Analyzing the Performance of Hybrid Silencers ApplyingFinite Element Method

Present paper has analyzed the performance of hybrid silencer using finite element method. Hybridsilencer is efficiently applicable in range of low to high frequencies in ventilation system of automobiles.Hybrid silencer is a combination of plate silencer and absorptive silencer. Configuration ofplate silencer is as follows. When a segment of a rigid duct replaces with a plate backed by a hardwall, incident wave induce vibration to the plate that causes sound reflection. Configuration of absorptivesilencer is as follows. When the rigid duct of an expansion chamber has been lined by apacked absorptive material under a perforated membrane, incident sound waves will be dissipatedby the absorptive liners. Plate silencer usually is applicable for low to medium, and absorptive silencerusually is applicable for low to medium frequency ranges. So, the combination of these twokinds would be so effective in a broad band frequency ranges. Sound reflection occurs just by platevibration, and sound absorption happens by absorptive material. The most important purpose of thispaper is analyzing the transmission loss. Also, analyzing of four different kinds of hybrid silencer isconsidered. Also, the effect of mean flow velocity on the performance of the silencers has been analyzed.

Keywords:

transmission loss , absorptive silencer , plate silencer , hybrid silencer , finite element method