Ignitability of Jet A1 Oxygen Co-axial Diffusion Flames Diluted with Inert Gases

In this study, the ignitability characteristics affected by an oxygen coaxial flow diluted with inert gases (nitrogen and helium) were experimentally investigated using Jet A1 oxygen diffusion flame configurations. As the molar concentration of oxygen supplied to the coaxial flow increased, the dilution of the inert gas decreased, which drastically lowered the measured minimum ignition energy. When only oxygen gas was supplied to the coaxial flow without dilution with the inert gas, ignition was most easily observed, thereby widening the ignition range. With a constant oxygen-inert co-flow rate, the ignition suppressibility under helium dilution was superior to that under nitrogen dilution as the molar concentration of oxygen decreased.