Study of Dul'nev's Model for the Thermal and Radiative Properties of Open-Cellular Porous Materials

Abstract

To establish a model for predicting the thermal and radiative properties of open-cellular porous materials, the potentialities of a Dul'nev cubic unit cell model are examined. First, the accuracy of Dul'nev's formula for the conductive effective thermal conductivity is quantitatively evaluated and then, on the basis of Dul'nev's model, analytical expressions for the radiative properties, such as the extinction coefficient, albedo and asymmetry factor of a phase function, are derived, and their validities are confirmed. Finally, the feasibility of using dul'nev's unit cell model to predict the heat transfer characteristics of a conducting-radiating, open-cellular porous ZrO₂ layer is indicated.