Pros and Cons of Using Different Numerical Techniques for Transmission Loss Evaluation of a Small Engine Muffler Istituto Motori CNR

Format:

Conference/Event

Author/Creator:

Siano, Siano, author.

Contributor:

Auriemma PhD, Fabio

Bozza, Fabio

Conference Name:

Small Engine Technology Conference & Exposition (2010-09-28 : Linz, Austria)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2010

Summary:

Automotive exhaust systems give a major contribution to thesound quality of a vehicle and must be properly designed in orderto produce acceptable acoustic performances. Obviously, noiseattenuation is strictly related to the used materials and to itsinternal geometry. This last influences the wave propagation andthe gas-dynamic field.The purpose of this paper is to describe advantages anddisadvantages of different numerical approaches in evaluating theacoustic performance in terms of attenuation versus frequency(Transmission Loss) of a commercial two perforated tube mufflerunder different conditions.At first, a one-dimensional analysis is performed through the 1DGTPower® code, solving the nonlinear flow equations whichcharacterize the wave propagation phenomena. The muffler ischaracterized as a network of properly connected pipes and volumesstarting from 3D CAD information.Then, two different 3D analyses are performed within thecommercial STS VNOISE® code. The first one assumes rigid wallhypothesis. In the second, a preliminary FEM modal analysis of thestructure is realized. The computed structure natural frequenciesare then imported in the BEM model in order to carry out thecomplex fluid-structure interaction. The effects of this lastcondition on TL calculation are compared and discussed. Inaddition, both flow and temperature effects have been included inthe modeling and discussed with the previous analyses. Agreementamong these numerical evaluations and related limitations are putinto evidence for different configurations

Notes:

Vendor supplied data

Publisher Number:

2010-32-0028

Access Restriction:

Restricted for use by site license