叶片出口角影响离心泵噪声辐射数值研究

运用FEMBEM声振耦合计算方法分析叶片出口角对离心泵在水动力激励下泵壳振动辐射噪声影响。采用大涡模拟方法模拟离心泵内部瞬态流场，获得蜗壳壁面偶极子声源；对泵壳体结构进行模态分析获得结构模态响应；利用LMS Virtual Lab间接边界元IBEM声振耦合模块计算非定常流动引起的离心泵内部噪声，并与实验数据对比，验证基于LES、声振耦合的噪声数值模拟方法可行性。计算离心泵外场噪声及声辐射，研究叶片出口角度对离心泵外场噪声辐射影响。结果表明，离心泵叶片通过频率BPF处的辐射声功率随叶片出口角的增大而增大；外场噪声声压级指向性分布显示叶片出口角存在合适范围，使泵在小流量工况运行时噪声较小。

Numerical study on effect of blade outlet angle to centrifugal pump noise

The FEMBEM acoustic-vibro-coupling method was applied to study the effect of blade outlet angle to centrifugal pump noise caused by the hydrodynamic forces. Firstly, the large eddy simulation method is used to solve the transient flow field of the pump, and the volute surface dipole was obtained. Secondly, the modal of the pump housing structure is analyzed using the finite element method (FEM). Lastly, the acoustic-vibro coupling module of the Virtual Lab software was employed to study the interior sound fields of the pump caused by the unsteady flow. By comparing the computational results with experimental ones, the validation of the LES combined with the FEMBEM methods for centrifugal pump noise computation was verified. On this basis, the outer sound fields were investigated, and the effect of blade outlet angle to outer sound fields was studied. The results show that the sound power at the BPF becomes large as the blade outlet angle increase; the blade outlet angle should be at suitable range to ensure a lower noise level at low flow rates.