Effects of ported shroud casing treatment on the acoustic and flow behaviour of a centrifugal compressor

Sidharath Sharma, Jorge García-Tíscar, John Allport, Simon Barrans, Keith Nickson

Research output: Contribution to journalArticle

Abstract

Centrifugal turbomachines of smaller sizes operating at higher speeds have become pervasive due to the increased specific power and reliability achieved by improvements in manufacturing, materials and computational methods.
The presence of these small turbomachines, specifically compressors, in helicopters, unmanned aerial vehicles (UAVs), auxiliary power units (APUs), turbochargers and micro gas turbines necessitates superior aerodynamic
performance over a broad operational range which is widely achieved by ported shroud casing designs. In addition to aerodynamic performance, acoustic emissions have become a critical aspect of design for these small centrifugal
compressors due to high operational speeds. Furthermore, the literature on the acoustic effects of the casing treatment is rather limited. Therefore, the impact of ported shroud casing treatment on the acoustic and flow features of the compressor operating at the design and near surge conditions have been quantified by numerically modelling the open and blocked configuration of the compressors. Upon comparing with experimental results, the
numerical spectra are shown to capture the differences between the two configurations at the investigated operating points with reasonable accuracy. Although the casing treatment is generally seen to decrease the overall acoustic
emission of the compressor at both operating conditions, increased propagation of tonal content in the direction upstream to the impeller is observed, particularly for design operation. Broadband characteristics in the lower and
medium frequency regions usually associated with near surge operation including ‘whoosh’ noise are observed to be alleviated by the ported shroud casing treatment.
Original languageEnglish
JournalInternational Journal of Engine Research
Early online date7 Oct 2019
DOIs
Publication statusE-pub ahead of print - 7 Oct 2019

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Centrifugal compressors
Compressors
Acoustics
Unmanned aerial vehicles (UAV)
Acoustic emissions
Computational methods
Helicopters
Gas turbines
Aerodynamics

Cite this

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title = "Effects of ported shroud casing treatment on the acoustic and flow behaviour of a centrifugal compressor",
abstract = "Centrifugal turbomachines of smaller sizes operating at higher speeds have become pervasive due to the increased specific power and reliability achieved by improvements in manufacturing, materials and computational methods.The presence of these small turbomachines, specifically compressors, in helicopters, unmanned aerial vehicles (UAVs), auxiliary power units (APUs), turbochargers and micro gas turbines necessitates superior aerodynamicperformance over a broad operational range which is widely achieved by ported shroud casing designs. In addition to aerodynamic performance, acoustic emissions have become a critical aspect of design for these small centrifugalcompressors due to high operational speeds. Furthermore, the literature on the acoustic effects of the casing treatment is rather limited. Therefore, the impact of ported shroud casing treatment on the acoustic and flow features of the compressor operating at the design and near surge conditions have been quantified by numerically modelling the open and blocked configuration of the compressors. Upon comparing with experimental results, thenumerical spectra are shown to capture the differences between the two configurations at the investigated operating points with reasonable accuracy. Although the casing treatment is generally seen to decrease the overall acousticemission of the compressor at both operating conditions, increased propagation of tonal content in the direction upstream to the impeller is observed, particularly for design operation. Broadband characteristics in the lower andmedium frequency regions usually associated with near surge operation including ‘whoosh’ noise are observed to be alleviated by the ported shroud casing treatment.",
keywords = "Compressor noise, stress blended eddy simulation, Ported Shroud, computational fluid dynamics, aeroacoustics",
author = "Sidharath Sharma and Jorge Garc{\'i}a-T{\'i}scar and John Allport and Simon Barrans and Keith Nickson",
year = "2019",
month = "10",
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doi = "10.1177/1468087419880431",
language = "English",
journal = "International Journal of Engine Research",
issn = "1468-0874",
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T1 - Effects of ported shroud casing treatment on the acoustic and flow behaviour of a centrifugal compressor

AU - Sharma, Sidharath

AU - García-Tíscar, Jorge

AU - Allport, John

AU - Barrans, Simon

AU - Nickson, Keith

PY - 2019/10/7

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N2 - Centrifugal turbomachines of smaller sizes operating at higher speeds have become pervasive due to the increased specific power and reliability achieved by improvements in manufacturing, materials and computational methods.The presence of these small turbomachines, specifically compressors, in helicopters, unmanned aerial vehicles (UAVs), auxiliary power units (APUs), turbochargers and micro gas turbines necessitates superior aerodynamicperformance over a broad operational range which is widely achieved by ported shroud casing designs. In addition to aerodynamic performance, acoustic emissions have become a critical aspect of design for these small centrifugalcompressors due to high operational speeds. Furthermore, the literature on the acoustic effects of the casing treatment is rather limited. Therefore, the impact of ported shroud casing treatment on the acoustic and flow features of the compressor operating at the design and near surge conditions have been quantified by numerically modelling the open and blocked configuration of the compressors. Upon comparing with experimental results, thenumerical spectra are shown to capture the differences between the two configurations at the investigated operating points with reasonable accuracy. Although the casing treatment is generally seen to decrease the overall acousticemission of the compressor at both operating conditions, increased propagation of tonal content in the direction upstream to the impeller is observed, particularly for design operation. Broadband characteristics in the lower andmedium frequency regions usually associated with near surge operation including ‘whoosh’ noise are observed to be alleviated by the ported shroud casing treatment.

AB - Centrifugal turbomachines of smaller sizes operating at higher speeds have become pervasive due to the increased specific power and reliability achieved by improvements in manufacturing, materials and computational methods.The presence of these small turbomachines, specifically compressors, in helicopters, unmanned aerial vehicles (UAVs), auxiliary power units (APUs), turbochargers and micro gas turbines necessitates superior aerodynamicperformance over a broad operational range which is widely achieved by ported shroud casing designs. In addition to aerodynamic performance, acoustic emissions have become a critical aspect of design for these small centrifugalcompressors due to high operational speeds. Furthermore, the literature on the acoustic effects of the casing treatment is rather limited. Therefore, the impact of ported shroud casing treatment on the acoustic and flow features of the compressor operating at the design and near surge conditions have been quantified by numerically modelling the open and blocked configuration of the compressors. Upon comparing with experimental results, thenumerical spectra are shown to capture the differences between the two configurations at the investigated operating points with reasonable accuracy. Although the casing treatment is generally seen to decrease the overall acousticemission of the compressor at both operating conditions, increased propagation of tonal content in the direction upstream to the impeller is observed, particularly for design operation. Broadband characteristics in the lower andmedium frequency regions usually associated with near surge operation including ‘whoosh’ noise are observed to be alleviated by the ported shroud casing treatment.

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