Computation of the Flow of a Dual-Stream Jet with Fan-Flow Deflectors for Noise Reduction

This paper studies the impact of installing noise-suppressing deflector vanes in the bypass flow on the aerodynamic performance of the dual-stream supersonic nozzle of a turbofan engine by using a three-dimensional Reynolds-averaged Navier-Stokes computer program. A series of nozzle configurations using a single pair or double pairs of vanes with NACA0012, NACA4412, and NACA7514 airfoil profiles are investigated. The effects of the azimuthal mounting position of the deflector vanes, angle of attack, and shape of the airfoils are studied. The flow field around the vanes, overall flow turning angle, reduction of turbulent kinetic energy, thrust loss, and blockage caused by the deflector vanes are examined. Recommendations regarding the choice of airfoil and mounting configurations are made for best noise suppressing effectiveness with minimum loss of thrust and mass flow.