TLM simulation of microwave hybrid sintering of multiple samples in a multimode cavity

Abstract

SUMMARYMicrowave heating technology is a powerful mean to ensure successful sintering of ceramic materials. In sintering experiments, low loss insulators, conductors and high-loss ceramics are microwaved so as to get optimal mechanical and structural properties. It is known that low-loss ceramic materials such alumina and zirconia exhibit long waiting time before reaching a critical coupling temperature at which microwaves can be readily absorbed. On the other hand, some ceramics such as silicon carbid have a high loss factor and therefore can be used as a process stimulus for microwave sintering of microwave transparent ceramics. Furthermore, successful sintering experiments often require the use of carefully designed insulating structure in order to minimize thermal gradients caused by heat loss from surfaces. All these problems have led to the introduction of microwave hybrid heating (MHH) schemes using higher dielectric loss susceptors, insulation or coating. Since MHH depend mainly on human expertise, the optimization of sintering experiments will certainly benefit from numerical simulations. The transmission line matrix (TLM) is used to study two MHH schemes where both a susceptor and an insulating matrix were, respectively, used as process stimulus for microwave heating of multiple alumina samples within a threedimensional multimode cavity. The effects of such MHH schemes and target settings on electric field distribution and power absorption rates are reported in this paper.

Microwave Sintering: Fundamentals and Modeling

“…A TLM study of microwave hybrid heating, elucidating the influence of high‐loss susceptor materials on the power deposition, is reported in Ref. .…”

Dimensional soft tissue thermal injury analysis using transmission line matrix (TLM) method

“…In recent years, the TLM method has been applied to a wide range of applications related to electromagnetics [36], sound wave propagation [37,38], and mass and heat diffusion [23,25]. The TLM method is explicit, one step, and unconditionally stable.…”

“…An analytical model was also applied to estimate the thermal skin burns due to contact with the hot expelled gases from the airbag or prolonged contact with the hot airbag itself [22]. TLM has been used by many authors to investigate heat diffusion in various materials ranging from semiconductor devices [23,24] to ceramics [25]. TLM has proven to be a powerful technique with bodies of complex geometries [26] and each time non-linearity was difficult to handle.…”