Accession Number : AD0659945

Title :   AN EXAMINATION OF THE METHOD OF REGIONAL AVERAGING FOR RADIATIVE TRANSFER BETWEEN CONCENTRIC SPHERES,

Corporate Author : BROWN UNIV PROVIDENCE R I DIV OF ENGINEERING

Personal Author(s) : Hunt,Brian L.

Report Date : JUL 1967

Pagination or Media Count : 40

Abstract : Approximate equations were derived according to the method of regional averaging for the radiative transfer in an absorbing and emitting medium between two concentric spheres. 3-region, 2-region and Milne-Eddington approximations were considered. The approximate equations were solved for two types of problem (a) no heat generation with different wall temperatures and (b) uniform heat generation with equal wall temperatures. In the solutions, the absorption coefficient of the intervening medium was assumed constant. The approximate solutions were compared with exact values obtained by earlier workers. It was found that for case (a), the 3-region and 2-region approximations give good agreement but the Milne-Eddington results were poor. For case (b), it was found that the 2-region approximation was poor, the Milne-Eddington approximation was quite good for radius ratios approaching unity but otherwise poor and that the 3-region approximation was good for small radius ratios but breaks down as the planar limit was approached. (Author)

Descriptors :   (*HEAT TRANSFER, SPHERES), APPROXIMATION(MATHEMATICS), THERMAL RADIATION, DIFFERENTIAL THERMAL ANALYSIS

Subject Categories : Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE