A Computational Study of Plasma-Assisted Ammonia/Hydrogen Combustion Using a Phenomenological Model

Nanosecond repetitively pulsed (NRP) discharges offer promising avenues for enhancing the combustion characteristics of ammonia (NH3). However, the intricacies underlying this enhancement, particularly the optimization of plasma actuation strategies, are not fully understood. Existing zero-dimensional (0D) numerical studies, primarily concentrating on reaction kinetics, often lack experimental corroboration. This work highlights the significant uncertainties in plasma-assisted combustion (PAC) mechanisms and the cross-sectional data for NH3. A phenomenological plasma model has been developed and refined to delineate the distribution of plasma energy among three primary channels: ultrafast heating, ultrafast dissociation of O2 and NH3, and slow gas heating from vibrational energy relaxation. This model has been integrated into a reacting flow solver for the analysis of a jet-wall burner, where a laminar lean NH3/H2 flame is subjected to NRP glow discharges. The findings illustrate that plasma-induced chemical effects cause a pronounced upstream shift in the flame stabilization and intensify the NO production in this specific case.