Heat transfer in rarefied gases: Critical assessments of thermal conductance and accommodation of argon in the transition regime

Abstract

Heat transfer measurements from thin filaments to argon gas in cells of cylindrical symmetry are made under extreme clean surface conditions so that known constant values of α, the thermal accommodation coefficient, on the filament pertain over the full range of pressures, 0.01-40 Torr. The results are used in an attempt to assess merit of principal theoretical treatments of heat transfer in the transition regime by extracting α according to each treatment and comparing results with the presumed known value. Before relative merit of the theories can be assigned with confidence, a wider differentiation in the α values obtained is needed. It is expected that this may result when similar experiments for the higher α gases, krypton and xenon, can be completed and critically examined.