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ISSN Online: 2377-424X

ISBN Print: 0-89116-130-9

International Heat Transfer Conference 6
August, 7-11, 1978, Toronto, Canada

SHAPE FACTOR DETERMINATION FOR NON-LAMBERT SURFACES

Get access (open in a dialog) DOI: 10.1615/IHTC6.4160
pages 331-334

Abstract

Real surfaces, generally, do not conform to the Lambert cosine law. The shape factor which is used in radiation heat transfer, expresses the fraction of heat radiated by a surface which is intercepted by another surface. The concept of the shape factor as expressed by the known equations implies validity of cosine law for radiation power distribution. The analysis of emissive power distribution for real surfaces, for which experimental results exist, points to the more general expression of the shape factor. The shape factor integrators, which the authors have developed from infinitesimal to finite Lambert surface radiative heat exchange, are modified and adapted for Non-Lambert surface emission. The instrument is for general use; it immediatly gives values of the shape factor for Lambert surfaces, as well as values for given real "isotropic" surfaces. The shape factor integration can be performed (for both Lambert and Non-Lambert surfaces) on surface models or on real surfaces "in loco".