The Function of Hydrogen Chloride on Methane-Air Premixed Flame

Numerical simulations were performed at atmospheric pressure in order to understand the effect of additives on flame speed, flame temperature, radical concentrations, NOx formation, and heat flux in freely propagating CH4-Air flames. The additives were both carbon dioxide and hydrogen chloride which had a combination of physical and chemical behavior on hydrocarbon flame. In the flame established with the same mole of methane and additive, hydrogen chloride significantly contributed toward the reduction of flame speed, flame temperature, NOx formation and heat flux by the chemical effect, whereas carbon dioxide mainly did so by the physical effect. The impact of hydrogen chloride on the decrease of the radical concentration was about 1.4 similar to 3.0 times as large as that of carbon dioxide. Hydrogen chloride had higher effect on the reduction of EINO than carbon dioxide because of the chemical effect of hydrogen chloride. The reaction, OH+HCl -> Cl+H2O, played an important role in the heat flux from flames added by hydrogen chloride instead of the reaction, OH+H-2 -> H+H2O which was an important reaction in hydrocarbon flames.