Advancements in Sustainable Aviation Fuels: Impact of Nano-Additives and Ammonia-Based Strategies on Emissions

Our study investigates the impact of nanoparticulate additives-specifically those based on ammonia and water-on the combustion characteristics of Jet-A1 aviation fuel, using a 300-kW liquid swirl combustor. Experiments were conducted at two global equivalence ratios (Phi = 0.24 and Phi = 0.40), focusing on laminar flame speed (LFS) and flame properties through chemiluminescence imaging and modal analysis techniques. The primary objective was to understand how these nano-additives modulate flame dynamics and internal chemical reactions, alongside evaluating the environmental implications of combustion alterations. Results showed that integrating urea and water additives into the fuel matrix affected LFS, enhancing it at the lower equivalence ratio but having detrimental effects at the higher ratio. Modal analysis revealed a notable stabilizing influence on flame behavior, especially under leaner fuel conditions. The addition of water and urea influenced combustion chemistry and spray patterns, leading to more uniform sprays and more complete combustion. Chemiluminescence imaging demonstrated higher emission intensity of NH2* radicals compared to NH* radicals, varying with the global equivalence ratio. The data indicated a significant reduction in NOx emissions, particularly at lower equivalence ratios, accompanied by a slight increase in CO2 and CO emissions.