An investigation on the microwave heating of flowing water: A numerical study

This paper describes a numerical investigation of the effect of microwave heating on a continuous flow of water in a duct. A high frequency electromagnetic field and thermal fluid model were developed in ANSYS Multiphysics to calculate the temperature change in water flow using a 915 MHz microwave unit. It was assumed that no phase change in water occurs during the heating process and in addition the water maintains the hydrodynamically fully developed flow condition. Various factors were examined in the course of this numerical investigation; namely, the effects of inlet velocity, applicator height and applicator diameter on the temperature field. The results of the assumptions in this work have been compared with the constant dielectric properties case. Average outlet temperature decreases with inlet velocity increasing. Moreover, heat absorption drops significantly with raising the applicator diameter more than a critical value.