Fuel Mixing Effects on Propagation of Premixed Flames. I. Hydrogen + Carbon Monoxide Flames

The combustion mechanisms in premixed flames having a mixture of hydrogen and carbon monoxide as the fuel and the stoichiometric amount of air as the oxidizer were investigated by numerical simulation to elucidate the fuel-mixing effects on the burning velocity. Hydrogen and carbon monoxide have similar physical properties and their stoichiometric flames with air are known to propagate through the same type of mechanism, governed by active species diffusion. The flames of the mixed fuel hydrogen+carbon monoxide were found here to have their heat-release rate distributions changing with conformity in shape when the fuel composition is changed. The burning velocity was found to vary almost linearly with the hydrogen content in the fuel. Furthermore, the flux of chemical energy which is carried into low-temperature regions by hydrogen atoms diffusing from the flame front was also found to be roughly proportional to the burning velocity.