Heat transfer mechanism and characteristics of lightweight high temperature ceramic cellular sandwich

Abstract

Consider the severe thermal loads in thermal engineering applications of lightweight ZrO2 and ZrB2 corrugated sandwich structures, here, their heat transfer mechanism and characteristics are originally explored in this work. Finite element (FE) models for heat transfer of ZrO2 and ZrB2 sandwiches, sandwiches filled with insulation material and the corresponding bulk ceramics are respectively well established. The insulation efficiency, temperature gradient, thermal short effect and thermal-mechanical coupling effect are well calculated and analyzed. It is found that cavity radiation heat flux is increased with the height, leading to low insulation efficiency. The insulation material can block the cavity radiation, and hence can remarkably enhance the insulation efficiency and improve the temperature uniformity. Low temperature gradient is found in ZrO2 and ZrB2 sandwiches, while, remarkable temperature gradients are found in sandwiches filled with insulation material. With the increasing height, the insulation effect is improved, while the mechanical properties are weakened, suggesting pronounced thermal-mechanical coupling effect between loading bearing capacity and insulation effect. The heat transfer mechanism and characteristic revealed here provide the thermal basis for engineering applications of the ZrO2 and ZrB2 cellular sandwiches.