Some critical remarks about the radiative heat transfer in air frame cavities according to EN ISO 10077-2

33rd UIT (Italian Union of Thermo-fluid dynamics) Heat Transfer Conference

物理学;力学

Cuccurullo, G.^1 ; Giordano, L.^1

Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II 132, Fisciano (SA)

84084, Italy^1

关键词: Combined heat transfer;    Equivalence criteria;    Equivalent thermal conductivities;    International standards;    Radiative heat fluxes;    Radiative heat transfer;    Radiative parameters;    Thermal Performance;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/655/1/012025/pdf
DOI  :  10.1088/1742-6596/655/1/012025

学科分类：力学，机械学

来源: IOP

【 摘 要 】

Thermal performances of windows frames are established, in Europe, by the international standard UNI EN ISO 10077-2:2012. The standard introduces an equivalent thermal conductivity for air frame cavities thus simplifying the original combined heat transfer problem to a merely two-dimensional conductive one. The equivalence is referred to a rectangular cavity and is not able to fully recover the same radiative heat flux involved in the original problem. In view of that, the paper is focused on the radiative heat transfer taking place in the air cavities and aims to check if different equivalence criteria could lead to improved results. Thus, numerical tests involving an accurate description of radiative heat transfer in air cavities are compared to the simplified fully-conductive one provided by the standard. Results show that different criteria lead to quite different results. The optimal criterion turns out to depend on both geometrical and surface radiative parameters. It is also shown that, in any case, a proper radiative resistance but not the one suggested by the ISO 10077 should be adopted.