Numerical Analysis to Centrifugal Impeller Aeroacoustics
Liu Qiuhong,Qi Datong,Mao Yijun
(School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’ an 710049,China)

Abstract: The prediction method for identifying the acoustic source generated from a centrifugal impeller is developed. To predict the acoustic field, the three-dimensional unsteady flow fields and unsteady forces fluctuations are calculated by solving Navier-Stokes equations with SIMPLEC algorithm. The results show that the aeroacoustics is dominated by tones at blade passage frequency and the higher harmonics in a centrifual impeller with vaned deffuser. To reveal the effects of the moving sound source, three acoustic formulas are applied to calculat e the acoustic pressure. It is indicated that the moved acoustic source remarkably disturbs the intensity of acoustic field with obvious Doppler effect, the variation of acceleration can be neglected, the whole rotating impeller is reason ably regarded as a dipole source with simple harmonic motion.
Keywords: unsteady flow, centrifugal impeller, aeroacoustics.