计及气流影响的小长径比插入管消声器声学特性的实验研究

在管内平均气流流速10 m/s~100 m/s范围内,对长径比L/D=0.6的插入管型抗性消声器内部和外部声学特性进行了实验研究。探讨了气流流速大小和消声器结构参数的变化对插入管消声器声学特性的影响,并结合腔内气流涡模态和尾管声学模态对小长径比插入管消声器的声学特性机理进行了分析。实验及理论分析表明,气流流速对消声器内外声学特性均有明显的影响。与消声器静态特性不同的是,在有气流情况下必须计及腔体内上游插入管气流喷射引发的涡模态。计及气流影响的小长径比插入管消声器声学特性与消声器腔内气流再生噪声的涡模态和消声器尾管的声学模态关系密切,而与消声器空腔本体声学模态无关。

Effect of air flow on acoustic characteristics of an insert pipe muffler with a small length-to-diameter radio

The experimental study was carried out on the acoustic characteristics at both inside and outside of the insert pipe muffler at length-to-diameter ratio L/D of 0.60 with the air velocity from 10m/s to 100m/s. The effects of air velocity and structure parameters on the acoustic characteristics of muffler were researched. The acoustic characteristic mechanism of insert pipe muffler with small length-to-diameter ratio was also analyzed according to the vortex mode in muffler and the acoustic mode of tail pipe. It is found that the acoustic characteristics at both inside and outside of muffler are influenced heavily by the air velocity. The most difference from the acoustic characteristics of muffler without flow is the vortex mode generated by the jet flow of upstream inlet pipe in muffler must be analyzed at the study on acoustic characteristics of muffler with flow. The acoustic characteristics of insert pipe muffler at small length-to-diameter ratio with flow are close related with the vortex mode of air regeneration noise in muffler and the acoustic mode of tail pipe.