Numerical simulation and analysis of the aerodynamic noise of a nautilus-inspired bionic multiblade centrifugal fan

This paper proposes a nautilus-inspired bionic volute for a multiblade centrifugal fan. Analysis of the noises generated by the fan is presented. This is made possible by a model that integrates a steady-state equation using the Reynolds-averaged Navier-Stokes (RANS) model and an unsteady-state estimation using the large-eddy simulation (LES) model and the Ffowcs Williams-Hawkings aerodynamic noise model, and by numerical solution to the model. Our computational model is validated on the sound pressure level with the help of the measurements on a physical system. The validation suggests that the proposed bionic volute significantly increases the aerodynamic performance particularly in terms of transformation between the pressure and flow rate under the rated power. The noise associated to the bionic volute is found to be predominantly tonal noise, and this is the primary source of the noise of the fan. Another finding is that the large expansion profile of the proposed volute contributes to the attenuation of the tonal noise associated to the periodic jet impingement at the impeller outlet.