Effect of nitrogen dioxide addition on ethane auto-ignition at different pressures and equivalence ratios: Experiments and chemical kinetic modeling

Abstract

Ignition delay times of C2H6/O2/Ar mixtures with NO2 concentration changing from 0 to 2100 ppm were measured at T = 772–980 K, φ = 0.5–2.0 and p = 15–30 bar in a rapid compression machine. In general, the results show that NO2 addition significantly promotes ethane ignition and reduces its global activation energy. And NO2 promoting effect is more remarkable at fuel-lean and low-pressure condition at given NO2 concentration. The results also demonstrate that pressure shows smaller effect on the ignition of mixtures doped with NO2 than those on neat ethane ignition. Three literature NOx models are selected to validate against the new measured data set to evaluate their performances. Finally, sensitivity and flux analyses are conducted to identify the key reaction classes controlling the ignition of C2H6-NO2 mixtures.