0
Research Papers: Natural and Mixed Convection

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

[+] Author and Article Information
Watit Pakdee1

Department of Mechanical Engineering, Research Center of Microwave Utilization in Engineering (RCME), Thammasat University, Klong Luang, Pathumthani, Thailandpwatit@engr.tu.ac.th

Phadungsak Rattanadecho

Department of Mechanical Engineering, Research Center of Microwave Utilization in Engineering (RCME), Thammasat University, Klong Luang, Pathumthani, Thailand

1

Corresponding author.

J. Heat Transfer 133(6), 062502 (Mar 08, 2011) (8 pages) doi:10.1115/1.4003535 History: Received May 11, 2010; Revised January 14, 2011; Published March 08, 2011; Online March 08, 2011

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.

FIGURES IN THIS ARTICLE
<>
Copyright © 2011 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

The microwave heating system with a rectangular waveguide

Grahic Jump Location
Figure 2

Locations of temperature measurement in the symmetrical xz plane

Grahic Jump Location
Figure 3

Schematic of the physical problem

Grahic Jump Location
Figure 4

Porosity distributions with the bead diameters: (a) 1 mm and (b) 3 mm

Grahic Jump Location
Figure 5

The temperature distributions taken at 30 s are shown to compare the numerical solutions with the experimental result

Grahic Jump Location
Figure 6

The temperature distributions taken at 50 s are shown to compare the numerical solutions with the experimental result

Grahic Jump Location
Figure 7

Time evolutions of temperature contour (°C) within the porous bed at 20 s, 40 s, and 60 s for uniform case ((a)–(c)) and nonuniform case ((d)–(f))

Grahic Jump Location
Figure 8

Centerline temperature along the z axis for uniform (dashed line) and nonuniform (solid line) porous packed beds

Grahic Jump Location
Figure 9

Velocity vectors from the two cases of porous medium: (a) nonuniform and (b) uniform

Grahic Jump Location
Figure 10

Variations of velocity magnitudes along the x axis for uniform (dashed line) and nonuniform (solid line) porous packed beds

Grahic Jump Location
Figure 11

Variations of u-component velocity along the x axis for uniform (dashed line) and nonuniform (solid line) porous packed beds

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In