400 km/h高速列车受电弓气动噪声分析

Analysis on the aerodynamic noise of the pantograph of high-speed train at 400 km/h

为明确高速列车受电弓系统气动噪声特性及其与流场的关系,建立了受电弓全尺寸模型和缩比子域模型,采用大涡模拟、声扰动方程和FW–H方程预测400 km/h升弓状态下的流场和声场,并基于FW–H方程反演声源分布,基于降阶模型分析底座湍流压力和声压能量分布。研究表明:当来流速度为400 km/h时,以受电弓整体作为声源,远场噪声标准测点的总声压级可达88.1 dB(A),在283、576 Hz附近存在明显峰值,峰值频率对应的斯特劳哈尔数Sr(特征长度取受电弓方杆当量直径41 mm)分别为0.10和0.21;底座湍流压力和声压的前2阶模态能量占比分别为4.5%和3.3%、40.9%和14.0%,且分布呈一定对称性;对于底座,在300 Hz以下频段,全尺寸模型的压力级高于缩比模型,在1 kHz以下频段,全尺寸模型的声压级高于缩比模型;在全频段内,基于全尺寸模型得到的远场测点声压级都高于缩比模型。

In order to clarify the aerodynamic noise characteristics of the high-speed train pantograph system and its relationship with the flow field,a subdomain model of the full size and a scale model of the pantograph were established,and large eddy simulation,acoustic perturbation equation and FW–H equation were used to predict the flow field and sound field under the condition of rising bow at 400 km/h.Based on the FW–H equation,the sound source distribution was inverted,and the energy distribution of the turbulent pressure and sound pressure in the pantograph base were analyzed using the reduced order model.The results show that with the incoming flow velocity of 400 km/h and the pantograph as the sound source,the total sound pressure level of P2,which is the standard measuring point in the far field can reach 88.1 dB(A),and there are obvious peaks around 283 Hz and 576 Hz.The Strouhal number corresponding to the peak frequency(characteristic length is 41 mm equivalent diameter of the square rod)is 0.10 and 0.21,respectively.The energy ratio of the first two modes of the turbulent pressure and sound pressure in the pantograph base are 4.5%and 3.3%,40.9%and 14.0%,respectively,with certain symmetry in the distribution.For the pantograph base,in the frequency band below 300 Hz,the pressure level of the full-size model is larger than that of the scale model,and in the frequency band below 1000 Hz,the sound pressure level of the full-size model is larger than that of the scale model.When the whole pantograph is used as the sound source to radiate to the far-field standard point,the measured sound pressure level of the full-size model is larger than that of the scale model at all frequencies.