Lund University Study on Ammonia/n-Heptane Combustion in Marine Engine Conditions

Researchers from Lund Universityconducted a detailed study of ammonia/n-heptane combustion under marine engineconditions using direct numerical simulation (DNS) to understand ignition,combustion modes, and emission formation in ammonia engines. The DNS considereda temporally evolving jet with two regions: a fuel-lean premixed ammonia/airmixture and a fuel-rich n-heptane jet/ammonia/air mixing zone, representingtypical marine engine conditions.

Results revealed multiple reactionlayers: fuel-lean premixed flame (LPF), fuel-rich premixed flame (RPF),diffusion flame (DF), and rich ammonia oxidation layer (RAOL). The LPFpropagates into the ammonia/air mixture, strongly affecting combustionefficiency and NO formation, while the RPF develops in the fuel-rich mixturedue to low-temperature ignition. The DF oxidizes intermediates and NO, whereasthe RAOL promotes ammonia oxidation, forming hydrogen, amino radicals, andother intermediate species that participate in DF and RPF reactions.

More details can be found in the paperpublished in Combustion and Flame: https://www.sciencedirect.com/science/article/pii/S001021802500389X

Understanding these mechanisms offersinsights into optimizing ammonia combustion for lower emissions and improvedefficiency in ammonia-fueled marine engines, supporting cleaner combustiondesign and advancing Hi-EFECTS research on alternative marine fuels.