OPTIMIZATION OF ACOUSTIC AND AERODYNAMIC PERFORMANCE FOR A LOW NOISE TRANSONIC FAN AT SIDELINE CONDITION

As the bypass ratio of turbofan engines increases, rotor-stator interaction noise has become the dominant noise component. Traditional rotor-stator interaction noise reduction techniques, such as swept and leaned stators, often lead to unacceptable aerodynamic losses. This study presents an integrated optimization approach of acoustic and aerodynamic performance for a transonic fan model at sideline condition. The stator is designed to be swept and leaned, while the leading edge is designed to be wavy. Based on the understanding of three-dimensional physical flow field, the parameters of the swept-and-leaned design and the local shape of the leading edge are iteratively optimized. To minimize computational costs while maintaining accuracy, the nonlinear harmonic method is utilized to predict the sound source intensity. Through various iterations, the process of rotor-stator interaction is effectively optimized, leading to a suppression in the unsteady response of the stator and minimizing the aerodynamic losses related to flow separation. A noise reduction exceeding 5 dB for the first blade passing frequency (BPF) without incurring substantial aerodynamic losses is reached.