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 build a family 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.