Mathematical Modeling of Single Phase Flow and Particulate Flow Subjected to Microwave Heating

Abstract

The purpose of this research is to numerically investigate heat transfer in liquids and liquids with carried solid particles as they flow continuously in a duct that is subjected to microwave irradiation. During this process, liquid flows in an applicator tube. When flow passes through the microwave cavity, the liquid absorbs microwave power and its temperature quickly increases. The spatial variation of the electromagnetic energy and temperature fields in the liquid was obtained by solving coupled momentum, energy and Maxwell's equations. A finite difference time domain method (FDTD) is used to solve Maxwell's equations simulating the electromagnetic field. The effects of dielectric properties of the liquid, the applicator diameter and its location, as well as the geometry of the microwave cavity on the heating process are analyzed. For modeling particulate flow subjected to microwave heating, the hydrodynamic interaction between the solid particle and the carrier fluid is simulated by the force-coupling method (FCM). The Lagrangian approach is utilized for tracking particles. The electromagnetic power absorption, temperature distribution inside both the liquid and the particles are taken into account. The effects of dielectric properties and the inlet position of the particle on electromagnetic energy and temperature distributions inside the particle are studied. The effect of the particle on power absorption in the carrier liquid is analyzed. The effect of the time interval between consecutive injections of two groups of particles on power absorption in particles is analyzed as well.