Near field radiative heat transfer between macro-scale metallic surfaces at cryogenic temperatures

0549394 - ÚPT 2022 RIV GB eng J - Journal Article
Králík, Tomáš - Hanzelka, Pavel - Musilová, Věra - Srnka, Aleš - Urban, Pavel
Near field radiative heat transfer between macro-scale metallic surfaces at cryogenic temperatures.
Cryogenics. Roč. 113, January (2021), č. článku 103156. ISSN 0011-2275. E-ISSN 1879-2235
R&D Projects: GA ČR(CZ) GA20-00918S
Institutional support: RVO:68081731
Keywords : Heat transfer * Thermal radiation * Cryogenics * Near-field
OECD category: Optics (including laser optics and quantum optics)
Impact factor: 2.134, year: 2021
Method of publishing: Open access
https://www.sciencedirect.com/science/article/pii/S0011227520301582

Knowledge of radiative heat transfer between bodies at various temperatures is essential for efficient design of cryogenic devices. Radiative far-field heat transfer is commonly taken into account. Nevertheless, when the distance d between components of a device becomes small, smaller than the characteristic wavelength of Planck's far field thermal radiation, an additional heat transfer caused by thermal electromagnetic near-field starts to play a role. At cryogenic temperatures and micrometric distances, this near field heat transfer can exceed the far-field one by orders of magnitude. We report experimental results on near-field and far-field heat fluxes q transferred across a plane parallel vacuum gap d between pair of identical copper (RRR = 10) and tungsten (RRR = 1.5) samples. The heat flux q was measured over the distances d = 1–100 μm and for various temperatures T2 = 15–80 K of the hot sample and the temperature T1 down to 5 K of the cold one. We compare the copper and tungsten data with previously published results for normal metals Nb and NbN. For each pair of identical samples, the measured values of near-field thermal conductance of vacuum gap, KT = q/(T2 − T1), collapse into nearly a single dependence on the gap size d. Thus for specific metallic surfaces, this relation enables estimate the near field heat flux at cryogenic temperatures over micrometric distances.
Permanent Link: http://hdl.handle.net/11104/0325412