查看更多>>摘要：Ammonia is gaining increasing attention as a green alternative fuel for achieving large-scale carbon emission reduction.Despite its potential technical prospects,the harsh ignition conditions and slow flame propagation speed of ammonia pose significant challenges to its application in engines.Non-equilibrium plasma has been identified as a promising method,but current research on plasma-enhanced ammonia combustion is limited and primarily focuses on ignition characteristics revealed by kinetic models.In this study,low-temperature and low-pressure chemistry in plasma-assisted ammonia oxidative pyrolysis is investigated by integrated studies of steady-state GC measurements and mathematical simu-lation.The detailed kinetic mechanism of NH3 decomposition in plasma-driven Ar/NH3 and Ar/NH3/O2 mixtures has been developed.The numerical model has good agreements with the experimental measurements in NH3/O2 consumption and N2/H2 generation,which demonstrates the rationality of modelling.Based on the modelling results,species density profiles,path flux and sensitivity analysis for the key plasma-produced species such as NH2.NH,H2,OH.H,O.O(1D),O2(a1Δg).O2(b1∑g+),Ar*.H-,Ar+,NH3+,O2-in the discharge and afterglow are analyzed in detail to illustrate the effectiveness of the active species on NH3 excitation and decomposition at low temperature and relatively higher E/N values.The results revealed that NH2,NH,H as well as H2 are primarily generated through the electron collision reactions e+NH3→ e+NH2+H,e+NH3 → e+NH+H2 and the excited-argon collision reaction Ar*+NH3+H → Ar+NH2+2H,which will then react with highly reactive oxidative species such as O2*,O*,O,OH,and O2 to produce stable products of NOx and H2O.NH3 → NH is found a specific pathway for NH3 consumption with plasma assistance,which further highlights the enhanced kinetic effects.
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