Numerical and experimental study on heat transfer process under microwave irradiation using reflector to enhance energy absorption rate

Abstract

With the energy saving concerns, microwave heating method becomes much attention in heating process of various applications. Depending on applicator geometry design, type of work load, and position in a microwave heating system, it can save energy 20% to 40% more than the energy consumed by a conventional heating method. However, it is difficult to achieve this energy saving for low dielectric constant workload that cannot perform as a self-dielectric resonator (DR) load. This paper aspires to propose a new method of inserting reflector into the low dielectric constant load to enhance energy absorption rate under the microwave irradiation process. The spatial electromagnetic fields (E-field and H-field) patterns of this workload and applicator were simulated with the commercial HFSS software. By using the Poynting vector theorem, the dissipation power intensity can be calculated from the electromagnetic field and it is integrated to the second order heat transfer equation. The numerical temperature distribution result was resemblance with the experimental result. From both numerical and experimental results, the energy absorption rate of workload can be improved obviously by using a reflector as compared to the rate without using the reflector for low dielectric constant. Copyright © 2008 by ASME.