Experimental and Kinetic Modeling Study of Combustion of JP-8, its Surrogates and Components in Laminar Premixed Flows

Experimental and kinetic modeling studies are carried out to characterize premixed combustion of jet fuels, its surrogates, and reference components in laminar nonuniform flows. In previous studies, it was established that the Aachen surrogate made up of 80% n-decane and 20% trimethylbenzene by weight and surrogate C made up of 57% n-dodecane, 21% methylcyclohexane and 22% o-xylene by weight reproduces key aspects of combustion of jet fuels in laminar nonpremixed flows. Here these surrogates and a jet fuel are tested in premixed, nonuniform flows. The counterflow configuration is employed, and critical conditions of extinction are measured. In addition, the reference fuels tested are n-heptane, n-decane, n- dodecane, methylcyclohexane, trimethylbenzene, and oxylene. The measured critical conditions of extinction of the Aachen surrogate and surrogate C are found to agree well with those for jet fuel. In general the alkanes n-heptane, n-decane, and n-dodecane, and methylcyclohexane are found to be more reactive than the aromatics o-xylene and trimethylbenzene. Flame structure and critical conditions of extinction are predicted for the reference fuels and the surrogates using a semi-detailed kinetic model. The predicted values are found to agree well with experimental data. Sensitivity analysis show that the lower ractivity of the aromatic species, arises from the formation of resonantly stabilized radicals. These radicals are found to have a scavenging effect. The present study on premixed flows together with previous studies on nonpremixed flows show that the Aachen surrogate and surrogate C accurately reproduce many aspects of premixed and nonpremixed combustion of jet fuels.