基于三维声波波动方程的有限元软件LMS Virtual．lab Acoustics，采用两种不同的研究方法获得了消声器的传递损失，第1种方法是采用定义入口单位质点振速的方法；第2种方法是采用AML（ Automatically Matched Layer ）技术直接计算声功率的方法．结果表明两种方法计算出来的结果高度一致，且第2种方法计算步骤简单、计算速度快，对于大截面管路消声器也同样适用．相对传统的传递矩阵法和依靠经验的方法，用三维声学有限元法，在计算速度上有很大的提高，并且有效地减少了基于一维平面波理论所产生的消声器传递损失计算误差．最后利用第2种方法，研究了基于气流速度影响的消声器出口辐射噪声，并建立了其插入损失的有限元计算模型．%This paper presents two different methods for the study of transmission loss of mufflers based on three-dimensional acoustic wave equation using the finite element software LMS .Virtual Lab Acoustics .The first method used defined unit velocity of particle vibration on the inlet; another method used technology of AML to calculate sound power .The results show that the calculation results of the two methods are highly consistent .The second method has simpler calculation steps and faster calculation speed and it is suitable for the large cross -sec-tion duct muffler;Compared with the traditional transfer matrix method and the empirical method ,the calculation speed has been improved by using the three-dimension acoustic finite element method , and the transfer error of muffler based on one-dimensional plane waves has been effectively reduced .Finally, the radiation noise of muf-fler outlet was studied in the second method based on the effect of flow velocity , and the finite element calcula-tion model of insertion loss was also established .
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