RADIATIVE HEAT-TRANSFER IN 3-DIMENSIONAL ENCLOSURES OF COMPLEX-GEOMETRY BY USING THE DISCRETE-ORDINATES METHOD

This paper presents a new algorithm based on the discrete-ordinates me thod for the calculation of radiative transfer in three-dimensional, g ray participating media of complex geometry. The key feature of the ne w technique is the utilization of general characteristic equations whi ch replace the classical spatial differencing schemes. These equations result from the formal integration of the radiative transfer equation followed by an averaging procedure on the surfaces. This feature enab les the use of tetrahedral grids which can be fitted to any geometrica l enclosure. Furthermore, the new algorithm does not generate the nume rical oscillations and negative intensities that can be encountered wi th the traditional method. The method uses the techniques of recogniti on of neighboring cells. It is directly compatible with the solution o f the conservation equations by finite element techniques. This paper is a sequel to a previous paper recently published by the same authors on two-dimensional cases. An assessment of the method is given by com paring the results for simple cases with those obtained by other autho rs. Application is then made to more complicated cases. The method is proved to be general and accurate. (C) 1998 Elsevier Science Ltd. All rights reserved.