利用COMSOL软件模拟直通穿孔消声器内声波传播过程,发现模拟结果与实验测试结果较为吻合.为此,本文借助其系统地研究扩张比、扩张腔长度、穿孔孔径和穿孔率等参数对实际发动机排气消声器声学性能的影响规律,结果表明:消声器传递损失随着扩张比增大而增大,但增大的幅度不断缩小;扩张腔长度仅对大于250 Hz频段内消声器传递损失的影响较为显著,且其值越大消声器高频消声效果越好;穿孔孔径对小于500 Hz频段内消声器传递损失的影响较小,但在其它频段内消声器传递损失随穿孔孔径增大呈现先减小后增大的趋势;随着穿孔率不断增大消声器传递损失在小于250 Hz频段内呈先增大后减小的趋势,而在其它频段内呈不断减小的趋势,且减小的幅度不断缩小.%The sound propagation process in the straight-through perforated pipe silencer was calculated by using the COMSOL acoustics module. It is found that the simulated results are in good agreement with experimental results. Therefore, the effect of such parameters as the expansion ratio, expansion chamber length, perforation diameter, and perforation rate on the acoustic performances of automobile engine exhaust muffler was systemati-cally studied by this module. Research results show that the transmission loss of exhaust muffler increases with the increasing expansion ratio, but the increasing degree is reduced continuously; the expansion chamber length has a significant influence on the transmission loss of exhaust muffler above the 250 Hz, and larger length cor-relates with greater transmission loss at high frequency; the transmission loss of exhaust muffler is less affected by perforation diameter below the 500 Hz, but the transmission loss of exhaust muffler decreases first and then increases with the increase of perforation diameter at other frequency band;the transmission loss of exhaust muf-fler first increases then decreases below the 250 Hz, while decreases continuously at other frequency band while the weakening is reduced continuously with the increase of perforation rate.
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