Comparative performance of various susceptor materials and vertical cavity shapes for selective microwave hybrid heating (SMHH)

Abstract

The microwave processing of materials is gaining popularity over the past decade due to its unique heating abilities. The microwave hybrid heating (MHH) technique has effectively processed bulk metallic materials. MHH is assisted by susceptor material which forces metals to absorb microwave radiations. Further, MHH is modified to selective microwave hybrid heating (SMHH) to increase the efficiency of the process. This work examines the performance of Graphite and Charcoal susceptors with a conical vertical cavity for SMHH using FEM simulation. It is observed that the maximum temperature achieved by Graphite was 215 ℃ at an exposure time of 300 s, whereas, for Charcoal susceptor, it is 655 ℃. Further, the effect of different vertical cavity shapes (cylindrical and conical) on the SMHH technique is presented for Charcoal susceptor. For an exposure time of 300 s, the temperature rise in the conical and cylindrical cavity is 655 ℃ and 319 ℃, respectively. From resistive heat flow, time-temperature profile and temperature distribution, it is clear how SMHH is significantly effective for a conical vertical cavity having Charcoal susceptor. In addition, the performance of the conical vertical cavity having Charcoal susceptor was validated through experimental study. The real-time temperature profile was determined through testo 885/ testo 890 thermal imaging camera. The observed maximum temperature of the susceptor after heating for 300 s was 639.9 ℃.