Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/1726
標題: 具有內部隔板與通道之突張式消音器性能的實驗研究
Experimental Study on the Performance of Sudden Expansion Silencer with Inner Baffle-Wall and Connnecting Duct
作者: 游川倍
You, Chuan-bei
關鍵字: sudden expansion silencer;突張式消音器;baffle-wall;connecting duct;porosity ratio;隔板;直管通道盪;孔隙比
出版社: 機械工程學系
摘要: 
本文主旨在探討具有週期性脈衝入流對垂直隔板與直管通道的突張式消音
器整體消音性能的影響。改變進出口管長度、不對稱度、孔隙比、直管長
度與高度等等,以了解各參數對整體消音器性能的影響。實驗中進氣基頻
的頻率範圍在10∼120Hz之間,突張式消音器之擴張比=7.5。針對消音器
性能的估測,本實驗採用消音器內部壓力量測以及下游噪音量測相比較。
結果證實:兩種量測結果隨著進氣基頻改變之分布相當吻合,僅在高頻時
之噪音稍大。孔隙比較大之模型,在低頻的消音性能會比較好,高頻時反
而比較差。在消音器模型中僅加入垂直隔板時,會使消音器的性能稍微改
善。在消音器模型中同時加入垂直隔板與直管通道時,會使消音器的消音
性能變好,尤以低頻域者為甚。當直管高度較小時,將會阻隔更多低頻的
能量通過直管通道,使得消音器出口的低頻域噪音量更小。另外,直管長
度較長時,會使消音性能稍微變好。而當消音器模型之進出口為不對稱時
,其消音效果會較對稱者好。不對稱度愈大的模型,其消音效果愈好。當
加長進口管時,會增加高頻域的聲壓位準。而加長出口管時,會使其發生
最大值的頻率往低頻方向移動。若沒加出口管時,其聲壓位準會隨著進氣
基頻的增加。綜合本實驗中各參數變化的結果,以具有垂直隔板且直管高
度較小之不對稱模型的消音性能最好,故未來可向此方向發展。關鍵詞:
突張式消音器、隔板、直管通道、孔隙比

This study investigates the performance of sudden expansion
silencer with internal baffle-wall and connecting duct in
relation to some design parameters. Such parameters are the
length and the asymmetry of input and output ducts, the length
and height of the connecting duct as well as the porosity ratio.
The inflow frequency ranges from 10Hz to 120Hz. The evaluation
is based on the magnitude of pressure variation within and sound
level measurement downstream of the silencer . Frequency
responses of both pressure variation and the sound level are
coincident for frequency lower than 100Hz. However, deviation
arises for frequency higher than 100Hz because of the presence
of small scale eddy in the exhaust jet. Large porosity ratio can
eliminates the noise level at low frequency range. Noise
reduction is significant while the internal baffle-wall is
inserted. Besides, the longer the connecting duct, the more
reduction of the sound level. The height of the connecting duct
determines the passage of energy at lower frequency. Thus, small
height of the connecting duct can reduce effectively the sound
level at low frequency range, and vice versa. Furthermore,
longer inlet duct can increase the sound level at frequency
higher than 100Hz. On the other hand, the longer outlet duct
will decrease the resonant frequency of the flow tone inside the
silencer. In the limiting case of no tail duct, the resonant
frequency locates beyond 120Hz and the sound level is high
within 00z In gnraly, h betperormne o nis reutio ca e atane
ifthe veticl bfle-al i intlle isie teasymeti siener Beies,
smaller eghtofth conctig uc an uitblelngt o te ilt ad utet ducts
cn hlp olocteth reoantfreuncyofth flwton inie tesilencer
Hihporsiy ati an lsob faoabl torduc te oun eve atlow
frquecyrage.Keyword: suden xpnson iencr、aflewal Bconctig
duc、orsit ati
URI: http://hdl.handle.net/11455/1726
Appears in Collections:機械工程學系所

Show full item record
 

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.