<b>Soot Formation in a High-Pressure Swirl-Stabilized Flame</b>

<p dir="ltr">Soot is a detrimental byproduct of gas-turbine combustion which can negatively affect environmental, human, and mechanical health. The reduction of particulate emissions is critical to the sustainability of aircraft. Laser-induced incandescence (LII) is a diagnostic method that allows for in-situ measurements of soot within flames. Using this technique, soot formation was studied in a high-pressure swirl-stabilized combustor operating at conditions representative of aviation engines. LII measurements were taken in both pilot and full flame conditions with both traditional jet fuel (Jet-A) and Hydroprocessed Esters and Fatty Acids (HEFA) produced synthetic aviation fuel (SAF). All conditions showed a clear dependence on the equivalence ratio of the pilot flow with higher equivalence ratios demonstrating increased soot formation. Additionally, the SAF demonstrated a significant decrease in the amount of soot formed in comparison to Jet-A flames. These measurements represent a step forward in understanding the formation of particulate emissions in aviation engines. With greater understanding more efficient and sustainable combustion systems may be developed.</p>