COMBINED CONVECTION AND RADIATION HEAT TRANSFER IN NON-GRAY PARTICIPATING MEDIA IN A DIFFERENTIALLY HEATED SQUARE CAVITY

2019 ◽  
Vol 11 (6) ◽  
pp. 489-507 ◽  
Author(s):  
Shashikant Cholake ◽  
S. P. Venkateshan ◽  
Thirumalachari Sundararajan
Keyword(s):  
Heat Transfer ◽  
Radiation Heat Transfer ◽  
Radiation Heat ◽  
Square Cavity ◽  
Participating Media ◽  
Combined Convection

Simulation of Radiation Heat Transfer of Three Dimensional Participating Media by Radiative Exchange Method

2008 ◽  
Author(s):  
Mohammad Hadi Bordbar ◽  
Timo Hyppa¨nen
Keyword(s):  
Heat Transfer ◽  
Balance Equation ◽  
Radiation Heat Transfer ◽  
Three Dimensional ◽  
Radiation Balance ◽  
Scattering Media ◽  
Radiation Heat ◽  
Exchange Method ◽  
Participating Media ◽  
Radiative Exchange

This paper describes the theoretical bases of the Radiative Exchange Method, a new numerical method for simulating radiation heat transfer. By considering radiative interaction between all points of the geometry and solving the radiation balance equation in a mesh structure coarser than the structure used in computational fluid flow calculation, this method is able to simulate radiative heat transfer in arbitrary 3D space with absorbing, emitting and scattering media surrounded by emitting, absorbing and reflecting surfaces. A new concept is introduced, that of the exchange factors between the different elements that are necessary for completing the radiative balance equation set. Using this method leads to a set of algebraic equations for the radiative outgoing power from each coarse cell being produced and the result of this set of equations was then used to calculate the volumetric radiative source term in the fine cell structure. The formulation of the exchange factor for a three-dimensional state and also a mesh size analysis that was conducted to optimize the accuracy and runtime are presented. The results of this model to simulate typical 3D furnace shape geometry, is verified by comparison with those of other numerical methods.

Modeling Radiation Heat Transfer With Participating Media in Solid Oxide Fuel Cells

2005 ◽  
Vol 3 (1) ◽  
pp. 62-67 ◽  
Author(s):  
J. D. J. VanderSteen ◽  
J. G. Pharoah
Keyword(s):  
Heat Transfer ◽  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Accurate Determination ◽  
Radiation Heat Transfer ◽  
Transport Processes ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Radiation Heat ◽  
Participating Media

Solid oxide fuel cell (SOFC) technology has been shown to be viable, but its profitability has not yet been seen. To achieve a high net efficiency at a low net cost, a detailed understanding of the transport processes both inside and outside of the SOFC stack is required. Of particular significance is an accurate determination of the temperature distribution because material properties, chemical kinetics, and transport properties depend heavily on the temperature. Effective utilization of the heat can lead to a substantial increase in overall system efficiency and decrease in operating cost. Despite the extreme importance in accurately predicting temperature, the SOFC modeling community appears to be uncertain about the importance of incorporating radiation into their models. Although some models have included it, the majority of models ignore radiative heat transfer. SOFCs operate at temperatures around or above 1200 K, where radiation effects can be significant. In order to correctly predict the radiation heat transfer, participating gases must also be included. Water vapor and carbon dioxide can absorb, emit, and scatter radiation, and are present at the anode in high concentrations. This paper presents a simple thermal transport model for analyzing heat transfer and improving thermal management within planar SOFCs. The model was implemented using a commercial computational fluid dynamic code and includes conduction, convection, and radiation in a participating media. It is clear from this study that radiation must be considered when modeling solid oxide fuel cells. The effect of participating media radiation was shown to be minimal in this geometry, but it is likely to be more important in tubular geometries.

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