Laminar flame speeds of transportation-relevant hydrocarbons and jet fuels at elevated temperatures and pressures

Abstract

Laminar flame speeds of several fuel/air mixtures were experimentally determined over equivalence ratios of ϕ=0.7–1.3, preheat temperatures of Tu=350–470K, and pressures of P=1–3atm in a high-pressure counterflow setup. Fuels investigated in this work included neat components relevant to liquid transportation fuels, such as n-decane, n-dodecane, iso-octane, toluene, n-propylbenzene, 1,2,4-trimethylbenzene, and 1,3,5-trimethylbenzene, a conventional Jet-A labeled as POSF 4658, an alternative jet fuel, S-8, labeled as POSF 4734, and a four-component Jet-A surrogate composed of n-dodecane, iso-octane, n-propylbenzene, and 1,3,5-trimethylbenzene. The experimental results were also compared with computed values obtained by using various published kinetic models for different fuels. In general, the simulated results are in fair agreement with the experimental data, considering the uncertainties in both experiments and kinetic models. Further analysis on experimental data was conducted to assess the effects of preheat temperature on laminar flame speed and pressure on mass burning flux. From the variation of mass burning flux with pressure, the overall reaction orders of various fuels were extracted. The present flame propagation data at elevated pressures for large hydrocarbons can be used in surrogate formulation and mechanism validation for liquid transportation fuels.