多腔穿孔消声器声学特性三维时域计算及评估

Three-dimensional time-domain computation and evaluation of acoustic performance of multi-cavity perforated muffler

为有效降低涡轮增压器泄气声,改善声品质,设计了多腔穿孔消声器.基于三维计算流体动力学（CFD）计算无流条件单腔穿孔结构的传递损失,与有限元法（FEM）计算结果相吻合,验证准确性,并研究不同结构参数对声学性能的影响.采用CFD法分别计算无流、平均流条件下消声器的传递损失,频率小于2 000Hz消声性能良好,气流的存在使得高频区域传递损失有所增大,消声峰值及其对应频率无明显变化规律.安装消声器于压气机进气口侧,试验获得进气管口＂泄气＂噪声谱、声压级总值及插入损失,结果表明宽频泄气噪声成分得到显著降低.通过声品质参数后处理分析,3种工况下响度值降低幅度达19%~38%,而尖锐度变化不大.整车试验评估表明,所设计的多腔穿孔消声器消声效果显著,声品质改善明显.

In order to minimize the snuffling noise caused by turbocharger and improve the sound quality, a multi-cavity perforated muffler was designed to be attached in a vehicle. Firstly the CFD approach was used to calculate the transmission loss （TL） of a single-cavity element without flow. Being consistent with the result calculated by FEM, CFD approach is proved to be validated towards this. And the influence on acoustic performance of such various structural parameters is achieved as well. Furthermore, the TL of such muffler, in the case of with/without the mean flow, was calculated by the CFD approach. In result, it performs well among the range of frequency below 2 000 Hz. The intake airflow tends to make TL be higher in the high frequency, but the amplitude and frequency of damping peaks are irregularly moved. At- taching the muffler to the inlet of compressor, the noise spectrum, sound pressure level and insertion loss were achieved, which indicates the wide-band noise is attenuated remarkably. According to the post-pro- cessing of certain parameters of sound quality, under the three different test conditions, the loneness is re- duced 19%-38% in amplitude respectively, however the sharpness is increased a little in fact. Such multi- cavity perforated muffler has been proved excellent in acoustic performance according the road test, the sound quality has been improved apparently as well.