Impact of Operating Regime on Aviation Engine Emissions: Modeling Study

This work is focused on the numerical analysis of pollutant formation in an aviation gas turbine engine at different values of power setting. The analysis is conducted on the basis of a comprehensive approach treating the reactor net model for description of nonequilibrium chemical processes inside the combustor and the quasi-one-dimensional model to compute the evolution of species concentrations in the postcombustor flow. Special attention is paid to the study of the formation of volatile aerosol precursors: sulfuric and nitrous acids and organic compounds. The applied approach provides a reasonable agreement between predictions and measurements of emission indices for main pollutants NOx, CO, CnHm SO2, and HNO2. It is shown that, whereas the concentrations of the main components of combustion exhaust, NOx, CO, CO2, and H2O, vary only slightly in the turbine and nozzle flow, the concentrations of sulfur compounds (SO3 and H2SO4) and other condensable species (CH2O, HNO2, and HNO3) can change noticeably. The simulation also demonstrates that the concentration of organic condensable matter (CH2O, CH3OH, and C2HO) in the engine exhaust can be comparable to (or even greater than) the concentration of sulfuric acid at 85 and 30% power setting, even at a moderate value of sulfur fuel content (400 mg/kg).