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

• Published in: International journal of thermal sciences 2013-09, Vol.71, p.118-127
• Main Authors: Yousefi, T., Mousavi, S.A., Saghir, M.Z., Farahbakhsh, B.
• Format: Article
• Language: English
• Subjects: ANSYS Multiphysics; Continuous flow; Cross-disciplinary physics: materials science; rheology; Dielectric properties; Exact sciences and technology; Materials science; Microwave heating; Other heat and thermomechanical treatments; Physics; Radiation treatments; Treatment of materials and its effects on microstructure and properties
• ISSN: 1290-0729; 1778-4166
• DOI: 10.1016/j.ijthermalsci.2013.04.006

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. •An increase in the inlet velocity leads to a drop in average outlet temperature.•As the applicator diameter was raised up to a critical diameter, heat absorption increased moderately and then dropped sharply.•An increase in applicator height results in a decrease in the absorption of heat.