Monte Carlo method is widely used for the computation of total exchange areas in radiative heat transfer processes. This paper covers the development of a method based on classical probability distribution function and random numbers to evolve a computer algorithm for determination of total exchange areas in three dimensional furnace enclosures with emitting and absorbing surfaces.The method involves simulation of the pathways of a large number of beams carrying finite amount of energy from a specified surface zone inside an enclosure and tracing their routes until they get absorbed. Equations for beam tracings and intersection criteria have been developed for plane walls, rectangular paralleopiped and cylinders. Computed total exchange areas were found to be within 0.1% of theoretically calculated values of known shape factors for similar surface zones. The equations once verified can be applied to more complicated geometries by combining these basic shapes using zone method. Total exchange areas thus obtained can then be used in heat balance equations for multiple surface and gas zones to find the temperature and heat flux profile inside the furnace enclosure. These will be especially useful in modelling and simulation of reaction furnaces of unconventional shapes.
