Turbine blade/vane interaction noise - Acoustic mode analysis using in-duct sensor rakes

Enghardt, Lars; Tapken, Ulf; Neise, W.; Kennepohl, Fritz; Heing, K.

doi:10.2514/6.2001-2153

Cited by 49 publications

(17 citation statements)

References 2 publications

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“…Acoustic interaction between rotors is a common observation in turbomachinery noise measurements and has been discussed analytically by Cumpsty, 13 Holste & Neise 14 , Enghardt et al 15 and numerically by Nallasamy.…”

Section: Non-linear Analysismentioning

confidence: 99%

Non-linear Identification Applied to Broadband Turbomachinery Noise

Bennett

Davis

Tapken

et al. 2010

16th AIAA/CEAS Aeroacoustics Conference

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Coherence based source analysis techniques can be used to identify the contribution of broadband noise sources in the exhaust of a gas turbine and hence enable the design of noise reduction devices. However, when the broadband noise source propagates in a non-linear fashion the identified contribution using ordinary coherence methods will be inaccurate. In this paper, an analysis technique to enable the contribution of linear and non-linear mechanisms to the propagated sound to be identified is reported. An experimental rig to study the propagation of noise through a rotor/stator set-up using a vane-axial fan mounted in a duct so that non-linear interactions between a sound source and the fan could be investigated is described. The technique which is used to identify non-linear noise contributions generated by the interaction of the rotor and propagated narrowband noise is reported. The analysis techniques enabled non-linear interactions to be identified and linear and contributions to be determined.

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Section: Non-linear Analysismentioning

confidence: 99%

Non-linear Identification Applied to Broadband Turbomachinery Noise

Bennett

Davis

Tapken

et al. 2010

16th AIAA/CEAS Aeroacoustics Conference

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“…This paper examines the scenario where a fluctuating pressure is modified, in a non-linear sense, as it propagates through a rotor/stator stage. Acoustic interaction between rotors is a common observation in turbo-machinery noise measurements and has been discussed analytically by Cumpsty, 14 Holste and Neise, 15 Enghardt et al 16 and numerically by Nallasamy. 17 Energy at two different frequencies may interact to induce energy at a third.…”

Section: Non-linear Analysismentioning

confidence: 99%

Noise-Source Identification for Ducted Fan Systems

Bennett

Fitzpatrick

2008

AIAA Journal

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Coherence based source analysis techniques can be used to identify the contribution of combustion noise in the exhaust of a jet engine and hence enable the design of noise reduction devices. However, when the combustion noise propagates in a non-linear fashion the identified contribution using ordinary coherence methods will be inaccurate. In this paper, an analysis technique to enable the contribution of linear and non-linear mechanisms to the propagated sound to be identified is reported. An experimental rig to study the propagation of noise through a rotor/stator set-up using a vane-axial fan mounted in a duct so that non-linear interactions between a sound source and the fan could be investigated is described. The technique which is used to identify a non-linear tone generated by the interaction of the rotor and a propagated tone is reported. The identification procedures are then applied to data from full scale turbo-fan engine tests instrumented with pressure transducers at the combustor can and in the hot-jet pipe with microphones in the near-field. At a particular power setting, the interaction between the combustion noise and the high pressure turbine was measured in the hot jet pipe. The analysis techniques enabled non-linear interactions to be identified and linear and non-linear coherent output powers to be determined.

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“…(Moser, et al, 2009)). The theory of acoustic data analysis used in this work is well described in (Enghardt, et al, 2001) and (Enghardt, et al, 2005). In cylindrical coordinates and for a single frequency component ω the solution of the wave equation is given by a linear superposition of modal terms as can be seen in equation (4).…”

Section: Acoustic Measurements and Mode Analysismentioning

confidence: 99%

Experimental Determination of the Effectiveness of a Sound Absorbing Turbine Exit Casing

Zenz

Schönleitner

Simonassi³

et al. 2017

European Conference on Turbomachinery Fluid Dynamics and Hermodynamics

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This work presents results from experimental investigations conducted in the subsonic test turbine facility for aerodynamic, acoustic, and aeroelastic investigations at Graz University of Technology. The experiments have been performed for the acoustically relevant operating point approach under engine relevant conditions. The sound absorbing exit guide vanes of the turbine exit casing have been designed as Helmholtz resonators with a resonance frequency according to the blade passing frequency of an aero design point. In order to prove the effectiveness of that exit guide vanes acoustic measurements and modal decomposition have been performed and the sound power per azimuthal mode was calculated and compared with results of a conventional hard wall exit guide vane of aerodynamic design. It is shown that the sound power level can be reduced significantly by about 23 dB. However, the losses are increased dramatically. KEYWORDS

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Turbine blade/vane interaction noise - Acoustic mode analysis using in-duct sensor rakes

Cited by 49 publications

References 2 publications

Non-linear Identification Applied to Broadband Turbomachinery Noise

Non-linear Identification Applied to Broadband Turbomachinery Noise

Noise-Source Identification for Ducted Fan Systems

Experimental Determination of the Effectiveness of a Sound Absorbing Turbine Exit Casing

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