温度场影响下的某消声器声学性能研究

Study on Acoustic Performance of a Muffler under the Influenced of Temperature Field

在车辆运行的时候,消声器内部普遍有很大的温度梯度。为了准确研究某型号消声器在车辆运行时的声学性能,首先建立消声器模型,同时用Hypermesh划分所需网格;然后使用Fluent计算出车辆运行时消声器的内部流场,通过实验验证仿真正确性;再用热声耦合的方式将CFD求解结果作为声学边界条件,计算出该消声器在有温度场影响下的消声器传递损失。通过与常温常压下的传递损失对比,结果表明:在温度场的影响下,该消声器传递损失峰值会往高频移动,尤其是2200 Hz~2800 Hz尤为明显;低频段消声量有所减少,减少量约为2 dB~3 dB;高频端消声量有所增加,增加量约为23 dB。

There is generally a large temperature gradient inside the muffler when the vehicle is operating.In order to accurately study the acoustic performance of a muffler in the vehicle operating condition,the muffler model is established and the Hypermesh code is used to build the finite element mesh.Fluent software is used to calculate the internal flow field of the muffler in the vehicle operation condition.The simulation accuracy is verified through experiments.Then,with the result of CFD solution as the acoustic boundary condition,the transmission loss of the muffler under the influence of temperature field is calculated by means of thermo-acoustic coupling method.Compared with the transmission loss under normal temperature and pressure,the research results show that:under the influence of the temperature field,the peak value of the transmission loss of the muffler will shift to high frequency side,especially in the range of 2200 Hz-2800 Hz;the noise amount is reduced by 2 dB-3 dB in the low frequency band;the amount of sound elimination at the high-frequency end is increased by about 23 dB.