Abstract: As the second part of the ‘Low noise design of fan outlet guide vane’ serial articles, this paper numerically evaluates the rotor/stator interaction noise of the two swept and leaned Outlet Guide Vanes (OGVs) obtained in the first paper and explored the noise reduction mechanism. First, a non-linear harmonic method is adopted to simulate the fan stage with different OGVs. The perturbation pressure on several sections and blade surface of OGV is investigated and analyzed. It is found that the perturbation pressure amplitudes of the low-noise design OGVs and the interaction noise are significantly reduced. Then, the optimized combination of sweep and lean resulted in a different distribution of phase on the blade surface. The radical variation of phase enhances the cancelation of the response of OGV to the rotor wake, being conducive of noise reduction. Finally, Wilson's wave splitting method is employed to quantitatively evaluate the sound power levels. The results show that, the rotor/stator interaction noise is reduced dramatically due to the low noise design, and a minimum of 5 dB of noise reduction can be obtained at different power sets except at take off for the 1st BPF.

Key words: high bypass ratio turbofan, aerodynamics-acoustics integrated design, rotor/stator interaction noise, non-linear harmonic method, mode analysis