Gas turbine nvPM formation and oxidation semi-empirical model for commercial aviation

Several semi-empirical relations have been developed to estimate nonvolatile particulate matter (nvPM) mass emissions from rich-quench-lean (RQL) style combustors employed predominantly in the current aviation fleet. The accuracy of such methodology has been hindered by inaccurate combustor conditions. Additionally, current relations are not optimized for direct cruise nvPM emission predictions and do not account for fuels, in particular alternative jet fuels with reduced aromatic contents. An improved semiempirical kinetic based predictive relation has been developed for these purposes. Accurate engine conditions are based on proprietary engine cycle data for a common RQL style combustor. Nonvolatile particulate matter formation rates dependent on equivalence ratio, thrust, and fuel components are developed to accurately predict emissions across thrust settings and fuels. The new model captures both ground and cruise altitude emissions. To incorporate fuel effects hydrogen content is used as it encompasses all three fuel components: aromatics, paraffins and cycloparaffins. Predicted values are validated against field campaign data collected over a decade from NASA Langley's Aerosol Research Group with inclusion of cruise data.