Phased array beamforming to identify broadband noise sources in the interstage section of a turbofan engine

Conference paper (2019)

Authors

Harry Brouwer Royal Netherlands Aerospace Centre NLR
P. Sijtsma PSA3: Pieter Sijtsma Advanced AeroAcoustics
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Published Date

2019

Language

English

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Abstract

This paper proposes the enhancement of a previously developed method for beamforming in engine ducts, which enables phased array beamforming in the interstage section of a turbofan engine. The enhanced method features the use of tailored Green’s functions, to deal with the annular geometry and the non-uniform (swirling) flow in this part of the engine duct. A complicating factor is the occurrence of resonant acoustic modes, when there is no acoustic lining. The paper describes the computation of the tailored Green’s functions and how resonant modes can be subtracted. The use of the method is firstly demonstrated by application to simulated sources, and is subsequently applied to test data. At the moment there is no other information on the sources that could be used to validate the method. The only indication that the method is working well is that it should find the correct number of rotating fan blades in the beamforming plots. This is indeed the case, but only in a small fraction of the results.