高速受电弓气动噪声特性分析

摘要

针对高速列车受电弓气动噪声声源组成的复杂性和各部件对总噪声的贡献量问题,基于Lighthill声学理论,采用三维、宽频带噪声源模型,LES大涡模拟和FW-H声学模型对DSA380型高速受电弓气动噪声进行数值模拟,分析该型受电弓的主要气动噪声声源特性及各部件对受电弓远场气动噪声的贡献量大小,并提出降噪改进意见.研究结果表明:受电弓主要噪声源为弓头、绝缘子、底架、下臂杆等组件的迎风侧位置,其中碳滑板、平衡臂、弓头支架、底架、绝缘子、下臂杆等部件对远场气动噪声声源的贡献量最多;受电弓气动噪声是宽频噪声,且主要能量集中在160~2 500 Hz,存在主频305、608、913 Hz(350 km/h运行),且各阶主频与运行速度均满足线性关系;相邻2测点满足2倍关系的横向受声点声压级,其衰减幅度大约为6 dBA,且与横向距离的对数成线性关系;垂向受声点的声压级最大值出现在距地面高度7.192 m处;运行速度不改变受电弓的偶极子噪声指向特性(垂向平面在θ=0°、纵向平面在θ=120°、横向平面在θ=90°处的噪声指向性明显),只改变其幅值,随着运行速度的增大其增加幅度越小;受电弓以开口方式运行的气动噪声性能较闭口方式好,降噪效果明显.%In response to the complexity of sound sources of aerodynamic noise of high speed train pantograph, and the noise contribution of each component to the total noise, based on Lighthill''s acoustic analogue theory, three-dimensional broadband noise source model, large eddy simulation and FW-H acoustic model, carried out numerical simulation of aerodynamic noise of the DSA380 high-speed train pantograph, to analyze the characteristics of the main aerodynamic noise of the pantograph, and the contribution of each component to far field aerodynamic noise of the pantograph.Noise reduction advice was proposed.The computational results showed that pantograph noise mainly rooted in the windward side of panhead, insulators, base frame, and lower arm rod.Carbon skateboard, balance arm, panhead support, base frame, insulators, lower arm rod had maximum contribution to the far-field aerodynamic noise.Pantograph aerodynamic noise was broadband noise and the main energy was concentrated in the range of 160~2 500 Hz.The order frequencies of far-field aerodynamic noise were 305 Hz, 608 Hz and 913 Hz (at the speed of 350 km/h) and each order frequency was linearly related to the running speed.The attenuation amplitude of sound pressure level of horizontal noise evaluation points with spacing of adjacent two points meeting two times requirement was about 6 dBA.The horizontal noise evaluation points and logarithm of transverse distance were of a linear relationship.The maximum sound pressure level of the vertical noise evaluation points appeared at 7.192 m high from the ground.The running speed did not change the directional characteristic of dipole noise of pantograph (the noise directivity was obvious when the vertical plane was at θ=0°, the longitudinal plane was at θ=120°, and the transverse plane was at θ=90°), but just changed its amplitude.With the increase of running speed, the amplitude became smaller.The aerodynamic noise performance when the pantograph operated with the "knuckle" between the pantograph arms facing backward was better than that when the pantograph operated with the "knuckle" facing forward.