An Evaluation of Vaneless Diffuser Modelling Methods as a Means of Improving the Off-Design Performance Prediction of Centrifugal Compressors

Charles Stuart, Stephen Spence, Dietmar Filsinger, Andre Starke, Sung In Kim, Peter Harley

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Citations (Scopus)

Abstract

An evaluation of existing 1-D vaneless diffuser design tools in the context of improving the off-design performance prediction of automotive turbocharger centrifugal compressors is described. A combination of extensive gas stand test data and single passage CFD simulations have been employed in order to permit evaluation of the different methods, allowing conclusions about the relative benefits and deficiencies of each of the different approaches to be determined. The vaneless diffuser itself has been isolated from the incumbent limitations in the accuracy of 1-D impeller modelling tools through development of a method to fully specify impeller exit conditions (in terms of mean quantities) using only standard test stand data with additional interstage static pressure measurements at the entrance to the diffuser. This method allowed a direct comparison between the test data and 1-D methods through sharing common inputs, thus achieving the aim of diffuser isolation.

Crucial to the accuracy of determining the performance of each of the vaneless diffuser configurations was the ability to quantify the presence and extent of the spanwise aerodynamic blockage present at the diffuser inlet section. A method to evaluate this critical parameter using CFD data is described herein, along with a correlation for blockage related to a new diffuser inlet flow parameter ⚡, equal to the quotient of the local flow coefficient and impeller tip speed Mach number. The resulting correlation permitted the variation of blockage with operating condition to be captured.
Original languageEnglish
Title of host publicationProceedings of ASME Turbo Expo 2015: Turbine Technical Conference and Exposition
PublisherThe American Society of Mechanical Engineers (ASME)
Number of pages13
Volume2C
ISBN (Electronic)978-0-7918-5665-9
DOIs
Publication statusPublished - Jun 2015
EventASME TURBOEXPO 2015: Turbine Technical Conference and Expositition - Palais des Congres, Montreal, Canada
Duration: 15 Jun 201519 Jun 2015

Conference

ConferenceASME TURBOEXPO 2015: Turbine Technical Conference and Expositition
CountryCanada
CityMontreal
Period15/06/201519/06/2015

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    Stuart, C., Spence, S., Filsinger, D., Starke, A., Kim, S. I., & Harley, P. (2015). An Evaluation of Vaneless Diffuser Modelling Methods as a Means of Improving the Off-Design Performance Prediction of Centrifugal Compressors. In Proceedings of ASME Turbo Expo 2015: Turbine Technical Conference and Exposition (Vol. 2C). [GT2015-42657] The American Society of Mechanical Engineers (ASME). https://doi.org/10.1115/GT2015-42657