Plasma-assisted pyrolysis and ignition of pre-vaporized n-heptane, iso-octane and n-decane

We intensively investigated the kinetic enhancement of dielectric-barrier-discharge (DBD) plasma on the pyrolysis and ignition of n-heptane, iso-octane, and n-decane fuels in a counterflow diffusion burner. The DBD plasma generated upstream from the fuel nozzle can contribute to low-temperature pyrolysis and high-temperature oxidation of pre-vaporized liquid fuels. Stable and short-lived intermediate species generated by plasma were measured by ex situ gas chromatography (GC) and in situ planar laser induced fluorescence (PLIF), respectively. GC results indicate that with plasma assistance approximately 2–3% of large hydrocarbons decompose at temperatures as low as 370 K and within 1 s. High-temperature oxidation experiments demonstrate that DBD can lower the ignition temperature of all three fuels with various global flow stretch rates. Experiments were compared with numerical analysis performed using the OPPDIF code that is formulated for the counterflow geometry. Finally, the discrete chemical explosive mode analysis (CEMA) elucidates the promotion of plasma-induced species, such as H₂, C₂H₄, and OH radicals.