علی شهرجردی

In this study, numerical simulation of 3D turbulent flow in the silencer with different boundary conditions have done. This analysis was performed using finite volume method and employing ANSYS software. The purpose of this study is to investigate the effect of these geometric parameters on the sound power level between inlet and outlet of the silencer. the geometry of silencer and use of rock wool, which is a kind of sound absorber, has a significant effect on reducing the output sound. According to most standards, including the AMKA standard the sound at the distance of one meter should not exceed 85 dB. Therefore, four parameter of geometric variables were evaluated, which are; the diameter of diffuser holes, the pitch between the holes, number of holes and the length of rock wool area The result show that increasing diameter of diffuser holes, pitch between the holes and number of holes causes sound jets that exit diffuser holes more and flow energy decrease, which increases sound