Modeling the Heating of Composites with Absorbing Fillers of Various Shapes in a Microwave Chamber with a C-Slit Emitter

Based on mathematical modeling, the heating of composites with absorbing fillers of various shapes made of silicon carbide and carbon fiber in a microwave chamber with a waveguide-slit emitter is studied. The results of numerical modeling in the form of a temperature field distribution in the composite volume are presented. The influence of the shape and size of absorbing fillers on the temperature, uniformity and heating rate of composites at a given microwave power is determined. It has been established that the use of composites with absorbing fillers made of silicon carbide makes it possible to obtain more uniform heating of composites compared with fillers made of carbon fiber. The best indicators in terms of temperature, uniformity and heating rate are obtained for a composite with fillers in the form of rods of rectangular and circular cross-sections. The use of carbon fiber as absorbing fillers is limited---due to local microwave heating of individual layers of fillers – to samples of small geometric sizes. The microwave power level for forced heating of a high-energy radio-absorbing composite has been determined to achieve the required temperature and heating rate. An algorithm for stepwise control of microwave power with respect to the composite temperature has been developed to solve the problem of heating it to the binder curing temperature and heat treatment to relieve mechanical stresses.