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Impedance of SDOF perforated liners at high temperatures
KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
KTH, Superseded Departments, Aeronautical and Vehicle Engineering.ORCID iD: 0000-0002-8474-8563
KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
2004 (English)In: Collection of Technical Papers: 10th AIAA/CEAS Aeroacoustics Conference, 2004, Vol. 1, 505-519 p.Conference paper (Refereed)
Abstract [en]

Perforates are widely used to attenuate sound waves propagating inside a duct or enclosure. They are often found in a high temperature environment; e.g. car exhaust mufflers, exhaust ducts of aircraft jet engines, and inside combustion chambers of gas turbines. Several studies have been conducted to develop impedance models, including the effect of different configurations and flow conditions. Nevertheless, little has been published on the effect of high temperature and temperature gradients across the liner on the impedance. In this paper, the impedance of different orifices was measured at different temperatures and incident sound pressure levels. The results show that the effect of temperature gradients has to be considered during measurements and modeling. It was also found that the temperature effect on the impedance can be predicted quite well by changing the fluid properties (density, viscosity and speed of sound). If a thin sheet of porous material is added to the perforate top sheet, which is not uncommon in practice, this combination may exhibit additional high temperature effects caused for instance by structural effects in the porous material.

Place, publisher, year, edition, pages
2004. Vol. 1, 505-519 p.
Keyword [en]
Acoustic noise, Acoustic wave propagation, Aircraft engines, Aviation, Degrees of freedom (mechanics), Flow of fluids, High temperature effects, Porous materials, Pressure effects, Thermal gradients, Acoustic pressure, Aircraft jet engines, Fluid properties, Sound pressure, Acoustic impedance
National Category
Engineering and Technology
URN: urn:nbn:se:kth:diva-61834ScopusID: 2-s2.0-19644395359ISBN: 1563477130OAI: diva2:479735
Collection of Technical Papers - 10th AIAA/CEAS Aeroacoustics Conference. Manchester. 10 May 2004 - 12 May 2004

QC 20120125

Available from: 2012-01-18 Created: 2012-01-18 Last updated: 2016-09-02Bibliographically approved

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Elnady, TamerBodén, HansKontio, Timo
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