Abstract:

Abstract: In views of the aerodynamic noises generated by axial fan, a three-dimensional model of this kind of fan is built. Lighthill acoustic analogy theory, FW-H acoustic wave equation and FLUENT numerical simulation are used to analyze the characteristics of aerodynamic noises arisen from the axial fan’s rotating blades. The simulation result shows that the static pressure of rotating blades is mainly distributed on the front side of blades. However, the fluctuating pressure is distributed on both sides and mainly in the margin of blades, which is caused by the severe air turbulence from the vortexes in the outer edge of blades. The acoustic power of blades is also distributed in the margin of blades, but its characteristic of distribution is different from that of fluctuating pressure, indicating that the aerodynamic noises of rotating blades are not all produced by fluctuating pressure. In addition, the faster the blades rotate or the larger the blade’s diameter is, the more intense the aerodynamic noise is.

摘要：

针对某型轴流风机引起的气动噪声问题，建立该型轴流风机的三维模型，利用Lighthill声类比理论、FW-H声波波动方程和Fluent数值模拟，分析该轴流风机旋转叶片引起的气动噪声的噪声特性。数值模拟结果表明，旋转叶片上的静态压力主要集中在旋转方向前方的叶面上；而脉动压力则在叶片的两个面上均有分布，分布区域主要集中在叶片的外缘，这是由于叶片外缘脱落的旋涡引起的剧烈的气流震荡所导致。叶片上的气动噪声功率主要分布在叶片的外缘，其分布规律与脉动压力的分布规律有差异，表明旋转叶片的气动噪声并不完全由脉动压力产生。旋转叶片所诱发的气动噪声随着叶片转速和风机直径的增大而增大。

关键词: 声学, 轴流风机, 旋转叶片, 气动噪声, FW-H方程, Fluent 软件