A numerical and experimental investigation of the modeling of microwave heating for liquid layers using a rectangular wave guide (effects of natural convection and dielectric properties)

Abstract The heating of a liquid layer by microwave with a rectangular wave guide has been investigated numerically and experimentally. It was performed for two different liquid layers: water layer and NaCl-water solution layer. A complete mathematical model is proposed, which uses comprehensive two-dimensional heat and momentum equations to describe unsteady temperature and fluid flow fields, coupled with a complete solution of the unsteady Maxwell's equations in the time domain can be used to investigate many aspects of the heating process. In this work, the effects of electric conductivity (which corresponds to the percentage by weight of NaCl in liquid layer) and microwave power level on the heating process were examined. Based on a model combining the Maxwell and heat transport and fluid flow equations, the results show that the heating kinetic strongly depends on the dielectric properties.