Influence of radiative heat transfer model on the computation of residual stresses in glass tempering process

During glass tempering, residual stresses are caused by the temperature gradient appearing between the surface and the core of the glass. It is therefore necessary to have an accurate knowledge of the heat transfer occurring during the process to obtain an accurate estimation of the residual stresses. Since glass is a semitransparent material, radiative heat transfer takes place inside the glass in addition to the conductive heat transfer. In this paper, we implemented 1-D thermomechanical models using different methods for the computation of the radiative effects inside the glass: Rosseland approximation, P1 approximation and back ray tracing. Thermal and residual stresses results are compared to experimental results available in the literature to investigate the effects of the different methods on the heat transfer and mechanical behavior. We found that P1 approximation and back ray tracing are in good agreement with the experimental results. Finally, a numerical investigation is done by changing different parameters for which the experimental results are not available.