Abstract
Multiblade fan noise is large and has various frequencies. The purpose of this study is to clarify the relationship between the internal flow and fan noise using a numerical analysis. In particular、frequency analysis of the pressure fluctuation on blade surface was performed in order to clarify the source of noise. By frequency analysis result、high pressure fluctuation occurred at the impeller side of leading edge in the pressure and suction side. In addition、broadband pressure fluctuation occurred at the shroud side of the leading edge in the pressure side and at the impeller side of the leading edge in the suction side. This broadband pressure fluctuation is caused by reverse flow and stagnation between the blades、and circulation flow in the casing. These are the cause of the broadband noise of 100∼250 Hz.
