청소기용 터보홴의 공력소음 발생에 관한 수치적 연구

A new method to calculate the aeroacoustic pressure of a centrifugal fan was developed. The fan consists of an impeller, diffuser and circular casing. Due to the high rotating velocity and the small gap between the impeller and diffuser, the centrifugal fan makes very high noise level at BPF and its harmonic frequencies. The aeroacoustic pressure is calculated acoustic analogy. In this paper, only dipole term is considered in the equation. The acoustics generated by moving impeller and stationary diffuser is calculated separately. The unsteady flow field data is calculated by the vortex method. The predicted acoustic pressure agrees very well to the measured data. The difference of the two is smaller than 3㏈A.