Laminar Flame Speeds of Oxy-Methane Flames With CO2 Dilution at Elevated Pressures

Abstract Spherically expanding, laminar flame experiments have been conducted for oxy-methane mixtures diluted in CO2. Test conditions consisted of pressures of 5 atm and 10 atm, an ambient initial temperature of 298 K, and a full range of equivalence ratios from lean to rich. Schlieren imaging was used to image the flames. The mixtures tested in this study contained helium for the purpose of increasing the Lewis number to suppress onset of thermal-diffusive instabilities. Flame speeds ranged from 24.3 to 30.4 cm/s at 5 atm initial pressure and from 17.9 to 22.6 cm/s at 10 atm, resulting in an approximately 26% decrease in flame speed across all tested equivalence ratios as a result of the doubling in initial pressure. Predicted flame speeds from AramcoMech2.0 tended to be higher than the experimental data by 3% at 5 atm initial pressure and 8% at 10 atm initial pressure, indicating that the performance of the mechanism is quite good for this mixture, but diminishes slightly as pressure increases.

Laminar Flame Speeds of Oxy-Methane Flames With CO2 Dilution at Elevated Pressures Conference Paper