Noise Reduction of the Engine Cooling Fan Used in Large Bus

Abstract

Acoustic considerations of axial flow fans become imperative due to regulations and the ubiquitous call for environment-friendly products. This paper suggests a noise reduction method for the engine cooling fan. This engineering model has been developed for the prediction of the noise spectrum of an axial flow fan. The radiated acoustic pressure is expressed as the discrete frequency noise peaks at the BPF and its harmonics and line spectrum at the broad band by noise generation mechanisms. This paper shows a comparison of the measured and calculated noise spectra of the fan for the validation of the noise prediction program. This paper also presents the characteristics of fan noise due to modify the design parameters. Accordingly, design parameter values for noise reduction of the fan were obtained.