The Effect of Exhaust Gas Recirculation (EGR) on Fundamental Characteristics of Premixed Methane/Air Flames 2020-01-0339
Increasingly stringent regulations of internal combustion engines emissions have increased focus on alternative fuels for transportation and emission reduction techniques, such as exhaust gas recirculation (EGR). Natural gas is a promising alternative to conventional petroleum derived automotive fuels since it provides lower exhaust emissions, higher octane ratings, and better fuel economy. Although many studies have investigated fundamental combustion characteristics of methane/air flames diluted with either CO2, N2 or H2O in order to investigate the EGR effect, studies analyzing actual EGR content (CO2+N2+H2O) are very rare. In the present study, spherically expanding flames were employed to investigate the EGR effect on laminar flame speeds and burned gas Markstein lengths of premixed methane/air mixtures at 3 bar and 373 K through both experiments and numerical simulations. The EGR content was simulated with a mixture of 9.50 % CO2 + 71.49 % N2 + 19.01 % H2O and the EGR ratio was varied from 0% to 15%. Numerical results were obtained from CHEMKIN using the GRI-Mech 3.0, USC Mech II, and San Diego mechanisms. Numerical laminar flame speed results were compared with experimental findings to evaluate the performances of these mechanisms for methane/air flames at high temperature, high pressure and high dilution ratios.
Berk Can Duva, Yen-Cheng Wang, Lauren Chance, Elisa Toulson