Thermal Runaway and Hot Spots Under Controlled Microwave Heating

摘要

Numerical simulations of the thermal runaway have been carried out within the simplest model of spherically symmetrical temperature distribution over a sample undergoing microwave heating. It was shown that the thermal runaway can be avoided under conditions of controllable microwave heating. However when a control of microwave power is based on the surface temperature of a sample, a stable regime of heating can only be achieved if an increase of the electromagnetic absorptivity of a sample material with temperature growth is not too sharp. In the opposite case it is necessary to use a very good thermal insulation arrangement. In the intermediate case a development of the thermal runaway is sensitive to the rate of microwave heating.