车用交流发电机气动噪声数值分析

以某型车用交流发电机（也称爪极发电机）为研究对象，采用计算流体力学技术对交流发电机的空气动力学特征进行了三维非定常数值模拟，应用滑移网格技术和大涡模拟方法对交流发电机进行气动噪声特性研究。得到大涡模拟在交流发电机噪声数值预测方面其主要阶次和对应的幅值与试验对比有很好的一致性；前后扇叶为该型交流发电机的气动噪声声源；第6、8、10、12和18等阶次为该型交流发电机的主要气动噪声成分。在数值模拟基础上，以低噪声、高流量为优化目标，对交流发电机前端盖径向栅格分布角度进行气动噪声优化设计及降噪研究。得到前端盖径向栅格倾斜40°分布角度时交流发电机远场气动噪声最低、质量流量最大。文中所得研究成果可为车用交流发电机的气动性能和高转速下噪声的改进提供一种切实可行的参考依据。

Numerical Simulation Analysis on Aerodynamic Noise of the Vehicle Alternator

The characteristics of three-dimension flow dynamics of a certain type of vehicle alternator (claw-pole alternator) are simulated numerically with computational fluid dynamics technique. The sliding mesh technology and large eddy simulation are applied to study the aerodynamic noise of alternator. The numerical predictions of main alternator noise orders and their magnitudes obtained by LES are in good consistency with experimental results. The front and rear blades are the aerodynamic noise sources for this type of alternator. The main components of aerodynamic noise are the 6 th, 8 th, 10 th, 12 th and 18th orders. On this basis of numerical simulation, taking low noise and high flow as an optimal object, study the optimal design and noise reduction of aerodynamic noise about the angle of front end cover to radial grid. After changing the 40°angle of front end cover to radial grid, it is obvious that not only the total noise is lowest but also the mass flow rate is highest. This research can provide practical reference for the improvement of aerodynamic performance and high speed noise for vehicle alternator.