scholarly journals Evaluation of Radiative Heat Transfer in High-Temperature Porous Insulation Materials by Using Diffusion Approximation

Netsu Bussei ◽  
2015 ◽  
Vol 28 (4) ◽  
pp. 179-184 ◽  
Author(s):  
Tatsuya Kobari ◽  
Junnosuke Okajima ◽  
Atsuki Komiya ◽  
Shigenao Maruyama
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Radiative Heat Transfer ◽  
Diffusion Approximation ◽  
Radiative Heat ◽  
Insulation Materials

scholarly journals The Treatment of Nongray Properties in Radiative Heat Transfer: From Past to Present

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Michael F. Modest
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Radiative Heat Transfer ◽  
Historical Development ◽  
Radiative Heat ◽  
State Of The Art ◽  
Participating Media ◽  
Box Models ◽  
Property Data ◽  
Gradual Development

Radiative heat transfer in high-temperature participating media displays very strong spectral, or “nongray,” behavior, which is both very difficult to characterize and to evaluate. This has led to very gradual development of nongray models, starting with primitive semigray and box models based on old experimental property data, to today's state-of-the-art k-distribution approaches with properties obtained from high-resolution spectroscopic databases. In this paper a brief review of the historical development of nongray models and property databases is given, culminating with a more detailed description of the most modern spectral tools.

Analysis of Combined Conductive-Radiative Heat Transfer in a Two-Dimensional Rectangular Enclosure With a Gray Medium

1988 ◽  
Vol 110 (2) ◽  
pp. 468-474 ◽  
Author(s):  
W. W. Yuen ◽  
E. E. Takara
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Diffusion Approximation ◽  
Radiative Heat ◽  
Transfer Problem ◽  
Numerical Procedure ◽  
Numerical Data ◽  
Two Dimensional ◽  
One Dimensional ◽  
Benchmark Solutions

Combined conductive–radiative heat transfer in a two-dimensional enclosure is considered. The numerical procedure is based on a combination of two previous techniques that have been demonstrated to be successful for a two-dimensional pure radiation problem and a one-dimensional combined conductive–radiative heat transfer problem, respectively. Both temperature profile and heat transfer distributions are generated efficiently and accurately. Numerical data are presented to serve as benchmark solutions for two-dimensional combined conductive–radiative heat transfer. The accuracy of two commonly used approximation procedures for multidimensional combined conductive–radiative heat transfer is assessed. The additive solution, which is effective in generating approximation to one-dimensional combined conductive–radiative heat transfer, appears to be an acceptable empirical approach in estimating heat transfer in the present two-dimensional problem. The diffusion approximation, on the other hand, is shown to be generally inaccurate. For all optical thicknesses and conduction-radiation parameters considered (including the optically thick limit), the diffusion approximation is shown to yield significant errors in both the temperature and heat flux predictions.

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