Experimental and Modeling Study of the Oxidation Kinetics of n-Undecane and n-Dodecane in a Jet-Stirred Reactor

The kinetics of oxidation of two large n-alkanes (n-undecane and n-dodecane) was studied experimentally in a jet-stirred reactor (JSR) at high pressure (P = 10 bar), at temperatures ranging from 550 to 1150 K, at a constant residence time (tau) of 1 s, and for three equivalence ratios (phi = 0.5, 1.0, and 2.0). Chemical analyses by Fourier transform infrared (FTIR) spectrometry and gas chromatography allowed for the measurement of the mole fraction of reactants, stable intermediates (including substituted tetrahydrofurans), and final products as a function of the temperature. A similar behavior was observed for the oxidation of n-undecane, n-dodecane, and Jet A-1 in a JSR However, it was shown that the pure n-alkanes oxidized faster than Jet A-1 under cool-flame conditions and intermediately yielded more ethylene. A kinetic reaction mechanism based on previous, studies(1,2) was developed and validated by a comparison to the present experimental results. The proposed reaction mechanism consisted of 5864 reversible reactions involving 1377 species. Experimental data and simulation results obtained in the current work were compared to simulations performed with a literature model.(3) Our model was also applied successfully to the modeling of the oxidation of n-dodecane under shock-tube conditions.(4,5) Species time histories and ignition delay times representing valuable complementary tests were simulated.