中文摘要：

贯流风机的通过频率（BPF）是其重要的噪声频率。降低BPF噪声可以降低基频处的声压级，其中一种方法是采用不等距叶片。本文采用3种叶片距分布形式，采用realizableκ-ε两方程和大涡模拟（LES）湍流模型模拟了风机的内流场，计算线性欧拉方程（LEE）中声源项得到声源位置及强度，采用基于Lighthill声类比的FW-H积分方程获得了叶轮和蜗舌处偶极子型的离散噪声频谱。比较了不同叶片距对风机性能，噪声特别是BPF噪声的影响。计算结果表明在对性能影响较小的情况下，不等距叶轮可降低BPF噪声和总A声级噪声。

英文摘要：

the blade passing frequency（BPF） is a most important noise frequency of the cross-flow fan. The BPF noise could be depressed by using the variable pitch blades, the viscous flow fields of three different pitch impeller are computed by using realizable κ - ε and large eddy simulation（LES） turbulence models. The location and intensity of the sound source could be get by compute the sound source item of the liner Euler equation （LEE） and the discrete noise frequency spectrums of the impeller and the stabilizer are computed by FW-H equation which develops from the Lighthill＇s equation. Through comparing the computing results of the performance and the noise characteristics, it indicates that the variable pitch impeller could depress the BPF noise and the sound A level noise.