某型高速列车车厢连接处脉动压力的预测与控制

Prediction and Control of Fluctuating Pressure at the Inter-coach of Certain Type Highspeed Train

某型高速列车以350 km/h运行时,靠近车厢连接处的乘务室在40 Hz频率下对应的声压级高达105 dB。为明确该噪声的产生根源并有针对性地进行控制,采用子域法建立了车厢连接处的气动仿真模型,使用改进延迟涡分离模型进行脉动压力预测。经分析车厢连接处上、下缺口测点压力功率谱密度发现,射流剪切层存在接近40 Hz的峰值频率,该频率与车厢连接处所围区域形成的声学空腔的二阶模态频率接近,由此产生了共振。仿真分析表明:在上、下缺口前端与末端增加波浪板能明显降低测点在36~45 Hz对应的脉动压力总能量。实车测试表明:该方案能使乘务室在40 Hz下对应的声压级降低5 dB。主动射流方案也有较好的降噪效果,有望在未来成为可实施的方案。

When certain high-speed train runs at the speed of 350 km/h,the sound pressure level of attendant cabin near the inter-coach is up to 105 dB at the center frequency of 40 Hz.In order to identify the noise source and apply specific control,subdomain method is used to establish the aerodynamic simulation model of the inter-coach.The improved delayed detached eddy simulation model is used to carry out the fluctuating pressure prediction.By analyzing the pressure power spectral density of the measuring points located at the upper and lower gaps,it is found that there is a peak frequency close to 40 Hz in the jet shear layer,which is close to the second-order mode frequency of the acoustic cavity surrounding the inter-coach and generates resonance.Numerical analysis shows that adding wave plate to the front and back end of upper and lower gaps can obviously reduce fluctuating pressure total energy of the measuring points at the frequencies from 36 Hz to 45 Hz.Practical vehicle test results show that the plan can lower sound pressure level of attendant cabin by 5 dB at the center frequency of 40 Hz.The active jet scheme shows better noise reduction effect,and it is expected to become an actual implementation scheme in the future.