Impact of Impeller Casing Treatment on the Acoustics of a Small High Speed Centrifugal Compressor

Sidharath Sharma, Jorge García-Tíscar, John Allport, Martyn Jupp, Ambrose Nickson

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

4 Citations (Scopus)


Ported shroud casing treatment is widely used to delay the onset of surge and thereby enhancing the aerodynamic stability of a centrifugal compressor by recirculating the low momentum fluid in the blade passage. Performance losses associated with the use of recirculation casing treatment are well established in the literature and this is an area of active research. The other, less researched aspect of the casing treatment is its impact on the acoustics of the compressor. This work investigates the impact of ported shroud casing treatment on the acoustic characteristics of the compressor. The flow in two compressor configurations viz. with and without casing treatment operating at the design operating conditions of an iso-speed line are numerically modelled and validated with experimental data from gas stand measurements. The pressure fluctuations calculated as the flow solution are used to compute the spectral signatures at multiple locations to investigate the acoustic phenomenon associated with each configuration. Propagation of the frequency content through the ducts has been estimated with the aid of method of characteristics to enhance the content coming from the compressor. Expected tonal aerodynamic noise sources such as monopole (buzz-saw tones) and dipole (Blade Pass Frequency) are clearly identified in the acoustic spectra of the two configurations. The comparison of two configurations shows higher overall levels and tonal content in the case of a compressor with ported shroud operating at design conditions due to the presence of ‘mid-tones’.
Original languageEnglish
Title of host publicationASME Turbo Expo 2018
Subtitle of host publicationTurbomachinery Technical Conference and Exposition
PublisherAmerican Society of Mechanical Engineers (ASME)
Volume2B: Turbomachinery
ISBN (Electronic)9780791851005
Publication statusPublished - Jun 2018
EventAmerican Society of Mechanical Engineers Turbo Expo: Turbomachinery Technical Conference & Exposition - Norway Exhibition and Convention Centre , Lillestrøm, Norway
Duration: 11 Jun 201815 Jun 2018 (Link to Conference Website )


ConferenceAmerican Society of Mechanical Engineers Turbo Expo
Internet address


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