Analysis of potential soot breakthrough during oxidation at aero-engine relevant conditions

Reducing emissions from aero-engines, vital for aviation climate goals, requires accurate prediction of pollutants like soot. In modern rich-quench-lean aero-engine combustion chambers, fresh air is introduced after the primary combustion zone to dilute the rich exhaust gases and to cool the combustor liner walls, which will consequently also lead to the oxidation of soot with O. In this study, a simplified configuration is derived from the actual aero-engine configuration that enables an in-depth analysis of these soot oxidation processes. Detailed chemistry, together with the split-based extended quadrature method of moments soot model, is used for a comprehensive analysis of soot oxidation, focusing on the influence of varying scalar dissipation rates, mixing times, and particle size distributions derived from the real combustor. It is shown that soot oxidation linearly connects to the oxidation time scale represented by the OH residence time, meaning more soot breakthrough with shorter oxidation times. Furthermore, the influence of the soot particle size distribution is investigated. By connecting the oxidation time and the soot particle size, a metric to quantify soot breaking through the mixing zone into the lean regions of the combustion chamber is proposed.