空调对车内噪声影响的仿真分析

Study on the Influence of Air Conditioning Sound Source on Stationary Interior Noise

为研究市域列车空调系统对车内噪声的影响,本文结合边界元法和声线跟踪法,建立了市域列车空调声源车内噪声仿真模型,模型在低频区(160 Hz以下)使用边界元法,考虑了空调机组和风道气流等声源在空调风道以及客室车厢内传播的特性,在高频区(160 Hz以上)使用声线跟踪法,最终得到整个频段的车内噪声。选取车内中心距离地板1.6 m高度处的声压级仿真与试验结果进行对比,结果显示试验与仿真曲线的变化趋势基本一致,声压级总值相差1 dB以内,各频段声压级差值在5 dB以内,验证了声学模型的准确性。最后应用该模型对空调降噪措施进行了仿真,当仅存在空调声源时,在管道底部铺设2 m的玻璃丝绵可降低车内噪声4.0 dB(A)。

In order to study the influence of the air conditioning system on the interior noise of the city train,this paper combines the boundary element method and the sound ray tracking method to establish a simulation model of the interior noise of the air conditioning sound source of the city train.The model uses the boundary element method in the low frequency region(below 160 Hz).Considering the characteristics of the sound source of the air conditioning unit and the air flow in the air conditioning duct and the passenger compartment,the sound ray tracking method is used in the high frequency region(above 160 Hz),and the interior noise of the whole frequency band is finally obtained.The sound pressure level simulation and test results at a height of 1.6m from the floor in the center of the vehicle are compared.The results show that the change trend of the test and simulation curves is basically the same.The total sound pressure level difference is within 1dB,and the sound pressure level difference of each frequency band is within 5 dB,which verifies the accuracy of the acoustic model.Finally,the model is used to simulate the noise reduction measures of air conditioning.When there is only air conditioning sound source,laying 2 meters of glass sponge at the bottom of the pipe can reduce the interior noise by 4.0 dB(A).