The challenge of time-resolved flow investigation of a one-stage centrifugal compressor with a non-symmetric volute

Authors

Melanie Voges - German Aerospace Center (DLR)
Oliver Reutter - German Aerospace Center (DLR)
Alessandro Bassetti - German Aerospace Center (DLR)
Michel van Rooij - Royal Netherlands Aerospace Center (NLR)
Christian Willert - German Aerospace Center (DLR)

Abstract

In the framework of H2020 Cleansky2 project ROSSINI an industrial centrifugal compressor stage including vaneless diffuser and a non-symmetric volute is investigated with regard to the development of flow instabilities and rotating stall.Due to the complex flow path geometry of the volute a sophisticated instrumentation concept was developed allowing for combined high resolution flow field and unsteady pressure investigation. This paper is aimed at summarizing the challenges and the steps taken during rig design in terms of integrating non-intrusive, high resolution pressure measurement sensors and access for optical techniques such as time-resolved PIV and L2F to investigate unsteady flow phenomena and stall inception occurring at part speed operation. Results of the performance measurements and surge testing will be presented and compared to CFD simulations of the numerical twin of the compressor stage.A deeper understanding of flow phenomena that might be a precurser for stall inception would help to predict unstable operation already during the design phase, as today the design is commonly supported by CFD analysis providing performance data and flow information at an early stage of the design process.