Ignition of liquid jet fuel blends have been studied here for non-premixed flows using test fuels with a variety of chemical and physical properties. Prevaporized fuel experiments were conducted to understand the influence of chemical fuel differences on ignition performance with a commercial igniter in a stratified facility that allowed for control of the inflow properties and the transit time of the spark kernel to the flammable mixture. Simulations with a reduced-order reactor model were performed for conditions analogous to the premixed experiments of two base fuels and their blends. Liquid fuel spray was also introduced to the facility in a air co-flow to observe the influence of atomization and evaporation of the test fuels on the ignition performance. The fuels and their blends showed monotonic behavior, though the performance was non-linear with the changing blending fraction. Blending may have constructive or destructive chemical effects on the base fuel. Likewise, simulations showed non-linear behavior with the blending fractions of the fuels, marked by the changing minimum equivalence ratio required to observe successful ignition for different fuel blends. According to the chemical mechanism, small amounts of Jet-A fuel may have extremely beneficial effects on ignition performance. Liquid spray experiments support prior evidence of the detrimental impact of transit times over 200 µs and improvements were observed by reducing this time and increasing inflow temperature. Ignition probabilities of liquid sprays at preheated temperatures show a change in relative ranking of the test fuels, though the performances were closer between fuels than in prevaporized experiments. Ignition success favored fuels with lower boiling point temperatures, suggesting that vaporization affects the interaction with the spark kernel and may dominate the path to ignition over chemical effects.
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