Experimental analysis of microwave heating of dielectric materials using a rectangular wave guide (MODE: TE10) (Case study: Water layer and saturated porous medium)

2009 ◽  
Vol 33 (3) ◽  
pp. 472-481 ◽  
Author(s):  
Waraporn Cha-um ◽  
Phadungsak Rattanadecho ◽  
Watit Pakdee
Keyword(s):  
Porous Medium ◽  
Microwave Heating ◽  
Experimental Analysis ◽  
Saturated Porous Medium ◽  
Water Layer ◽  
Dielectric Materials ◽  
Wave Guide ◽  
Rectangular Wave ◽  
Guide Mode

Experimental Validation of a Combined Electromagnetic and Thermal Model for a Microwave Heating of Multi-Layered Materials Using a Rectangular Wave Guide

2002 ◽  
Vol 124 (5) ◽  
pp. 992-996 ◽  
Author(s):  
P. Rattanadecho ◽  
K. Aoki and ◽  
M. Akahori
Keyword(s):  
Microwave Heating ◽  
Dielectric Material ◽  
Dielectric Materials ◽  
Layered Materials ◽  
Wave Guide ◽  
Heating Process ◽  
Reflected Waves ◽  
Rectangular Wave ◽  
Model Combining ◽  
Heating Pattern

The heating of multi-layered materials by microwave heating with rectangular wave guide has been investigated numerically and experimentally. The multi-layered materials, which consist of the layer of higher dielectric material (antireflection layer) and lower dielectric material (sample), have the convergent effect of the incident microwave in sample, and it can change the heating pattern in the sample with ease. In this study, the effect of an antireflection layer thickness on the heating process is clarified in detail, considering the interference between incidents and reflected waves in the dielectric materials. Based on a model combining the Maxwell and heat transport equations, the results showed that when a layer of lower dielectric material is attached in front of sample, the microwave energy absorbed and distribution of temperature within the sample are enhanced. The predicted results are in agreement with experimental results for microwave heating of multi-layered materials using a rectangular wave guide.

Natural Convection in a Saturated Variable-Porosity Medium Due to Microwave Heating

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Watit Pakdee ◽  
Phadungsak Rattanadecho
Keyword(s):  
Porous Medium ◽  
Microwave Heating ◽  
Maxwell’S Equations ◽  
Maxwell's Equations ◽  
Saturated Porous Medium ◽  
Simple Algorithm ◽  
Heating Process ◽  
Variable Porosity ◽  
Dimensional Variation ◽  
Difference Time

Microwave heating of a porous medium with a nonuniform porosity is numerically investigated based on a proposed numerical model. A two-dimensional variation of porosity of the medium is considered. The generalized non-Darcian model developed takes into account the presence of a solid drag and the inertial effect. The transient Maxwell’s equations are solved by using the finite difference time domain method to describe the electromagnetic field in the waveguide and medium. The temperature profile and velocity field within a medium are determined by solution of the momentum, energy, and Maxwell’s equations. The coupled nonlinear set of these equations is solved using the SIMPLE algorithm. In this work, a detailed parametric study is conducted on heat transport inside a rectangular enclosure filled with a saturated porous medium of constant or variable porosity. The numerical results agree well with the experimental data. Variations in porosity significantly affect the microwave heating process as well as the convective flow pattern driven by microwave energy.

Theoretical Analysis of Microwave Heating of Dielectric Materials Filled in a Rectangular Waveguide With Various Resonator Distances

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
Phadungsak Rattanadecho ◽  
Waraporn Klinbun
Keyword(s):  
Microwave Heating ◽  
Rectangular Waveguide ◽  
Control Volume ◽  
Saturated Porous Medium ◽  
Simple Algorithm ◽  
Dielectric Materials ◽  
Microwave Cavity ◽  
Heating Process ◽  
Finite Control ◽  
Volume Method

This paper proposes mathematical models of the microwave heating process of dielectric materials filled in a rectangular waveguide with a resonator. A microwave system supplies a monochromatic wave in a fundamental mode (TE10 mode). A convection exchange at the upper surface of the sample is considered. The effects of resonator distance and operating frequency on distributions of electromagnetic fields inside the waveguide, temperature profile, and flow pattern within the sample are investigated. The finite-difference time-domain method is used to determine the electromagnetic field distribution in a microwave cavity by solving the transient Maxwell equations. The finite control volume method based on the SIMPLE algorithm is used to predict the heat transfer and fluid flow model. Two dielectric materials, saturated porous medium and water, are chosen to display microwave heating phenomena. The simulation results agree well with the experimental data. Based on the results obtained, the inserted resonator has a strong effect on the uniformity of temperature distributions, depending on the penetration depth of microwave. The optimum distances of the resonator depend greatly on the operating frequencies.

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