Abstract
This paper describes an application of active noise controlto reduce blade passing noise for centrifugal fans using an adaptive feedforward control structure. Most of studies for reducing fan noise are associated with aerodynamics and discuss the influence of different geometric parameters. In recent years, a variety of research have achieved the active cancellation (ANC) of noise in ducts. A proposed noise control system with a ontrol loudspeaker mounting at the cutoff region of the fan is designed. The controller based on the filtered-X LMS (least mean squares) with multi-sine reference input and frequency counting has accelerated the convergence of the algorithm by using a digital signal processor (DSP).Experiments are carried out to evaluate the proposed designfor reducing the fundamental blade passing noise and harmonic frequency noise at various flow rates. The results of experiment indicate that the synthetic, periodic noise generated by loudspeaker can be reduced up to 25dB and blade passing noise from a practical centrifugal fan can be reduced up 6 to 7 dB.