have been demonstrated with residual open conductances on the order of 0.4 mW/K. Novel modelling is presented which shows excellent agreement with the experimental data and significant improvement over existing models.