Abstract: Radiation of the flow-induced noise which generated from a centrifugal pump at outside of volute is predicted by computational fluid dynamics (CFD) combined acoustic-vibro-coupling solution through numerical method. The unsteady pressure fluctuations on inner boundary of volute are calculated, which show that the fluctuation amplitude at the region close to volute tongue is relatively higher than the position far away from tongue and the pressure fluctuations at blade passing frequency and its harmonic are markedly higher than other frequencies. It is clear from the acoustic results of volute external-field that the corresponding pressure fluctuation frequency approximates to the fourth natural frequency of structure when Sr equals to 4, the slight resonance would happen between acoustic field and structure and increase the noise radiation at out-field because of the approximated pressure fluctuation frequency and structure natural frequency, which illustrates the structure’s vibration mode has remarkable influence on acoustic calculation. The total sound pressure level results on observation points at out-field reveal these are the integral effect by fluid’s pressure fluctuation and volute’s structure mode on these positions and the sound radiation of out-field keeps at 60 dB roughly.

Key words: Acoustic-vibro-coupling, Centrifugal pump, Flow-induced noise, Numerical prediction