N-heptane/O₂/Ar low temperature kinetics with nano-second pulsed plasma discharges

Plasma assisted low temperature oxidation and pyrolysis of n-Heptane/O₂/Ar mixtures have been experimentally investigated by using steady state species sampling and time-dependent species quantification with in situ tunable diode laser absorption spectroscopy (TDLAS). The present study aims to understand the effect of energy transfer via excited species and direct electron impact dissociation by varying argon and oxygen concentrations on the intermediate species and product of n-heptane oxidation in a nanosecond repetitively pulsed dielectric barrier discharge. The results show that fuel consumption and product formation increased linearly with increasing plasma pulse frequency, suggesting a lack of explosive chain-branching processes at room temperature. It is shown that pyrolysis pathways favored larger hydrocarbons with less temperature release than oxygenated pathways, where large concentrations of formaldehyde, carbon dioxide and water allowed for greater heat release.