The oxidation of JP-8 and its surrogates in the low and intermediate temperature regime

Although not typically considered a fuel for diesel engines, the U.S. Department of Defense (DoD) directive 4140.25 mandated the aviation fuel JP-8 to be the ‘universal’fuel for all military applications. This logistical simplification was extensively field tested and JP-8 has been successfully used in the U.S. Army’s compression ignition (CI) engines. However, wide variations in cetane index, aromatic content, naphthene content, and fuel additives were observed (JP-8’s specifications are intentionally broad to keep cost at a minimum) and the impact of these variations on CI engine operations are notwell understood. During this research, the impact of these variations on the critical autoignition behavior were addressed by the oxidation of several samples of JP-8 and Jet- A in a Pressurized Flow Reactor (PFR) Facility at elevated pressures over a range of temperatures (600 – 800 K). This provided insight into which fuel properties and theirassociated variations had the most significant impact on CI engine operation.Furthermore, due to the complexity and variability of full-boiling range fuels, such as JP-8, researchers typically develop simplified blends, called surrogates, to study the combustion processes, and ultimately develop combustion models based on their results. To further investigate the oxidation of JP-8, a 4-component surrogate was utilized which roughly matched the ‘average’ JP-8 reactivity measured in the first phase of this research. The surrogate was a mixture of 43% n-dodecane, 27% iso-cetane, 15% methylcyclohexane, and 15% α-methyl-naphthalene. Neat, binary mixtures of the components, and the full surrogate were oxidized in the PFR and stable intermediate and product species were identified and quantified using permanent gas analyzers, and gas chromatography with mass spectrometry (GC/MS). These detailed studies provided kinetic and mechanistic information in the low and intermediate temperature ranges (600 – 1000 K) and at elevated pressures. The experimental results provided profiles which will be used in future studies to develop detailed and reduced kinetic models for the ignition and oxidation of these fuels.Ph.D., Mechanical Engineering -- Drexel University, 200