A STEP FORWARD TO THE NETWORK METHOD FOR RADIATION HEAT TRANSFER ANALYSIS IN ENCLOSURES

Abstract

In this paper, we proposed a network method for studying radiation in enclosures that expresses radiosities and irradiations as functions of the blackbody emissive powers and of the radiation fluxes entering the enclosure through its partially transparent walls. The results obtained are used to express the radiation heat flow exchange between two surfaces and the net radiation heat flux leaving each of the enclosure surfaces as a function of these true driving forces for radiation heat transfer. This reduces the problem to its essential, as these are the true driving forces for the radiation heat transfer. Net radiation heat fluxes leaving each of the enclosure surfaces form the system of equations from which the relevant radiation heat transfer parameters for each surface are evaluated. The approach proposed is based on elementary matrices operations, the main attention being paid to the problem setting (just essential) thus leaving the calculations to the calculator or to the computer. It is introduced for enclosures with all opaque walls and illustrated by one example, and then extended to enclosures with partially transparent walls. The proposed simplifying and unifying approach is relevant not only to radiation heat transfer analysis and calculations, but also to pedagogical purposes, retaining attention on the essential of the radiation heat transfer problem formulation, setting aside intermediate/auxiliary variables calculations that are usually aversive, fastidious, detractive, and prone to errors.