Mathematical modeling of catalytic-surface combustion of reacting flows

Catalytic combustion of methane-air 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. Readsorption of some produced gases is also possible. The present paper is concerned with the numerical computation of heat transfer and chemical reactions in flowing methane-air mixtures impinging vertically on a platinum-coated hot plate. Seventy-three elementary reactions are included in the gas phase and in the solid platinum surface. The platinum surface temperature is fixed, whereas the properties of the reacting flow are computed. Finite-volume equations are solved iteratively for the reacting gas flow properties. In the platinum surface, surface species balance equations under steady-state conditions are solved numerically. The agreement with existing numerical data is fairly good for all main combustion products, whereas differences are observed for the rare species such as CO, O, H, HO2, and CH2O. The accuracy of the present results is accessed by checking the balance of the carbon element in the present carbon-containing compounds and similar published numerical data. The computational results for chemical reactions and mass transfer at the gas-surface interface are correlated by nondimensional relations.