Research progress on noise reduction of centrifugal fans

Centrifugal fans, as a widely used type of gas transport equipment, have noise reduction research that is of great significance for enhancing working environments, mitigating noise pollution, and extending equipment service life. With advancements in high-speed and miniaturization of centrifugal fans, the contribution of quadrupole sources to aerodynamic noise has become increasingly prominent. Existing noise control methods, which primarily target monopole and dipole noise, are gradually reaching their limits in the face of increasingly stringent acoustic performance requirements. In this paper, generation mechanisms and noise reduction principles of aerodynamic noise have been summarized systematically, and based on the fundamental properties of acoustic waves, noise-reduction mechanisms at the source have been classified into two main categories: sound source amplitude attenuation and destructive interference. The applications and advancements of traditional and bionic noise reduction methods in centrifugal fans have been elaborated, with respect to the reduction in the amplitude of sound source, the induction of destructive interference, and the psychoacoustic optimization. Finally, key challenges such as quadrupole noise control and the analysis of structure-flow-acoustic coupling mechanisms have been discussed, and potential future research directions have been outlined, aiming to provide references for the design and optimization of a new generation of low-noise, high-efficiency centrifugal fans.