Combined heat transfer of radiation and conduction in stacked radiation shields for vacuum insulation panels

Abstract

Combined heat transfer of radiation and conduction considering depthwise conduction phenomena in stacked radiation shields for vacuum insulation panels (VIPs) having an artificial core structure is investigated. The purpose of this study is to establish a reliable analysis method for actual shield design. A one-dimensional problem is first analyzed. Actual two-dimensional problem is simplified for theoretical modeling and the depthwise conduction around contact spot is further considered. Test radiation shields are manufactured using press molding process with SUS 304 (AISI grade 304) plates, since this sample depicts the parametric effects well. Measurement of the effective thermal conductivity is performed with a VGHP apparatus. While various analytical and numerical models predict the effective thermal conductivity in the case of this specific specimen within about 40% error, the combined heat transfer analysis considering depthewise conduction phenomena is accurate within 10% error and it is thus recommended in estimating the effective thermal conductivity of stacked radiation shields. (C) 2011 Elsevier B.V. All rights reserved.