Turbofan Engines Efficiency, Historical Trends, and Future Prediction: A Review

Abstract

Technological development in the aviation business is usually dictated by diverse safety, economic, environmental, and social goals set by governments, regulatory agencies, and the market. Recently, a rapidly increasing interest in making air transportation climate neutral has been observed. The objective of this study is to analyze the historical trends of aircraft engine fuel efficiency, identify parameters affecting engine efficiency and initiate a discussion about future technology development needed to meet the expectations. The commercial turbofan engines test data comparison is provided in this study, followed by a theoretical assessment. The presented test data trends show a clear correlation between specific fuel consumption decrease and engine parameters like bypass ratio and overall pressure ratio increase, which is confirmed by theoretical assessment. Based on performed analysis results, a bypass ratio increase was indicated as the one potential path to reduce aircraft engine fuel consumption. Bypass ratio improvement could be achieved by fan diameter increase and rotation speed reduction in the case of turbofan engine architecture. A larger fan rotor requires a high torque drive and significantly increases engine weight which could be compensated by the lightweight design of the engine components, e.g., by applying composite materials.