轴流泵内部流动诱导噪声数值研究

为改善轴流泵运行的稳定性,采用CFD方法和Lighthill声比拟理论,利用CFX对模型泵在0.55Q_(BEP)、0.6Q_(BEP)、0.9Q_(BEP)、Q_(BEP)、1.1Q_(BEP)流量下的轴流泵内部流场进行非定常模拟,并基于CFX数值模拟所得到的流动信息,根据FW-H方程提取叶片表面偶极子声源,并在LMS Virtual.Lab中采用内外声学直接边界元模型计算不同工况下的模型泵内叶频及其谐频处的内声场。研究结果表明,泵内边界上最大声压值随着流量的减小逐渐增大;叶片偶极子噪声在叶频96Hz处的深度失速工况泵内边界声压比最优工况下增大了28.9%;壳体偶极子噪声在轴频24Hz处的深度失速工况泵内边界声比最优工况下增大了6.5%,在叶频96 Hz时的深度失速工况泵内边界声压高于最优工况7%。

Numerical Study of Flow Induced Noise in Axial-flow Pump

In order to improve the operation stability of axial-flow pump, based on the CFD method and the Lighthill acoustic analogy theory, CFX was used to simulate internal unsteady flow field of model pump under the conditions of 0.55QBEP,0.6QBEP, 0.9QBEP,1.0QBEP and 1.1QBEP discharge. Based on the information obtained by the CFX numerical simulation, the FW-H equation was adopted to extract dipole acoustic source of blade surface. And then the acoustic boundary element model in LMS Virtual. Lab was used to calculate internal sound field of model pump in the blade frequency and its harmonic frequency under different working conditions. The results show that the maximum sound pressure on the pump boundary increases gradually with the flow rate decreasing. The blade dipole noise at frequency 96 Hz under the deep stall condition of pump pressure increases by 28.9% than that of optimal operating condition. The shell dipole noise at the shaft frequency at 24 Hz under the deep stall condition of the pump increases by 6.5% than that of optimal operating condition, and at the blade frequency 96 Hz under the deep stall condition, the pump boundary sound pressure is 7% higher than that of optimal operating condition.