Environmental and second law analysis of a turbojet engine operating with different fuels

Fuels such as kerosene, diesel No. 2, and JP-4 are extensively utilized in aviation engines. This study conducts a comprehensive comparison of these fuels within the context of a turbojet engine modeled using GasTurb. While key operational parameters like Mach numbers and total pressure ratios are held constant, variations are introduced in the fuel-air equivalence ratio (ϕ) and the pressure ratio of the high-pressure compressor in the turbojet engine. The results of these analyses show that kerosene exhibits the most favorable operational range, resulting in the lowest production of nitrogen oxides (NO). Conversely, diesel fuel displays a broader operational range with higher NO production. Moreover, diesel fuel yields greater CO2-equivalent emissions during combustion due to elevated levels of both CO2 and NO emissions. On the other hand, kerosene consistently produces the lowest CO2-equivalent emissions across all scenarios. Despite kerosene exhibiting relatively lower exergy efficiency and the highest exergy destruction among the three fuels, it emerges with the lowest total and specific environmental pollution costs. By analyzing a range of parameters and incorporating environmental considerations, this study identifies kerosene as the optimal choice for minimizing emissions and mitigating the environmental impact in aviation applications. •Kerosene exhibits the most favorable operational range, resulting in the lowest production of nitrogen oxides (NO) and CO2-equivalent emissions compared to diesel and JP-4.•Diesel combustion stands out negatively by producing the highest NO emissions (2.27 times higher than kerosene, for ϕ=0.3458 and P3=3017.58 kPa) and the highest total and specific environmental pollution costs for all combustion modes.•Kerosene resulted in the maximum exergy destruction in the burner and in the total turbojet engine.