Study the Performance of Turbofan Engines under the Effect of Changing Chevron Nozzle Geometry

In this study, the effect of changing the geometry of the chevron nozzle on the performance of turbofan engines is investigated. The study aims to characterize new chevron geometry configurations to investigate how to reduce the jet noise of turbofan engines while achieving minimal impact on engine thrust. To this end, a numerical analysis of the chevron nozzle with different geometries will be performed. The model is validated and compared with experimental and numerical data from the literature. Circular, elliptical, and triangular chevron cutout patterns with different penetration lengths are selected for the jet acoustic characterization of chevron nozzles. These cutouts are applied to both the core nozzle and the fan nozzle, resulting in a double chevron nozzle. The numerical study is performed using a steady 3D density-based k-ε turbulence model. The numerical results are compared with the base nozzle model with no cutout. It was found that best performing geometry in terms of minimizing noise level with gain in thrust compared to the base nozzle model was the circular-shaped Chevron with core diameter to penetration length ratio (penetration ratio) of 5 (DC 5). Furthermore, it was also found that increasing the penetration length will increase the thrust gain of the engine.