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Investigation into modeling of multi-perforated mufflers
KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strömningsakustik.ORCID-id: 0000-0001-7898-8643
2009 (engelsk)Konferansepaper, Publicerat paper (Annet vitenskapelig)
Abstract [en]

There is a strong competition among automotive manufacturers to reduce the radiated noise levels. One main source is the engine where the main noise control strategy is by using efficient mufflers. Resistive mufflers are now widely used to attenuate IC-Engine noise due to its better performance over the reactive ones. Resistive damping can be achieved either by using absorbing material or perforates in the form of tubes or sheets. Perforates mufflers have an increased performance with flow when the acoustic impedance is increased by introducing flow through the perforate holes. On the other hand, perforates can deteriorate the engine performance, if badly designed, by increasing the flow back pressure. Modeling of perforated mufflers started in the seventies when simple geometries were used. There were two approaches to analyze two tubes connected with a perforate (i.e. four-port), segmentation and distributed. Both approaches were limited to a few specified geometries. Recently, the authors published a new technique based on the segmentation approach where four ports can be replaced by a number of two-ports so that it can be used in general two-port codes. This paper investigates the use of these techniques in modeling complex perforated muffler geometries. Fifteen different configurations were modeled and compared to measurements. There are some limitations to the use of these models in some configurations because of strong 3D effects that limits the validity of these models to almost half the plane wave region. These configurations are mainly the double plug flow muffler and the parallel tube mufflers.

sted, utgiver, år, opplag, sider
2009.
HSV kategori
Identifikatorer
URN: urn:nbn:se:kth:diva-103695Scopus ID: 2-s2.0-84871465187OAI: oai:DiVA.org:kth-103695DiVA, id: diva2:561260
Konferanse
16th International Congress of Sound and Vibration, Krakow (2009)
Merknad

QC 20121018

Tilgjengelig fra: 2012-10-18 Laget: 2012-10-18 Sist oppdatert: 2012-10-18bibliografisk kontrollert
Inngår i avhandling
1. Investigation and Optimization of the Acoustic Performance of Exhaust Systems
Åpne denne publikasjonen i ny fane eller vindu >>Investigation and Optimization of the Acoustic Performance of Exhaust Systems
2012 (engelsk)Licentiatavhandling, med artikler (Annet vitenskapelig)
Abstract [en]

There is a strong competition among automotive manufacturers to reduce the radiated noise levels. One important source is the engine exhaust where the main noise control strategy is by using efficient mufflers. Stricter vehicle noise regulations combined with various exhaust gas cleaning devices, removing space for traditional mufflers, are also creating new challenges. Thus, it is crucial to have efficient models and tools to design vehicle exhaust systems. In addition the need to reduce CO2 emissions puts requirements on the losses and pressure drop in exhaust systems. In this thesis a number of problems relevant for the design of modern exhaust systems for vehicles are addressed. First the modelling of perforated mufflers is investigated. Fifteen different configurations were modeled and compared to measurements using 1D models. The limitations of using 1D models due to 3D or non-plane wave effects are investigated. It is found that for all the cases investigated the 1D model is valid at least up to half the plane wave region. But with flow present, i.e., as in the real application the 3D effects are much less important and then normally a 1D model works well. Another interesting area that is investigated is the acoustic performance of after treatment devices. Diesel engines produce harmful exhaust emissions and high exhaust noise levels. One way of mitigating both exhaust emissions and noise is via the use of after treatment devices such as Catalytic Converters (CC), Selective Catalytic Reducers (SCR), Diesel Oxidation Catalysts (DOC), and Diesel Particulate Filters (DPF). The objective of this investigation is to characterize and simulate the acoustic performance of different types of filters so that maximum benefit can be achieved. A number of after treatment device configurations for trucks were selected and investigated.

Finally, addressing the muffler design constraints, i.e., concerning space and pressure drop, a muffler optimization problem is formulated achieving the optimum muffler design through calculating the acoustic properties using an optimization technique. A shape optimization approach is presented for different muffler configurations, and the acoustic results are compared against optimum designs from the literature obtained using different optimization methods as well as design targets.

sted, utgiver, år, opplag, sider
Stockholm: KTH Royal Institute of Technology, 2012. s. iv, 18
Serie
Trita-AVE, ISSN 1651-7660 ; 2012:31
Emneord
Exhaust systems, noise, pressure drop, 1D models, perforated mufflers, after treatment devices, optimization
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-103595 (URN)
Presentation
2012-10-14, Faculty of Engineering, Ain Shams university, Kairo, Egypt, 09:15 (engelsk)
Opponent
Veileder
Forskningsfinansiär
TrenOp, Transport Research Environment with Novel Perspectives
Merknad

QC 20121016

Tilgjengelig fra: 2012-10-16 Laget: 2012-10-16 Sist oppdatert: 2013-04-11bibliografisk kontrollert

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