BOUNDARY INTEGRAL SOLUTION OF THERMAL RADIATION EXCHANGES IN AXISYMMETRIC FURNACES

A numerical algorithm is presented for predicting thermal radiation exchanges among surface elements in axisymmetric geometries. The algorithm is based on the Galerkin boundary-element formulation, enhanced with the best ideas of computer graphics used for image clipping and image object sorting to detect shadowing effects, and incorporating an adaptive integration scheme to improve the accuracy and efficiency of the computation of the radiation exchange kernels with abrupt discontinuities due to blockages of various complexities. Detailed descriptions of the algorithm and numerical implementation are given. Numerical results are compared with analytical solutions whenever available. The coupling of the surface radiation exchange calculations with those for Marangoni convection and heat conduction, as occurring in materials processing systems, is also discussed.