Gliding arc-assisted methane/ammonia premixed combustion and NOx emission characteristics
MENG Xu
FANG Shidong
LIANG Jike
LI Keke
CHU Jianjun
CHAO Yu
SHEN Jie
CHEN Mian
XIANG Kaixin
Abstract：The challenges of inadequate combustion stability and excessive NO*emissions remain critical bottlenecks for the utilization of ammonia as a zero-carbon fuel.Gliding arc plasma technology is employed to enhance the combustion performance of methane/ammonia premixed mixtures.The stability and emission characteristics of methane/ammonia/air premixed swirling flames are examined under various equivalence ratios(Φ)and ammonia contents(xNH,).Increasing ammonia contents raises the flame height and reduces flame stability,whereas the application of gliding arc plasma significantly improves stability.With xNH,ranging from 0 to 1.0,the use of gliding arc plasma extends the lean blow-off limit to 0.46-0.79(an increase of approximately 10.2％-40.3％)and the rich blow-off limit to 1.92-2.31(an increase of approximately 28％-32％).Spectral diagnostic indicate that the emission intensities of H*,OH*and NH*active species increase with ammonia content,promoting combustion.The NH2* species play a major role in reducing NOx emissions during combustion.At Φ=1.1 and low ammonia contents(xNH,＜0.6),gliding arc plasma slight increases NO emissions,reaching a peak at xNH3=0.4(an increase of about 9％)due to the elevated flame temperature and enhanced thermal NOx formation.As xNH3 increases further,gliding arc plasma strengthens the NH2*-induced NO reaction pathways,achieving a maximum NO reduction of 15.5％.Reaction pathway analysis shows that ammonia is first converted to NH*,which subsequently participates in two competing processes:oxidation through the HNO intermediate to produce NO,or direct NO reduction to form N2 and NNH.The negative sensitivity coefficient of NO confirms that NH*plays dominant role in NO reduction.Gliding arc plasma effectively enhances the stability of methane/ammonia premixed flames,extends the lean and rich flammability limits,and reduces NOx emissions,providing a promising route for clean and efficient ammonia combustion.
Keywords：gliding arc plasmamethane/ammonia premixed combustionblow-off limitNOx emission characteristicsflame morphologyreaction pathway
Publication Date：2025-11-30
Online Publishing Date：2025-12-24(First online date of this platform, not the publication date of the document)
Pages：10( 148-157 )