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Aircraft turbine combustion noise processing

Aircraft turbine combustion noise processing
Aircraft turbine combustion noise processing
Appraisal of the noise produced at the combustion stage in a jet engine is becoming more important, as fan and jet noise have been significantly reduced over many years. Therefore, combustion noise is contributing more to overall noise, especially at low jet velocities. Environmental regulations stipulate that gas emissions from a jet engine should be reduced. Thus, new techniques have been introduced in their operation, especially concerning the combustion process. Accordingly, there is a need for improved processing methods in order to extract combustion noise from other sources in new build engines.

A novel processing technique to extract turbofan engine combustion noise called 3S-Array is presented. It has been developed using a multiple coherence technique with data acquired in the in-duct and external sound fields of a jet engine. In-duct sensors are located in the combustion chamber and in the nozzle of the engine, and external data is acquired using an array of microphones. A beamformed signal focused on the nozzle of the engine is generated with the data from the external array. Jet noise and in influences of the room on the array output are reduced using this focusing technique, which is referred to as Focused Beamformed Output (FBO).

Results show that using this new 3S-Array technique with two of the in-duct sensors and the focused beamformed signal as the third one, provides a better estimator of combustion noise than the 3-signal coherence technique alone, or the Coherence-Output Power Spectra (COP), both of which are reported in the literature as methods for the extraction of combustion noise from the radiated noise spectrum.
University of Southampton
Rodriguez Garcia, Paul
cbe9b5ec-bc9d-46cb-a732-1d1aa4cc54d3
Rodriguez Garcia, Paul
cbe9b5ec-bc9d-46cb-a732-1d1aa4cc54d3
Holland, Keith
90dd842b-e3c8-45bb-865e-3e7da77ec703

Rodriguez Garcia, Paul (2016) Aircraft turbine combustion noise processing. University of Southampton, Doctoral Thesis, 223pp.

Record type: Thesis (Doctoral)

Abstract

Appraisal of the noise produced at the combustion stage in a jet engine is becoming more important, as fan and jet noise have been significantly reduced over many years. Therefore, combustion noise is contributing more to overall noise, especially at low jet velocities. Environmental regulations stipulate that gas emissions from a jet engine should be reduced. Thus, new techniques have been introduced in their operation, especially concerning the combustion process. Accordingly, there is a need for improved processing methods in order to extract combustion noise from other sources in new build engines.

A novel processing technique to extract turbofan engine combustion noise called 3S-Array is presented. It has been developed using a multiple coherence technique with data acquired in the in-duct and external sound fields of a jet engine. In-duct sensors are located in the combustion chamber and in the nozzle of the engine, and external data is acquired using an array of microphones. A beamformed signal focused on the nozzle of the engine is generated with the data from the external array. Jet noise and in influences of the room on the array output are reduced using this focusing technique, which is referred to as Focused Beamformed Output (FBO).

Results show that using this new 3S-Array technique with two of the in-duct sensors and the focused beamformed signal as the third one, provides a better estimator of combustion noise than the 3-signal coherence technique alone, or the Coherence-Output Power Spectra (COP), both of which are reported in the literature as methods for the extraction of combustion noise from the radiated noise spectrum.

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Final e-thesis for e-prints RODRIGUEZ GARCIA 23734841 - Version of Record
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Published date: October 2016

Identifiers

Local EPrints ID: 413857
URI: http://eprints.soton.ac.uk/id/eprint/413857
PURE UUID: 1bf9b6da-a72c-4312-967d-5ec855e022e2
ORCID for Keith Holland: ORCID iD orcid.org/0000-0001-7439-2375

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Date deposited: 07 Sep 2017 16:34
Last modified: 14 Mar 2019 01:54

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