Parametric Investigation of Microwave Assisted Materials Processing

Abstract

Microwave is a significant component of the electromagnetic spectrum having longer wavelengths and an ability to generate heat within materials with a characteristic dielectric and magnetic properties. Microwave heating is a unique phenomenon that has a substantial untapped potential in newlinethe field of materials processing. Microwave heating comes with many advantages in materials processing domain, which primarily includes faster processing-time and minimal environmental impact. Its use was limited to ceramic drying and sintering applications until it was demonstrated that newlinemetals could be processed using microwaves by using an indirect heating. Even though several applications of microwave energy in materials processing domain have been reported, its industrial use is still not popular. This can be attributed to limited understanding of the microwave-heating newlinephenomenon and dedicated devices to use microwave irradiation in materials processing. newlineFurthermore, numerical simulation of microwave heating and investigation of the parameters having potential effect on the microwave heating is still a widely open domain of research. newlineThis work has been carried out in three major phases. In the first phase, parametric numerical simulation was carried out to compare three important microwave susceptors identified from the literature, viz. silicon carbide, alumina and coal based on temperature rise. Out of the three susceptors, coal attained highest temperature (901 oC) upon interacting with microwave radiation. However, it was also noted that the temperature distribution in coal was non-uniform owing to poor thermal newlineconductivity. To quantify the impact of input parameters such as incident power, position of the material inside the microwave cavity and the time of microwave irradiation, regression models were developed for estimating temperature rise in each of these susceptors. These models were found to newlinebe statistically significant. The results of numerical simulation led to better understanding on the susceptor characteristic