船用离心风机流动诱发振动噪声数值研究

Numerical Study of Fluid-Induced Vibrational Noise of a Marine Centrifugal Fan

针对进出口连接有长管道的离心风机系统,其外部辐射噪声主要是内部非定常流动诱发蜗壳振动产生的振动噪声。基于风机振动噪声问题,给出了一种考虑振声耦合作用的流场-结构-声场单向耦合数值计算方法,并通过振动试验验证了此单向耦合数值计算方法的有效性,随后基于声辐射贡献量分析(PACA)方法定量的给出了噪声源位置。研究表明:振动噪声的基频分量占据主导地位,蜗壳表面声压主要由蜗壳表面振动速度或是振动加速度决定。噪声源分析表明,蜗壳侧板出口靠近蜗舌区域、蜗壳前、后板距离蜗舌180°附近区域是蜗壳基频振动噪声辐射的主要振动噪声源。

Concerning the fan system with the long pipelines connected on the inlet and outlet,the structural vibration noise is the main component of the external radiated noise,and is caused by the volute vibration which is excited by the unsteadyflow.Based on the vibrational noise of fan volute casing,a method of numerical calculation of unidirectional coupling of fluid-structure-sound was proposed,and the rationality of this method was verified by vibration measurement of the volute casing.Then the positions of the noise source of the volute casing was studied and revealed applying the panel acoustic contribution analysis(PACA)method.It can be concluded that the vibrational noise of volute casing at blade passing frequency(BPF)is predominant,and the normal vibration of the volute was the decisive factor that determined the volute surface acoustic radiation.The analysis results of the PACA of each component of the volute show that the outlet of the side volute close to the volute tongue area,and the volute front and back panel at 180°near the volute tongue,were the main noise source regions.