Ignition delay times of ethane under O2/CO2 atmosphere at different pressures by shock tube and simulation methods

Pressurized oxy-fuel combustion is a promising oxy-fuel technology owing to its high efficiency and low emission. The ignition delay times of ethane under O2/CO2 atmosphere were determined in a shock tube at different pressures, equivalence ratios, and C2H6 and CO2 concentrations. The results suggested that the ignition delay times decrease with the increasing ethane concentration at 0.8, 2.0, and 10 bar, while the effect of the fuel concentration on the ignition delay times is not sensitive to the pressure. The ignition delay times increased with the increasing equivalence ratio at 0.8 and 2.0 bar, while the effect of the equivalence ratio decreased with the increasing pressure from 0.8 to 2.0 bar. At 10 bar, the effect of the equivalence ratio on the ignition delay times further weakened at high temperatures, while the ignition delay times decreased with the increasing equivalence ratio in the low-temperature range. An updated model (OXYMECH) was developed and updated on the basis of our previous work, providing yields in good agreement with the experimental data under all conditions, while Aramco 2.0 showed poor prediction of the experimental results at 10 bar. Analysis of the sensitivity and the rate of production indicated that updating the rate constants of the reactions C2H6 + HO2 ⇔ C2H5 + H2O2, H + O2 (+M) ⇔ HO2 (+M), CH3 + HO2 ⇔ CH3O + OH, 2HO2 ⇔ H2O2 + O2, C2H4 + H (+M) ⇔ C2H5 (+M), and H + O2 ⇔ O + OH improves the performance at 10 bar.