Laminar Combustion Characteristics of Premixed Shale Gas and Air Flames

Abstract

The laminar combustion characteristics of premixed shale gas/air flames were studied by spherical expansion flame experiments and chemical kinetics simulations. The influence of the initial temperature, the initial pressure, and the equivalent ratio on the laminar flame propagation process was analyzed. The variation of the laminar burning velocity and the flame stability with the initial conditions is discussed. The change trend of the reactants and products in the shale gas laminar flame was studied. The relationships between the important free radicals, the adiabatic flame temperature, and the laminar burning rate were analyzed. The results show that the initial temperature had little influence on the chemical reaction rate, the flame propagation process was stable, and the H+OH mole fraction peak increased, which was the main reason for the enhancement of the laminar burning velocity. When the initial pressure increased, the chemical reaction rate increased obviously, the concentration of H, O, and OH decreased, the velocity of flame propagation was slowed, and the stability of the front flame was reduced. When the equivalent ratio was 1.0, the velocity of the laminar flame was the fastest, the inhibition effect of the lean mixture on the velocity of the flame propagation was stronger than that of the concentrated mixture, and with the increase of the equivalence ratio, the front flame became stable.