Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.639067
Title: Investigation into the suppression of acoustic resonances
Author: Smith, N. H. S.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1991
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Abstract:
As aero-engine manufacturers strive for ever greater performance, phenomena associated with the inherent unsteadiness within the flow of the compression system, cause aero-manufacturers severe headaches in the eternal pursuit for improved performance. The commonly known unsteady or aero-elastic/aero-acoustic problems such as rotating stall cells, flutter, surge, have an additional member; namely acoustic resonances. Although the phenomenon of acoustic resonances have only recently been associated with experimental research compressors, the phenomenon is yet another pernickety problem that needs to be controlled within compressors. This thesis presents a solution for eliminating acoustic resonances from axial flow compressors. The research work carried out between the years 1986-1989 dealt with experimental tests in which an acoustic wall treatment was used for suppressing the excitation mechanism through which an acoustic resonance is generated. Experimental tests were performed with a wall treatment positioned in the outside wall of a single stage axial compressor, the treatment was optimised for suppressing acoustic modes known to exist in the rig. The tests illustrated a tuned acoustic treatment consisting of a honeycomb type structure sandwiched between a perforated facing sheet and a rigid backing sheet, can reduce the sound pressure level of the acoustic modes to below noise levels associated with blade passing effects. Theoretical work is also presented in which an acoustic resonance in an annulus is modelled with and without an acoustic treatment present.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.639067  DOI: Not available
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