Modeling of Particulate Emissions From Conventional and Sustainable Jet Fuels in Aero Engine Combustors

Abstract Non-CO2 emissions are the major factor that contributes to the climatic impact of the aviation sector. In addition to reducing net-CO2 emissions, drop-in sustainable aviation fuels (SAF) can lead to a reduction in particulate emissions. The latter may act as condensation nuclei for water vapor to form condensation trails (contrails). However, studies have shown that the differences in particulate emissions of both total soot particle mass and number density between conventional jet fuel and SAF depend on the aero engine operating point. A more detailed assessment of soot emissions along a flight mission requires modeling the soot particle formation including the particle size distribution (PSD), incorporating detailed thermodynamic information of the aero engine and chemical fuel characteristics within reasonable computational time and accuracy. This study applies a chemical reactor network with finite-rate chemistry and a sectional soot model combined with an aero engine performance model to evaluate the soot particle mass, particle number and PSD along with further combustion emissions at various aero engine operating points. Simulations are carried out for different SAF types and compared to conventional Jet-A fuel. The model results show a reduction in soot mass of up to 73% and the formation of fewer large soot particles when using SAF surrogates.