Modeling and Performance Evaluation of a Simple Reactive Muffler of Vehicles Using CFD
| dc.contributor.advisor | Edessa, Dribssa (PhD) | |
| dc.contributor.author | Dessalegn, Abera | |
| dc.date.accessioned | 2020-11-30T09:43:50Z | |
| dc.date.accessioned | 2023-11-18T06:32:18Z | |
| dc.date.available | 2020-11-30T09:43:50Z | |
| dc.date.available | 2023-11-18T06:32:18Z | |
| dc.date.issued | 2012-01 | |
| dc.description.abstract | One of the components in the exhaust system of vehicle is muffler. The purpose of the muffler is to reduce the exhaust noise produced by the engine. The main objective of this study is modeling performance evaluation of a simple reactive muffler of vehicles using CFD. Simple expansion chamber muffler has been modeled numerically using Computational Flu id Dynamics (CFD) in order to determine its acoustic response. The CFD model consists of an ax isymmetric grid with a single period sinusoid of suitable amplitude and duration imposed at the inlet boundary. The time history of the acoustic pressure and par ticle velocity is recorded at two points, one point in the inlet pipe and the other point in the outlet pipe. These time histories a re Fourier transformed and the Transmission Loss (TL) of the muffler is calculated. The mean flow has also been considered. The mean flow model of the muffler is done using finer mesh and with a suitable inlet velocity applied at the inlet boundary and the pressure drop across the muffler is found. The performa nce of the muffler is evaluated based on Transmission Loss, Insertion Loss and Backpressure. The simulation of the muffler was carried out using FLUENT software package. GAMBIT was used to create a mesh and to define the boundary condition of the required object, which is ready and analyzed by FLUENT. The version used is FLUENT 6.3.26. The solver implemented was an axisymmetric, segregated implicit solver with second order implicit time stepping. Second order upwin discretization was used for the density, momentum, energy, turbulent kinetic energy and turbule dissipation rate equations. PISO pressure velocity coupling is used. The k - for closure. The working fluid was air with the density modeled assuming an ideal gas. The bounda conditions consist of a velocity inlet, a pressure outlet and a series of walls. The CFD results are compared with numerical results. Transmissions Loss vs. frequency curves are analyzed. Expansion chamber mufflers have been widely studied and results show that the larger the expan ratio the greater the Transmission Loss. It is a good practice to design a muffler to work best in the frequency range where the engine has the highest sound energy. | en_US |
| dc.identifier.uri | http://etd.aau.edu.et/handle/12345678/23734 | |
| dc.language.iso | en_US | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | Transmission Loss (TL) | en_US |
| dc.subject | Back pressure (BP) | en_US |
| dc.subject | Insertion Loss (IL) | en_US |
| dc.title | Modeling and Performance Evaluation of a Simple Reactive Muffler of Vehicles Using CFD | en_US |
| dc.type | Thesis | en_US |