Calculation of Heating Patterns in Microwave Sintering using a 3D Finite-Difference Code

Abstract

Analysis of heating patterns in microwave sintering experiments provide information on the contributions of the various heat transfer components to the overall temperature pattern. Measured temperature patterns provide limited information on overall effects. Numerical simulations provide a cost effective way from which the effect of geometry, material properties and the presence of stimulus such as SiC rods or sheets on the heating pattern can be studied separately. Parametric studies allow us to identify the most significant properties and provide guidelines for the routine successful utilization of microwave sintering experiments. These guidelines may also facilitate the scale up and commercialization of microwave sintering.

In this paper we describe a thermal model that calculates the temperature distribution in ceramic samples and insulation under realistic microwave sintering conditions. The calculation process involves a two-step procedure. The first step is to calculate the microwave power deposition in the sample and surrounding insulation. 3D FDTD calculations, described in a companion paper[1,2], are used for this purpose. The other step involves calculation of the temperature distribution using a 3D finite-difference heat-transfer program developed in our Departments[3]. Results illustrating the effect of thickness of insulation and the placement of SiC rod susceptors in picket-fence arrangement are presented.