Optimization of Bypass Outlet Guide Vane for Low Interaction Noise

An optimization approach has been developed and applied to a fan stage representative of a modern turbofan engine to achieve novel, realistic, low-interaction-tone noise bypass outlet guide vanes with acceptable mechanical and aerodynamic properties. The incorporation of axial sweep in the design of the bypass stators is used as a passive method to achieve sizeable reductions in the discrete frequency tones generated by the impingement of the fan wakes. The acoustic benefits, mechanical properties, and aerodynamic performance of an unconventional sweep profile of the stator leading edge have been investigated numerically in an optimization framework using a combination of computational fluid dynamics and finite-element methods to solve each part of the problem. The results obtained in two separate optimizations to reduce interaction noise at the noise-critical sideline operating condition are presented and analyzed.