Study of ignition delay time of methane based on a rapid compression machine

In order to investigate the combustion characteristics of methane (CH₄), effects of the driving gas pressure, initial pressure and equivalence ratio on the ignition delay time of CH₄/O₂/Ar mixture were investigated using a rapid compression machine (RCM) at initial temperature 288K, driving gas pressure of 0.25-0.65 MPa, initial pressure of 0.06-0.10 MPa and equivalence ratio of 0.57-1.33 in this study. Kinetics model was built to simulate effects of the compressed temperature on the ignition delay time of CH₄/O₂/Ar mixture and to simulate the combustion process with the same initial pressure and equivalence ratio as experiments. The results show that the ignition delay time of CH₄/O₂/Ar mixture has a mild fluctuation within a narrow range under a certain range of driving gas pressure. The ignition delay time slightly extends under a high driving gas pressure. However, it has a significant increase when the driving gas pressure is extremely low. The ignition delay time of CH₄/O₂/Ar mixture shortens with increasing compressed temperature. With increasing initial pressure, the ignition delay time of CH₄/O₂/Ar mixture shortens under different equivalence ratios, with increasing equivalence ratio, and the ignition delay time of CH₄/O₂/Ar mixture extends under different initial pressures.