Oxidation of an iso-paraffinic alcohol-to-jet fuel and n-heptane mixture: An experimental and modeling study

Oxidation of alcohol to jet (ATJ)/n-heptane blends was studied over a wide range of test conditions, using single pulse shock tubes. Test conditions were designed to study the effect of pressure (4 and 50 bar), and fuel loading (similar to 100 to 1400 ppm) on the oxidation of the blends across a wide range of temperatures (800-1300 K). These effects were observed by measuring concentrations of intermediate species formed using in-line gas chromatography (GC) and GCxGC TOF-MS. Results showed that increasing the initial fuel load does not have a significant impact on the results. However, increasing the pressure shifts the mixture reactivity to a lower temperature by about 150 K and causes the fuel to be oxidized instead of decomposing pyrolytically as at lower pressures. Additional experiments for pure ATJ and pure n-heptane were performed at conditions matching the ATJ/n-heptane 50 bar experiments to analyze the differences between the pure and mixed fuels. Speciation measurements were compared against predictions from a detailed kinetic model. The ability of the kinetic model to capture the effects of varying experimental test conditions on the evolution of intermediate species is discussed, and kinetic analyses have been conducted to identify the important reaction pathways.

Automated summary

The oxidation of ATJ/n-heptane blends was studied under varying test conditions, showing that increasing fuel loading had minimal impact on the results, while increasing pressure shifted reactivity to lower temperatures and caused oxidation of the fuel. Experimental results were compared against a kinetic model to analyze the differences between pure and mixed fuels.