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.