CAJ | 학술논문

为分析隔板对微穿孔管消声器声学特性的影响，该文首先通过试验验证微穿孔管消声器传递损失数值计算方法，然后建立带隔板微穿孔管消声器传递损失的理论模型并利用数值方法进行验证，最后基于理论模型分析了隔板对微穿孔管消声器传递损失的影响。分析发现，隔板位置影响主消声频带及传递损失大小，隔板越靠近中间位置，第一拱形衰减域向高频扩大，且传递损失越大；隔板数目增加，传递损失相应增大，但当隔板数目达到一定值时传递损失不再显著增大；在简单微穿孔管消声器内加隔板后，可以适当缩短膨胀腔长度，而不会明显降低该消声器消声性能，此方法可大大降低消声器的轴向长度，对微穿孔管消声器的优化设计具有指导意义。
위분석격판대미천공관소성기성학특성적영향，해문수선통과시험험증미천공관소성기전체손실수치계산방법，연후건립대격판미천공관소성기전체손실적이론모형병이용수치방법진행험증，최후기우이론모형분석료격판대미천공관소성기전체손실적영향。분석발현，격판위치영향주소성빈대급전체손실대소，격판월고근중간위치，제일공형쇠감역향고빈확대，차전체손실월대；격판수목증가，전체손실상응증대，단당격판수목체도일정치시전체손실불재현저증대；재간단미천공관소성기내가격판후，가이괄당축단팽창강장도，이불회명현강저해소성기소성성능，차방법가대대강저소성기적축향장도，대미천공관소성기적우화설계구유지도의의。
The correctness of the numerical finite element method to calculate transmission loss (TL) of the micro-perforated tube muffler is validated through the measurement of the transmission loss of a micro-perforated tube muffler sample. The transmission loss is measured by a two-load technique that is usually applied to measure the acoustic impedance of micro-perforated panel (MPP) and the transmission loss of various mufflers. A theoretical calculation model of the transmission loss of the micro-perforated tube muffler with a baffle is then established and afterwards verified by the finite element method that has been previously validated. The theoretical model is based on the analysis of a simple pass-through micro-perforated muffler and the plane wave theory. The transfer matrix method is applied to connect the sound pressure and particle velocity of the inlet and the outlet of the muffler. Additionally, boundary conditions and continuity requirements are considered in the theoretical modeling process. Finally, several analyses of the effect of the baffle on the transmission loss of the micro-perforated tube muffler are conducted respectively, which are based on the theoretical model mentioned above. Specifically, two key factors: the axial position of a baffle and the number of the baffles arranged uniformly in the axial direction of the muffler, are under consideration. Five different positions of the baffle lead to different transmission loss curves. In addition, a detailed analysis is given concerned with the baffles number that increases from 0 to 7. Besides, a comparison among three different micro-perforated tube mufflers is given to illustrate the relationship between the baffle and the air cavity length from the aspect of the transmission loss. Consequently, the results of all analyses reveal that, on one hand, the position of the baffle located in the air cavity of the micro-perforated tube muffler alters the main sound attenuation frequency band and the corresponding transmission losses. Furthermore, when the baffle is installed closer to the central cross-section of the air cavity, the first sound attenuation frequency domain arch extends towards the higher frequencies and also the corresponding transmission losses become greater than before. On the other hand, the transmission losses of the micro-perforated muffler with baffles arranged uniformly in the axial direction of the muffler improve with the increasing number of baffles. However, they will not significantly improve once the number of baffles reaches a certain value. Ultimately, we concluded that baffles installed in the air cavity of the micro-perforated tube muffler are beneficial for muffler design to shorten the axial length of the air cavity, thereby shortening the axial length of the entire muffler, without the degradation of sound attenuation performance of the muffler, which is very favorable to reduce the axial dimension of the micro-perforated muffler and thus instructs its optimization and design.