On acoustic in-duct characterization of medium speed IC-engine exhaust system

Antti Hynninen, Mats Åbom

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

Abstract

Predicting and controlling noise from a fluid machine requires a model of the noise sources themselves, i.e., acoustic source data. If the source connects weakly to the surroundings, the standardized free field methods can be used for the source sound power determination, i.e., source characterization. In the duct systems connected to the fluid machines, the acoustic source interacts strongly with the system boundaries and the in-duct source characteristics cannot be described using only the emitted sound power. The following general problems exists: The source characteristics are dependent on the acoustic load and the sound power is reflected from the duct discontinuities as well as from the duct terminations, the sound pressure measurements might be contaminated by the turbulence in the flow, and 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 nonplane wave range is also important. In this paper, methods to determine the in-duct acoustic source data including also the non-plane waves are discussed. The low and high frequency in-duct characteristics of a test engine exhaust system are obtained and combined. The combined source data is useful when designing the components of the exhaust system, for example
Original languageEnglish
Title of host publicationProceedings of BNAM 2014
Place of PublicationTallinn
Pages528 - 533
Publication statusPublished - 2014
MoE publication typeB3 Non-refereed article in conference proceedings
EventBaltic-Nordic Acoustic Meeting, BNAM 2014 - Tallinn, Estonia
Duration: 2 Jun 20144 Jun 2014

Conference

ConferenceBaltic-Nordic Acoustic Meeting, BNAM 2014
Abbreviated titleBNAM 2014
CountryEstonia
CityTallinn
Period2/06/144/06/14

Fingerprint

exhaust systems
ducts
engines
acoustics
sound pressure
acoustic ducts
engine tests
fluids
pressure measurement
discontinuity
plane waves
turbulence

Keywords

  • acoustic source
  • IC-engine
  • exhaust system

Cite this

Hynninen, A., & Åbom, M. (2014). On acoustic in-duct characterization of medium speed IC-engine exhaust system. In Proceedings of BNAM 2014 (pp. 528 - 533). Tallinn.
Hynninen, Antti ; Åbom, Mats. / On acoustic in-duct characterization of medium speed IC-engine exhaust system. Proceedings of BNAM 2014. Tallinn, 2014. pp. 528 - 533
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Hynninen, A & Åbom, M 2014, On acoustic in-duct characterization of medium speed IC-engine exhaust system. in Proceedings of BNAM 2014. Tallinn, pp. 528 - 533, Baltic-Nordic Acoustic Meeting, BNAM 2014, Tallinn, Estonia, 2/06/14.

On acoustic in-duct characterization of medium speed IC-engine exhaust system. / Hynninen, Antti; Åbom, Mats.

Proceedings of BNAM 2014. Tallinn, 2014. p. 528 - 533.

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

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Hynninen A, Åbom M. On acoustic in-duct characterization of medium speed IC-engine exhaust system. In Proceedings of BNAM 2014. Tallinn. 2014. p. 528 - 533