The flow and aeroacoustics analysis of simple expansion chambers
Date Issued
2010
Date
2010
Author(s)
Tsai, Yi-Wen
Abstract
The purpose of this research is to investigate the simple chamber noise which is induced by pressure variation in the turbulent flow. The SIMPLE algorithm with finite volume based scheme was used in this numerical analysis, and Reynolds Averaged Navier-Stokes equations combine with Rk-ε turbulent model are used to solve the turbulent flow. In order to establish the analysis experiences and understand the effect of flow induced noise on the performance of a muffler, uniform flow passes through a 2D muffler is analyzed firstly. The influences of flow velocities and the parameters, such as length, radius, inlet/outlet extended pipe length and so on, on the turbulence noise generation are discussed. Three specific mufflers are simulated, and are compared with the experimental datum to verify the accuracy before starting 3D muffler analysis. The result of simulation and experiment datum show that they have qualitative relationship. Therefore, 3D muffler is analyzed according to this model. For the sound field analysis, the flow induced noise in the interior of a muffler is computed by the Broadband Noise Source (BNS) model. Proudman’s and Curle’s formula were used to evaluate acoustic power per unit volume and surface acoustic power. In this study, we focus on the total aerodynamic noise generated when the fluid pass through a muffler, and analyze different flow velocities and the parameters to understand how the aerodynamic noise is generated. Hoping that this study would improve muffler’s performance.
Subjects
simple chamber
air
turbulence
aerodynamic sound
BNS
Type
thesis
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