S.Esmail Razavi - Assistant Professor, Sahand University of Technology
Babak Harsini - Graduate Student, Iran University of Science and Technology
S.M Hasheminejad - Associate Professor, Iran University of Science and Technology

An expansion chamber is investigated from fluid flow and noise reduction point of view. This silencer is analyed considering noise reduction and minimizing the pressure losses. The unsteady flow in expansion chambers is investigated and noise reduction is performed employing FFT (Fast Fourier Transform) analysis. Pressure losses are computed in three dimension turbulent flow within expansion chambers by FLUENT. Single and double expansion chambers are used. Numerical results show a drastic reduction in noise level, when double chambers are utilized while increasing pressure losses. The numerical results obtained by the present study are compared to that of other investigators, in which good agreement would exist.

Unsteady flow, FFT analysis, Noiso reduction, Navier-Stokes Equations