Assessing the Impact of Turbofan Engine Design on Aircraft Contrail Properties

Abstract Reducing the impact of aircraft-induced radiative forcing must be explored in a multidisciplinary manner regarding CO2 and non-CO2 effects for the aviation sector to reach its net-zero goal by 2050. In the current work, a detailed turbofan engine cycle model has been developed and used to buildafamily of engines with varying design parameters. The engine system is used to assess exhaust conditions and fuel efficiency, in addition to sizing a parametric engine geometry. A machine learning framework has been trained on ground measurement data, and a methodology developed to predict in-flight emissions based on engine design parameters and cruise requirements. These models have been used in conjunction with high fidelity CFD utilizing a previously developed ice microphysics module to simulate contrails behind a fully featured aircraft at cruise. It is found that the number of non-volatile particulate matter emitted dictates ice crystal size and optical depth, with a reduction in emissions reducing the radiative forcing of the produced contrail. Improvements in fuel efficiency achieved through increased bypass or overall pressure ratio also work to reduce the impact of a contrail, but only if particle emissions remain similar. The type of combustion is found to have the greatest impact on contrail properties.