Akademik Veri Yönetim Sistemi
Fuel, cilt.414, 2026 (SCI-Expanded, Scopus)
As zero-carbon emission combustion and energy production activities accelerate today, ammonia energy is attracting attention. Ammonia serves as an important hydrogen carrier and a potential alternative fuel because it contains a large amount of hydrogen. In this study, the addition of ammonia (NH3) and hydrogen (H2) fuels to a methane (CH4) flame at different ratios was tested. The experiments were conducted at constant thermal power (5 kW) and an equivalence ratio (ϕ = 0.7). A swirl-assisted combustor was used as the burner, and the number of swirl generators (1.2) was kept constant. The aim of this study is to model a realistic transition strategy representing the transition process from natural gas-fired systems to zero-carbon systems by simultaneously mixing NH3, H2, and CH4, and to evaluate the combustion stability and emission behavior. The findings indicated that increasing the ammonia fraction led to a reduction in flame temperature. However, adding hydrogen raised the lower heating value, which in turn caused the flame temperature to rise. In this burner, when NH3 is added to pure methane, the maximum allowable NH3 fraction is limited to 30% by volume, beyond which flame blowoff occurs. In contrast, hydrogen-enriched flames can tolerate higher NH3 volumetric fractions. By increasing the H2 content in the mixture, stable combustion was achieved with mixtures containing up to 50% H2 and 50% NH3. Thus, the zero-carbon fuel target was achieved. Due to the decreasing methane content, CO emissions decreased to almost zero at 4,100 ppm. Furthermore, increasing H2 content caused an increase in NOX emissions due to thermal effects, while adding NH3 at the same hydrogen ratio offset the impact of H2 and reduced NOX emissions. However, at very high NH3 ratios, the fuel’s nitrogen atoms increased NOX emissions to 4,781 ppm. Due to the low heating value of the ammonia fuel, it acted as a diluent, reducing the thermoacoustic response of the flame. However, as ammonia addition reached high levels, the flame approached the blowoff limit and became unstable again.