Catalytic combustion of hydrocarbon mixtures involves the adsorption of the fuel and oxidant into a platinum surface, chemical reactions of the adsorbed species, and the desorption of the resulting products. Re-adsorption of some produced gases is also possible. The catalytic reactions can be beneficial in porous burners that use low equivalence ratios. In this case, the porous burner flame can be stabilized at low temperatures to prevent any substantial gas emissions, such as nitric oxide. The present paper is concerned with the numerical computation of heat transfer and chemical reactions in flowing methane-air mixtures over a platinum coated hot plate. Chemical reactions are included in the gas phase and in the solid platinum surface. In the gas phase, 16 species are involved in 49 elementary reactions. On the platinum hot surface, additional surface species are included that are involved in 24 additional surface chemical reactions. The platinum surface temperature is fixed, while the properties of the reacting flow are computed. The flow configuration investigated here is the parallel boundary layer reacting flow. Finite-volume equations are obtained by formal integration over control volumes surrounding each grid node. Up-wind differencing is used to ensure that the influence coefficients are always positive to reflect the physical effect of neighboring nodes on a typical central node. The finite-volume equations are solved iteratively for the reacting gas flow properties. On the platinum surface, surface species balance equations, under steady-state conditions, are solved numerically by an under-relaxed linear algorithm. A non-uniform computational grid is used, concentrating most of the nodes near the catalytic surface. Surface temperatures, 1150 K and 1300 K, caused fast reactions on the catalytic surface, with very slow chemical reactions in the flowing gas. These slow reactions produce mainly intermediate hydrocarbons and unstable species. The computational results for the chemical reaction boundary layer thickness and mass transfer at the gas-surface interface are correlated by non-dimensional relations, taking the Reynolds number as the independent variable. Chemical kinetic relations for the reaction rate are obtained which are dependent on reactants’ concentrations and surface temperature.

1.
Williams
,
W. R.
,
Stenzel
,
M. T.
,
Song
,
X.
, and
Schmidt
,
L. D.
, 1991, “
Bifurcation Behavior in Homogeneous-Heterogeneous Combustion: I. Experimental Results Over Platinum
,”
Combust. Flame
0010-2180,
84
, pp.
277
291
.
2.
Song
,
X.
,
Williams
,
W. R.
,
Schmidt
,
L. D.
, and
Aris
,
R.
, 1991, “
Bifurcation Behavior in Homogeneous-Heterogeneous Combustion: II. Computations for Stagnation-Point Flow
,”
Combust. Flame
0010-2180,
84
, pp.
292
311
.
3.
Warnatz
,
J.
,
Allendorf
,
M. D.
,
Kee
,
R. J.
, and
Coltrin
,
M. E.
, 1994, “
A Model of Elementary Chemistry and Fluid Mechanics in the Combustion of Hydrogen on Platinum Surfaces
,”
Combust. Flame
0010-2180,
96
, pp.
393
406
.
4.
Deutschmann
,
O.
,
Behrendt
,
F.
, and
Warnatz
,
J.
, 1994, “
Modeling and Simulation of Heterogeneous Oxidation of Methane on a Platinum Foil
,”
Catal. Today
0920-5861,
21
, pp.
461
470
.
5.
Raja
,
L. L.
,
Kee
,
R. J.
,
Deutschmann
,
O.
,
Warnatz
,
J.
, and
Schmidt
,
L. D.
, 2000, “
Critical Evaluation of Navier-Stokes, Boundary-Layer, and Plug-Flow Models of the Flow and Chemistry in a Catalytic-Combustion Monolith
,”
Catal. Today
0920-5861,
59
, pp.
47
60
.
6.
Coltrin
,
M. E.
,
Kee
,
R. J.
, and
Rupley
,
F. M.
, 1991, “
Surface Chemkin: A General Formalism and Software for Analyzing Heterogeneous Chemical Kinetics at a Gas-Surface Interface
,”
Int. J. Chem. Kinet.
0538-8066,
23
, pp.
1111
1128
.
7.
Abou-Ellail
,
M. M.
,
Gosman
,
A. D.
,
Lockwood
,
F. C.
, and
Megahed
,
I. E. A.
, 1978, “
Description and Validation of a Three-Dimensional Procedure for Combustion Chamber Flows
,”
AIAA J.
0001-1452,
2
, pp.
71
80
;
Abou-Ellail
,
M. M.
,
Gosman
,
A. D.
,
Lockwood
,
F. C.
, and
Megahed
,
I. E. A.
,also, published in
Turbulent Combustion
,
L.
Kennedy
, ed.,
Progress in Aeronautics and Astronautics
,
AIAA
,
New York
, 1978, Vol.
58
, pp.
163
190
.
8.
Tong
,
T. W.
,
Abou-Ellail
,
M. M.
,
Li
,
Y.
, and
Beshay
,
K. R
, 2004, “
Numerical Computation of Reacting Flow in Porous Burners With an Extended CH4–Air Reaction Mechanism
,” ASME Paper No. HT-FED 2004-56012.
9.
Deutschmann
,
O.
,
Maier
,
L. I.
,
Riedel
,
U.
,
Stroemman
,
A. H.
, and
Dibble
,
R. W.
, 2000, “
Hydrogen Assisted Catalytic Combustion of Methane on Platinum
,”
Catal. Today
0920-5861,
59
, pp.
141
150
.
10.
Tong
,
T.
,
Abou-Ellail
,
M.
, and
Li
,
Y.
, 2006, “
Mathematical Modeling of Catalytic-Surface Combustion of Reacting Flows
,” accepted for publication at AIAA Journal of Thermophysics and Heat Transfer;
Tong
,
T.
,
Abou-Ellail
,
M.
, and
Li
,
Y.
,presented at 9th AIAA/ASME Joint Thermophysics & Heat Transfer Conference, San Francisco, CA, AIAA Paper 2006-3815.
11.
Schlichting
,
H.
, 1979,
Boundary-Layer Theory
,
McGraw-Hill Book Company
, New York, Chap. 7.
You do not currently have access to this content.