Effect of the elevated initial temperature on the laminar flame speeds of oxy-methane mixtures

The effect of the elevated initial temperature on the laminar flame speeds of CH4/O2/CO2 mixtures is investigated. Firstly, the measurements of the laminar flame speeds of methane at O2/CO2 atmosphere are performed in the condition of the elevated initial temperature using a Bunsen burner. The laminar flame speeds are predicted with the GRI 3.0 mechanisms. The effect of the elevated initial temperature is discussed by the kinetic simulation. The elevated unburned gas temperature increases the adiabatic flame temperature, which accelerates the combustion reaction rates and laminar burning velocities of gas mixtures. Then, the absolute and the relative differences with the transport, radiative and chemical effects of the high CO2 content are calculated respectively. The transport and radiative effects are insignificant and the chemical effect is much larger than the transport and radiative effects. Finally, the chemical reaction process is also investigated with the sensitivity analysis and reaction pathway analysis. The elevated initial temperature changes the combustion process slightly, but accelerates the global combustion reaction rate of oxy-methane mixture.