声学与CFD分析用于小型挖掘机的噪声控制

摘要

针对某小型挖掘机辐射噪声较大的现状，应用频谱分析方法，识别主噪声源为发动机排气噪声。对原消声器进行了三维声场与流场分析，结果表明对100 Hz～160 Hz频段消声量明显不足。对三管迷路消声器进行了参数优化，分析了穿孔率、穿孔孔径、中间管管径及进气管插入深度等对传递损失的影响，穿孔率与穿孔孔径对传递损失影响不大，中间管管径越小、插入深度越大，中低频消声效果越好。实测结果表明，优化后消声器中低频消声量明显提高，与分析结果非常吻合，机外辐射噪声降低了3.1 dB(A)之多，且背压降低达86.1%。%In view of the large radiation noise of a small excavator, the exhaust noise was found to be the main noise source using spectrum analysis method. The sound field and CFD of the original muffler of the excavator were simulated. The simulation results showed that the noise elimination of the original muffler was obviously insufficient in the frequency range from 100 Hz to 160 Hz. Then, the parameters of the impedance mixed muffler with three tubes were optimized. The ef-fects of perforation rate, diameter of the holes, diameter of the middle tube and insertion depth of the inlet on transmission loss were analyzed. The results show that perforation rate and diameter of the holes have little effect on the transmission loss. Small diameter of the middle tube and large insertion depth can lead to good noise elimination effect in low and median frequency ranges. The test results show that after the optimization of the muffler, the noise elimination effect is raised obvi-ously in low and median frequency range, which is consistent with the results of the analysis. The radiation noise has been re-duced by 3.1 dB (A), and the back pressure of the exhaust has been reduced by 86.1%.