Chemical kinetic and behavior study of the cracked gas of H2/N2 and DME addition on ammonia combustion in lean-burn condition

Abstract

The comparisons between the cracked gas and DME addition with a certain proportion on combustion behaviors are studied. A mechanism for the prediction of ammonia/H2/DME is updated based on the previously developed one. Since it is important to use a simplified mechanism in 3D numerical simulations, mechanism simplification is conducted, resulting in one with 72 species and 459 reactions. The premixed laminar flame simulations indicate that both the fuel cracking with hydrogen production and DME addition with a small amount can enhance laminar burning velocity (LBV) and extend lean-burn limit. NO is increased with hydrogen or DME addition due to the chemical and thermal effects, and comparatively, adding cracked gas leads to lower NO generation for the same blending ratio. The 3D simulated results shows that a sudden increase of HNO for DME addition during the combustion induces a higher NO formation relatively to that for hydrogen addition.