Husi, GezaManono, Allan Nyaanga2025-06-172025-06-172025-05-26https://hdl.handle.net/2437/393008This thesis studies noise reduction techniques for aircraft engines, particularly emphasizing the high-bypass turbofan engines. Aiming to be in line with international efforts to address environmental problems, this study focuses on the persistent issue of aircraft noise pollution in communities that are surrounded by airports. Technology evaluation is systematically performed through a thorough literature review and sound pressure level measurements. The scientific research found that the high bypass ratio (HBP) engines were effective in decreasing noise due to the great airflow mixing and less exhaust velocities. Technological breakthroughs consisting of chevrons, offset nozzles, swept and leaned stators, FFDs and so on are deeply studied. The methods of Chevrons and FFDs were shown to have an immediate impact on the level of noise, with potential reduction of up to 3 effective perceived noise decibels (EPNdB). The research finds that although each technology has its own advantages, the use of the combination of these methods can probably be the most effective approach to reduce airplane engine noise. This integrated approach would be part of meeting tighter regulations on noise and improving the quality of life of adjacent airport communities without compromising engine performance and economy. More studies are suggested to achieve the best settings of these technologies under different engine types and operation conditions49enThesisEngineering SciencesHozzáférhető a 2022 decemberi felsőoktatási törvénymódosítás értelmében.