Effect of Stator Stagger Angle on Rotor-stator Interaction Noise

An integrated computational approach, containing the nonlinear harmonic (NLH) method and boundary integral equation method (BIEM), is introduced for the prediction of rotor-stator interaction noise. The mode decomposition method is used for the evaluation of upstream sound wave. The stagger angle of stators is adjusted by 5 and 10 degrees clockwise and counterclockwise. Two specific examples from the performance curves are selected for the investigation: (1) near design point with same mass flow; (2) high flow point with same outlet static pressure. The aerodynamic performance of each case is analyzed, including velocity amplitude of rotor wakes, and harmonic loading on the stator vanes. The sound radiation upstream inside the duct is assessed for each case with different stagger angles. The results show that even a small vane inclination can affect the sound generation process, especially at higher harmonics. It was observed that a 10-degree variation in the stator stagger angle can result in 6-8 dB difference in SPL at 2BPF of two specific examples.