ISSN Online: 2379-1748
7th Thermal and Fluids Engineering Conference (TFEC)
SJR:
0.152
SNIP:
0.14
CiteScore™::
0.5
Indexed in
CALCULATION OF RADIATION DISTRIBUTION FACTORS FROM GEOMETRICAL FACTORS
Resumo
A formal analytical relationship is presented between the view factors used in the net-exchange (B-H or J-G) method and the distribution factors used in the Monte Carlo ray-trace (MCRT) method for computing radiant heat exchange among diffuse grey surfaces in the absence of a participating medium. The relationship is validated for the case of a long, evacuated duct having a regular hexagonal cross-section. It is demonstrated that the relationship can be used to obtain high-accuracy estimates of radiation distribution factors without the need of carrying out a costly ray-trace if the view factors are known and reflectivity is relatively small. The
relationship has the form of an n-term Markov chain, where n is the number of surface elements into which the
enclosure has been divided. The successive terms of the chain represent increasingly higher orders of approximation. We demonstrate that, as the absorptivity of the enclosure walls increases, the number of terms required to obtain an accurate result decreases and relatively few terms are required to obtain satisfactory results.
Palavras-chave:
Radiation Heat Transfer