Experimental and computational investigation of autoignition of jet fuels and surrogates in nonpremixed flows at elevated pressures

Experimental and computational investigation is carried out to elucidate the mechanism of autoignition of Jet Fuels and Surrogates in nonpremixed flows at elevated pressures up to 6 bar. The counterflow configuration is employed. In this configuration a axisymmetric flow of a gaseous oxidizer stream is directed over the surface of an evaporating pool of a liquid fuel. The oxidizer stream is a mixture of oxygen and nitrogen. The jet fuels tested are JP5, JetA, and JP8, and the surrogates tested are the Aachen surrogate, consisting of 80% n-decane and 20% 1,3,5-trimethylbenzene by mass, Surrogate C made up of 60% dodecane, 20% methylcyclohexane, and 20% o-xylene by volume, and the Princeton Surrogate made up of 49.6% n-dodecane, 24.3% iso-octane, 19.8% n-propylbenzene, and 6.3% 1,3,5- trimethylbenzene by mass. The experiments are conducted at a fixed value of mass fraction of oxygen and at a fixed low value of the strain rate. The temperature of the oxidizer stream at autoignition, Tig, is measured as a function of pressure, p. Computations were carried out using a detailed mechanism and critical conditions of autoignition for surrogates were predicted and compared with measurements.