Prediction of Flow and Acoustical Performance of an Automotive Exhaust System using 3-D CFD TATA Technologies Limited

Format:

Conference/Event

Author/Creator:

Sen, Sen, author.

Conference Name:

SAE 2011 World Congress & Exhibition (2011-04-12 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2011

Summary:

An automotive exhaust system composed of several elements is oneof the most important aggregates in a vehicle in defining theengine efficiency and passenger comfort. Therefore it is veryessential to understand the flow characteristics inside the exhaustsystem thoroughly to keep the back pressure and noise level wellwithin the limit. The recent widespread use of three-dimensional(3-D) numerical tools and methods has enabled automotive engineersto predict the performance of exhaust system at the early stages ofvehicle program.The present paper describes the application of 3-D computationalfluid dynamics (CFD) using Fluent (V12.0) in an automotive exhaustsystem to predict the back pressure and noise concurrently. A 3-Dcomputational domain consisting of exhaust runner/downpipe,catalytic-converter (CAT-CON), silencer with internal details andtail pipe was generated. Extra care was taken by extruding prismlayers while generating the mesh to capture the near wall effectsand smallest acoustic pressure fluctuations. First a steady stateanalysis using realizable k-ε turbulence model with non-equilibriumwall functions was carried out to study the velocity and pressurefield. To resolve the acoustic pressure fluctuation unsteady RANSsimulation was executed followed by large eddy simulation (LES).Ffowcs-Williams and Hawkings (FW-H) model was used to obtainfrequency versus sound pressure level (SPL) at receiverlocation.The simulation results of flow field, id est, back pressure andSPL were compared with experimental results. It confirms that theexhaust system can be modeled with good accuracy for low backpressure and improved sound quality using CFD approach with FW-H topredict the sound pressure level at desired locations. Thus it hashelp to reduce the cost and development time by giving betterinsights to the design

Notes:

Vendor supplied data

Publisher Number:

2011-01-1068

Access Restriction:

Restricted for use by site license