[关键词]
[摘要]
一般牵引电机噪声由冷却风扇噪声、电磁振动噪声和机械噪声组成,其中冷却风扇引起的气动噪声是重要构成部分。建立牵引电机整机计算流体动力学(CFD)计算模型,利用DES-SST湍流模型计算牵引电机内流场,通过回转面、子午面上流线和旋涡强度分布发现风扇流道内流动分离现象十分显著,风扇进风口及叶尖处存在高强度的旋涡运动。建立牵引电机整机气动噪声有限元计算模型,以非定常流场计算结果为声源预测牵引电机辐射噪声。计算结果表明,噪声监测点上仿真计算值与试验值的总声压级最小相差0.1 dB(A),多点平均声压级相差1.8 dB(A),计算结果较准确。牵引电机气动噪声由离散噪声和宽频噪声组成,其中离散噪声的最高峰值来自于冷却风扇的偶极子噪声,且风扇叶片不等间距排列导致叶片通过频率的基频由369 Hz偏移至221 Hz。同时该频率下噪声的辐射指向性呈现典型的偶极子特征,并主要从牵引电机进出风口向外传播。试验结果可为牵引电机降噪优化工作提供参考。
[Key word]
[Abstract]
The noise of traction motor is composed of cooling fan noise, electromagnetic vibration noise and mechanical noise, in which the aerodynamic noise caused by cooling fan is an important part. The computational fluid dynamics(CFD) calculation model of the traction motor is established, and the DES-SST turbulence model is used to calculate the flow field in the traction motor. Through the streamline and vortex intensity distribution on the rotating surface and meridional surface, it is found that the flow separation phenomenon in the fan channel is very significant, and there is high-strength vortex motion at the fan air inlet and blade tip. The finite element calculation model for the aerodynamic noise of the traction motor is established,and the calculation result of the unsteady flow field is used as the sound source to predict the radiated noise of the traction motor. The calculation results show that the minimum difference of total sound pressure level at the noise monitoring points between the simulation calculated value and the test value is 0.1 dB(A), and the difference of average sound pressure level at multiple points between simulation and test is 1.8 dB(A). The calculation results are accurate. The aerodynamic noise of traction motor consists of discrete noise and broadband noise. The highest peak of discrete noise comes from the dipole noise of cooling fan, and the unequal spacing arrangement of fan blades causes the fundamental frequency of blade passing frequency to shift from 369 Hz to 221 Hz. At the same time, the radiation directivity of noise at this frequency presents a typical dipole characteristic and mainly propagates outward from the air inlet and outlet of traction motor. The research can provide reference for the noise reduction optimization of traction motor.
[中图分类号]
[基金项目]
中国中车电机基础研究科研项目(YJXM2017-022)