Drying of moisture packed beds due to microwave heating using a rectangular waveguide

2002 ◽  
Author(s):  
Kazuo Aoki ◽  
Phadungsak Ratanadecho ◽  
Takashi Mikawa ◽  
Masatoshi Akahori
Keyword(s):  
Microwave Heating ◽  
Rectangular Waveguide ◽  
Packed Beds

The Effect of Surface Structure on Microwave Heating

2010 ◽  
Author(s):  
Masatoshi Akahori ◽  
Kazuo Aoki ◽  
Shinya Taniguchi
Keyword(s):  
Surface Structure ◽  
Microwave Heating ◽  
Rectangular Waveguide ◽  
High Performance ◽  
Heating Efficiency ◽  
Transmitted Waves ◽  
The Relationship ◽  
Effect Of Surface

In microwave heating, interference of transmission wave and reflection wave in a sample has an important meaning. We focus on the high performance of the heating efficiency due to changing the surface structure of the sample. Using the microwave of TE10 mode and frequency of 2.45GHz in rectangular waveguide, we have investigated the effect of the surface structure of the material on the characteristics of microwave heating, and have indicated the guideline for the optimization of microwave heating by controlling reflected and transmitted waves. It was found that the rectangle surface structure was effective for the high performance of the heating efficiency, by considering the relationship between the mode and the surface structure.

Interactions Between Electromagnetic and Thermal Fields in Microwave Heating of Hardened Type I-Cement Paste Using a Rectangular Waveguide (Influence of Frequency and Sample Size)

2009 ◽  
Vol 131 (8) ◽  
Author(s):  
P. Rattanadecho ◽  
N. Suwannapum ◽  
W. Cha-um
Keyword(s):  
Microwave Heating ◽  
Cement Paste ◽  
Power Distribution ◽  
Rectangular Waveguide ◽  
Three Dimensional ◽  
Heating Time ◽  
Detailed Knowledge ◽  
Type I ◽  
Two Dimensional ◽  
Materials Research

Microwave heating-drying of hardened Type I-cement paste using a rectangular waveguide is a relatively new area of cement-based materials research. In order to gain insight into the phenomena that occur within the waveguide together with the temperature distribution in the heated cement paste samples, a detailed knowledge of absorbed power distribution is necessary. In the present paper, a three-dimensional finite difference time domain scheme is used to determine electromagnetic fields (TE10-mode) and microwave power absorbed by solving transient Maxwell’s equations. Two-dimensional heat transport within the cement paste located in rectangular waveguide is used to evaluate the variations of temperature with heating time at different frequencies and sample sizes. A two-dimensional heating model is then validated against experimental results and subsequently used as a tool for efficient computational prototyping.

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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