Radiative heat transfer estimation in pipes with various wall emissivities

26th International Cryogenic Engineering Conference & International Cryogenic Materials Conference 2016

材料科学;物理学

Robin, Langebach^1 ; Christoph, Haberstroh^1

Technische Universitaet Dresden, Bitzer-Professur fuer Kaelte-Kryo- und Kompressorentechnik, Dresden

01062, Germany^1

关键词: Asymptotic values;    In-pipe;    Model equations;    Pipe walls;    Plane-parallel plates;    Radiative heat transfer;    Thermal budgeting;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/171/1/012096/pdf
DOI  :  10.1088/1757-899X/171/1/012096

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Radiative heat transfer is usually of substantial importance in cryogenics when systems are designed and thermal budgeting is carried out. However, the contribution of pipes is commonly assumed to be comparably low since the warm and cold ends as well as their cross section are fairly small. Nevertheless, for a first assessment of each pipe rough estimates are always appreciated. In order to estimate the radiative heat transfer with traditional "paper and pencil" methods there is only one analytical case available in literature - the case of plane-parallel plates. This case can only be used to calculate the theoretical lower and the upper asymptotic values of the radiative heat transfer, since pipe wall radiation properties are not taken into account. For this paper we investigated the radiative heat transfer estimation in pipes with various wall emissivities with the help of numerical simulations. Out of a number of calculation series we could gain an empirical extension for the used approach of plane-parallel plates. The model equation can be used to carry out enhanced paper and pencil estimations for the radiative heat transfer through pipes without demanding numerical simulations.