The applicability and usefulness of combustion in porous media is of much interest due to its competitive combustion efficiency and lower pollutants formation. In the previous works, the focus has been on the effects of combustion and heat transfer parameters such as excess air ratio, thermal power, solid conductivity, convective heat transfer coefficient, and radiation properties on centerline temperature and pollutant formations. A premixed combustion scheme and a fixed porous medium with constant geometrical parameters have been used in these works; therefore, the effects of porous material parameters have been less considered. In this research, the effects of geometrical parameters of porous medium, namely porosity and permeability, on centerline temperature distributions, peak flame temperature, flame structure, and gas mixture preheating have been investigated by numerical methods. To this, a two-dimensional axis-symmetric physical model of porous burner is considered. As the most typical porous burners, a two stage one which has preheating porous zone (PPZ) and combustion porous zone (CPZ) is studied. The continuity, momentum, energy, turbulence, and species transport equations are solved employing a one-step chemical reaction mechanism with an eddy-dissipation model for rate of reactions. The turbulence is modeled with two transport equations which are not considered in similar works. The combustion regime is assumed to be diffusion and combustion parameters are fixed in all cases. Porosity effects on the structure and temperature characteristic of the flame are probed in a wide range for PPZ and CPZ. Critical permeability is defined and permeability effects on flame characters in both of the preheating and combustion regions are studied thoroughly.

1.
Hsu
,
P. F.
,
Evans
,
W. D.
, and
Howell
,
J. R.
, 1993, “
Experimental and Numerical Study of Premixed Combustion within Nonhomogenous Porous Ceramics
,”
Combust. Sci. Technol.
0010-2202,
90
, pp.
149
172
.
2.
Khanna
,
V.
,
Goel
,
R.
, and
Ellzey
,
J. L.
, 1995, “
Measurements of Emissions and Radiation for Methane Combustion Within a Porous Medium Burner
,”
Combust. Sci. Technol.
0010-2202,
99
, pp.
133
142
.
3.
Ellzey
,
J. L.
, and
Goel
,
R.
, 1995, “
Emissions of CO and NO from a Two Stage Porous Media Burner
,”
Combust. Sci. Technol.
0010-2202,
107
, pp.
81
91
.
4.
Tseng
,
C. J.
, and
Howell
,
J. R.
, 1996, “
Combustion of Liquid Fuels in a Porous Radiant Burner
,”
Combust. Sci. Technol.
0010-2202,
112
, pp.
141
161
.
5.
Trimis
,
D.
, and
Durst
,
F.
, 1996, “
Combustion in a Porous Medium, Advances and Applications
,”
Combust. Sci. Technol.
0010-2202,
121
, pp.
153
168
.
6.
Zhou
,
X. Y.
, and
Pereira
,
J. C. F.
, 1997, “
Numerical Study of Combustion and Pollutants Formation in Inert Non Homogeneous Porous Media
,”
Combust. Sci. Technol.
0010-2202,
130
, pp.
335
364
.
7.
Malico
,
I.
,
Zhou
,
X. Y.
, and
Pereira
,
J. C. F.
, 2000, “
Two-Dimensional Numerical Study of Combustion and Pollutants Formation in Porous Burners
,”
Combust. Sci. Technol.
0010-2202,
152
, pp.
57
79
.
8.
Magnussen
,
B. F.
, and
Hjertager
,
B. H.
, 1976, “
On Mathematical Models of Turbulent Combustion With Special Emphasis on Soot Formation and Combustion
,”
Proceedings 16th Symposium International on Combustion
,
The Combustion Institute
.
9.
Bejan
,
A.
, and
Nield
,
R.
, 1998,
Convection in Porous Media
,
2nd ed.
,
Springler
,
Berlin
.
10.
Launder
,
B. E.
, and
Spalding
,
D. B.
, 1972,
Lectures in Mathematical Models of Turbulence
,
Academic
,
London, England
.
11.
FLUENT 6.0 Documents, 2001.
12.
Lyamin
,
G. A.
, and
Pinaev
,
A. V.
, 1986, “
Combustion Regimes in an Inert Porous Material
,”
Combust., Explos. Shock Waves
0010-5082,
22
(
5
), pp.
553
558
.
You do not currently have access to this content.