Laminar flame speeds and extinction limits of preheated n-decane/O2/N2 and n-dodecane/O2/N2 mixtures

Laminar flame speeds of n-decane/air and n-dodecane/air mixtures are measured using the counterflow twin-flame configuration at preheat temperatures ranging from 360 to 470 K and equivalence ratios ranging from 0.7 to 1.4. Extinction stretch rate measurement as a function of equivalence ratio is also carried out for fuel/O2/N2 mixtures with [N2/(O2 + N2)] = 0.84 by mole and preheat temperature of 400 K. All experiments are conducted under atmospheric pressure conditions. In addition, the overall activation energies of n-decane/air mixtures at varying equivalence ratios are deduced. The experimental data for laminar flame speeds and extinction stretch rates are also simulated using chemical kinetic mechanisms available in the literature. Comparison of the experimental and computed results demonstrates the deficiencies of the existing mechanisms. Although sensitivity analysis is performed to identify the most sensitive reactions pertinent to laminar flame speed and extinction limit, the results are unable to assess the adequacy of the chemistry involving large hydrocarbons.