Experimental Study on The Performance of Circular Mufflers with Different Placement of Baffles

• Main Authors: Shih-Yun Yang, 楊詩韻
• Other Authors: Ying-Chun Chang
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/01145829356466447415

碩士 === 大同大學 === 機械工程學系(所) === 97 === This article mainly probes into the configuration of the vertical baffle and the sound muffling material in a circular muffler, doing measurement analysis in order to know a better configuration within a muffler. Among the variable parameter, the material with variation includes: the interval between the vertical baffles, the number of sound muffling material, and the layout of the baffle and the sound muffling material. The following is the experiment of the noise-damping capability, analyzing the experiment data, and making the sound-penetrating-loss spectrum and the octave spectrum to let us know clearly that when the layout is different, the noise-damping capability is different. The initial experiment is to use the number of sound muffling material and the interval of the front baffle as the variable parameter. It is found that when the interval of the baffles is narrowing and the number of the sound muffling cotton pad is increasing, the noise-damping capability is raising conspicuously. Also, when the baffle and the sound muffling material are horizontal or vertical to each other, it could considerably decrease the noise when the source of the noise enters the hush pipe because the reflecting paths are different. It’s clear that according to the sound-penetrating-loss spectrum, the differences can be seen clearly when it’s without baffles. When the frequency is at 1000Hz, the amount of the noise could reduce to 55dB. The capability difference is smaller after adding one or two sound muffling pads, but when it is comparing with three sound muffling pads, the reduction of the amount of noise when at high frequency, 3000~5000Hz, is growing obviously and steadily, and noise-damping capability at low frequency is comparatively increasing when adding the baffle and the sound muffling material. Apart from that, the influence of the different sound muffling material characters to the muffler starts to increase clearly after 800Hz, and the effect to high frequency is also obvious.