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Simulation of the particle oxidation catalyst POC (R) acoustics
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).ORCID iD: 0000-0001-7898-8643
2014 (English)In: Noise Control Engineering Journal, ISSN 0736-2501, E-ISSN 2168-8710, Vol. 62, no 5, 368-374 p.Article in journal (Refereed) Published
Abstract [en]

The reduction of the exhaust noise from internal combustion engine (IC-engine) is mainly managed by proper silencer design, while less attention is paid to the acoustic performance of the after treatment devices (ATD). It is known from the earlier studies, that the transmission loss of a typical ATD unit can be quite significant. An ATD unit for diesel engines is classically assembled from several specific parts such as selective catalytic reducers (SCR), diesel oxidation catalysts (DOC) and diesel particulate filters (DPF). One new alternative to the conventional DPF is the particle oxidation catalyst (POC (R)). The POC (R) substrate studied in this paper is of type POC-X, which consists of fine, corrugated metallic wire mesh screens piled askew and rolled into a cylindrical shape. In this paper acoustic two-port simulation models for POC-X are proposed. First model is built up starting from the classical Kirchhoff solution for prediction of the acoustic wave attenuation in narrow channels. According to experimental studies, correction factors to the narrow channel two-port model are proposed. Second model is derived by treating the filter as a lumped acoustic resistance, dependent on the flow resistivity coefficients obtained from the pressure drop measurements.

Place, publisher, year, edition, pages
2014. Vol. 62, no 5, 368-374 p.
Keyword [en]
Acoustics, Catalysts, Catalytic oxidation, Diesel engines, Engines, Oxidation, Pressure drop, Acoustic performance, Acoustic resistance, After treatment devices, Cylindrical shapes, Diesel oxidation catalyst, Diesel particulate filters, Oxidation catalysts, Pressure drop measurements
National Category
Other Engineering and Technologies
URN: urn:nbn:se:kth:diva-158456DOI: 10.3397/1/376236ISI: 000346128200009ScopusID: 2-s2.0-84912530026OAI: diva2:776959

QC 20150108

Available from: 2015-01-08 Created: 2015-01-08 Last updated: 2015-12-14Bibliographically approved
In thesis
1. Acoustic In-duct Characterization of Fluid Machines with Applications to Medium Speed IC-engines
Open this publication in new window or tab >>Acoustic In-duct Characterization of Fluid Machines with Applications to Medium Speed IC-engines
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The unwanted sound, noise, can lead to health problems, e.g. hearing loss and stress-related problems. A pre-knowledge of noise generation by machines is of great importance due to the ever-shorter product development cycles and stricter noise legislation. The noise from a machine radiates to the environment indirectly via the foundation structure and directly via the surrounding fluid. A fluid machine converts the energy from the fluid into mechanical energy or vice versa. Examples of the fluid machines are internal combustion engines (IC-engines), pumps, compressors, and fans. Predicting and controlling noise from a fluid machine requires a model of the noise sources themselves, i.e. acoustic source data. In the duct systems connected to the fluid machines, the acoustic source interacts strongly with the system boundaries, and the source characteristics must be described using in-duct methods.

Above a certain frequency, i.e. first non-plane wave mode cut-on frequency, the sound pressure varies over the duct cross-section and non-plane waves are introduced. For a number of applications, the plane wave range dominates and the non-plane waves can be neglected. But for machines connected to large ducts, the non-plane wave range is also important. In the plane wave range, one-dimensional process simulation software can be used to predict, e.g. for IC-engines, the acoustic in-duct source characteristics. The high frequency phenomena with non-plane waves are so complicated, however, that it is practically impossible to simulate them accurately. Thus, in order to develop methods to estimate the sound produced, experimental studies are also essential.

This thesis investigates the acoustic in-duct source characterization of fluid machines with applications to exhaust noise from medium speed IC-engines.  This corresponds to large engines used for power plants or on ships, for which the non-plane wave range also becomes important. The plane wave source characterization methods are extended into the higher frequency range with non-plane waves. In addition, methods to determine non-plane wave range damping for typical elements in exhaust systems, e.g. after-treatment devices, are discussed.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2015. xi, 63 p.
TRITA-AVE, ISSN 1651-7660 ; 2015:86
in-duct, acoustic source, source characterization, IC-engine
National Category
Fluid Mechanics and Acoustics
urn:nbn:se:kth:diva-177341 (URN)978-91-7595-765-4 (ISBN)
Public defence
2015-12-10, sal F3, Lindstedtsvägen 26, KTH, Stockholm, 10:00 (English)

QC 20151119

Available from: 2015-11-19 Created: 2015-11-18 Last updated: 2015-12-14Bibliographically approved

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