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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

Estimation method of optimum profiles of absorption coefficient for gray analyses in real gas systems enclosed by gray walls

Get access (open in a dialog) DOI: 10.1615/IHTC12.4940
6 pages

Abstract

A new method is proposed to estimate the mean path lengths of radiative energy between emitting gas elements and the surrounding gray, non-black walls in non-gray gas systems.The new mean path lengths are substituted to the equation of Patch's effective mean absorption coefficient to estimate the profiles of equivalent absorption coefficient for gray radiative heat transfer analysis.Using the profiles of absorption coefficient, gray analysis is shown to give similar results with the exact ones of the corresponding non-gray analysis.In the present method, the path length is estimated as the sum of mean direct path length between the gas volume and the surrounding walls and the mean path length the radiative energy emitted by the gas volume travels after reflected by the walls.The method is applied to two-dimensional model furnace systems, and the accuracy of the results of gray analyses is shown to be improved from the gray analyses using absorption coefficient derived by conventional Hottel chart.