Exploring gasoline oxidation chemistry in jet stirred reactors
Résumé
Recent decades have seen increasingly restrictive regulations applied to gasoline engines. Gasoline combustion
chemistry must be investigated to achieve a better understanding and control of internal combustion engine
efficiency and emissions. In this work, several gasoline fuels, namely the FACE (Fuel for Advanced Combustion
Engines) gasolines, were selected as targets for oxidation study in jet-stirred reactors (JSR). The study is facilitated
by formulating various gasoline surrogate mixtures with known hydrocarbon compositions to represent
the real gasolines. Surrogates included binary mixtures of n-heptane and iso-octane, as well as more complex
multi-component mixtures. The oxidation characteristics of FACE gasolines and their surrogates were experimentally
examined in JSR-1 and numerically simulated under the following conditions: pressure 1 bar, temperature
500–1050 K, residence time 1.0 and 2.0 s, and two equivalence ratios (ϕ=0.5 and 1.0). In the high
temperature region, all real fuels and surrogates showed similar oxidation behavior, but in the low temperature
region, a fuel’s octane number and composition had a significant effect on its JSR oxidation characteristics. Low
octane number fuels displayed more low temperature reactivity, while fuels with similar octane number but a
larger number of n-alkane components were more reactive. A gasoline surrogate kinetic model was examined
with FACE gasoline experiments either measured in JSR-2, or taken from previous work under the following
conditions: pressure 10 bar, temperature 530–1200 K, residence time 0.7 s, and three equivalence ratios
(ϕ=0.5, 1.0 and 2.0). Comparison between FACE gasoline experimental results with surrogate model predictions
showed good agreement, demonstrating considerable potential for surrogate fuel kinetic modeling in engine
simulations.