Physics of Fluids, Journal Year: 2024, Volume and Issue: 36(11)

Published: Nov. 1, 2024

Ammonia has emerged as a promising carbon-free fuel for mitigating greenhouse gas emissions. However, its application in practical combustion systems is limited by several issues including low heating value and slow flame propagation speed, which have posed challenges maintaining stable combustion. As an attempt to resolve these issues, we numerically investigated premixed ammonia–air using detailed chemical mechanism heat-recirculating, Swiss-roll burner that was proposed based on the concept of “excess-enthalpy.” The main focus put stabilizations well characteristics NO/N2O emissions across wide range operational conditions. results showed use led significantly broadened stability regime pure ammonia combustion, could be attributed effective preheating from products unburnt mixture. relationship between dimensionless heat transfer parameter excess-enthalpy quantified linear correlation revealed. In addition, flow expansion recirculation within chamber generation vortices, also beneficial stabilizations. NO at outlet were witnessed growth laminar region, gentler increase flow-transition stage, final leveling off turbulent condition with Reynolds number. For given number, emission non-monotonic variation equivalence ratios, relatively levels either fuel-lean or fuel-rich another major concern, N2O found more significant region conditions, both should avoided operations.

Language: Английский