Finite element analysis of effect of grain orientation on the thermal conduction of h-BN ceramics

Abstract

Study of thermal conduction process of ceramics by experimental and theoretical model analysis methods is complicated and non-intuitive. In this work, to analyze the influence mechanism of h-BN grain orientation on the thermal conduction of h-BN ceramics, new mesoscale finite element models considering the anisotropy in the thermal conductivity of h-BN grain were established based on random sequential adsorption method and periodic boundary condition. And the accuracy of the finite element models was verified by theoretical model and experimental results. The heat flux vector and temperature distributions intuitively show that the orientation of h-BN grains will significantly affect the thermal conduction process of the ceramics by affecting the heat flow path. The heat flow will propagate mainly along the “thermal conducting pathways” formed by the h-BN grains when the h-BN layer direction shows small angle with the external temperature difference direction, otherwise, h-BN grains will act as barriers to the heat conduction.