Abstract
Recently, there has been growing interest in high rotational axial flow fan for cooling the sever. The aerodynamic noise generated by fans has two main components; rotation noise and broadband noise. However, previous research in this field has been limited to noise reduction by changing the blade shape, and concentrated on one-dimensional analysis. The primary focus of this paper is to analyze the fan noise in the three-dimensional acoustic space, and reduce the noise by controlling fan's phase. In the reciprocity theorem, acoustic transfer function is represented by volume velocity of sound source and sound pressure of the receiving point, and is established even if each place is changed. When making a three-dimensional model, it is necessary to consider resonance in the radial direction in relatively large acoustic space. The analysis model was designed using the calculation result in the one-dimensional acoustic duct, then the sound particle velocity was calculated to add the fan noise characteristic.
