A numerical study on premixed methane/ethylene/air flames with various ethylene fractions and equivalence ratios was conducted at room temperature and atmospheric pressure. The effects of ethylene addition on laminar burning velocity

flame structure and flame stability under the condition of lean burning were investigated. The results show that the laminar burning velocity increases with ethylene fraction

especially at a large equivalence ratio. More ethylene addition gives rise to higher concentrations of H

O and OH radicals in the flame

which significantly promotes chemical reactions

and a linear correlation exists between the laminar burning velocity and the maximum H+OH concentration in the reaction zone. With the increase of ethylene fraction

the adiabatic flame temperature is raised

while the inner layer temperature becomes lower

contributing to the enhancement of combustion. Markstein length and Markstein number

representative of the flame stability

increase as more ethylene is added

indicating the tendency of flame stability to improve with ethylene addition.