Transient numerical simulation of annealing process in a conjugate combined radiation conduction heat transfer

Abstract

The annealing time is an important affecting factor in the performance of many furnaces. The present work deals with the transient simulation of annealing process in a cubic furnace in which a solid element is placed in its center. As the working gas can have some radiating features, a set of governing equations including the energy balance with the radiative transfer equation (RTE) for the gray radiating medium and the conduction equation inside the solid product are numerically solved with progressing in time. Numerical results which are validated against both analytical and theoretical findings in the literature demonstrate that during the starting period, a high rate of radiant energy transfers into the solid body even at small optical thickness. This behavior which hastens the rate of heat transfer at low values of the radiation conduction parameter, causes a fast annealing process in which the solid body warms up to its maximum temperature. Moreover, it is revealed that the rate of heat transfer is an increasing function of radiation-conduction parameter.