Influence of Turbofan Engine Design Parameters on Aircraft Environmental Impact

Abstract

Despite the emergence of new energy carriers and propulsion systems architectures, turbofan engines power the majority of commercial aircraft. Therefore, aviation’s environmental impacts are significantly influenced by the design of these turbofan engines. Hence, we should drive the design of modern turbofan engines, informed with each design parameter’s effect on environmental implications, namely the climate and air quality impacts. To understand the connection between the engine design parameters and an aircraft’s environmental impact, it is important to have the capability to quantify the environmental impact resulting from a combined “Aircraft-Engine- Operation” scenario. Through modeling and connecting aircraft, engines, flight operations, emissions, and their resulting impacts on climate and air quality, we can link the end-to-end impact propagation chain and evaluate the outcomes of any engine design alteration. We investigate free design variables such as overall pressure ratio (OPR), fan pressure ratio (FPR), and turbine entry temperature (TET), as well as technology level indicators such as component efficiencies, cooling, and material temperature capability. Sensitivities are calculated for three different reference engines, and the differences in trends between the engines are analyzed. Influence of external-to-aviation uncertainties and valuation choices are also illustrated. Comparison between Jet-A and different sustainable aviation fuels (SAFs) are conducted from an environmental and societal point of view. The study also explores how the derived influence coefficients or sensitivities can provide valuable guidance to stakeholders when making decisions regarding technological investments, design space change, or regulatory assessments.