Modeling the effective thermal conductivity of hollow bricks at high temperatures

In this work, we derive a model for the anisotropic effective thermal conductivity of bricks based on the unit cell model approach. The presented model considers conduction and surface-to-surface radiation in the brick. Four different radiation models are presented, compared, and validated using fully resolved computational fluid dynamics simulations for three different brick profiles and experiments. Good agreement with fully resolved computational fluid dynamics simulations with and without radiation is found. The validated model was then applied in a global sensitivity study and to simulate the temperature distribution in brick stacks in a tunnel kiln segment under firing conditions.