Experimental investigation of the impact of organic contents and fuel (kerosene and SAF) on soot oxidation

Soot oxidation is a critical process which directly impacts particulate emissions, yet remains insufficiently understood due to the complex interactions between surface growth and oxidation mechanisms. The present study isolates the oxidation from competing processes by using a two-stage burner configuration. By combining optical diagnostics, based on Phase Doppler Anemometry (PDA), Multiple Wavelength Thermal Emission (MTWE) and Multi-Angle Static Light Scattering (MASLS), the local flame temperature, velocity, soot volume fraction and particle size of soot experiencing oxidation are assessed. The impact of soot composition on oxidation efficiencies of particles generated from propane with different amount of organics, kerosene (Jet A-1) and Sustainable Aviation Fuel (SAF) is then investigated. The results reveal that, even under the same environmental conditions, significant differences in oxidation behavior across fuel types are observed. Surprisingly, in certain cases, mass reduction aligns with more effective agglomeration processes. This work, which considers the fractal nature of the soot aggregates, provides new expressions of oxidation rates for aeronautics fuels of interest thus giving precious inputs for numerical models allowing to understand aircraft emissions and to improve control strategies. Novelty and Significance Statement This study enhances the understanding of soot oxidation mechanisms by isolating oxidation from surface growth using a two-stage burner setup. Through various optical diagnostics, we assess the temporal evolution of soot temperature, volume fraction, and size, providing insights to improve numerical models predicting aeronautical emissions. Examining the effects of soot organic composition and comparing fuels like Jet A-1 and Sustainable Aviation Fuel (SAF), we note significant differences in oxidation behaviors. This research aids in developing effective control strategies and supports the shift to cleaner fuels, advancing sustainable aviation.