The unsteady behavior of diffuser stall in a centrifugal compressor with vaneless diffuser

Hiroshi Miida, Kenta Tajima, Nobumichi Fujisawa, Yutaka Ohta

研究成果: Conference contribution

1 被引用数 (Scopus)

抄録

The unsteady diffuser stall behavior in a centrifugal compressor with a vaneless diffuser was investigated by experimental and computational analyses. The diffuser stall generated as the mass flow rate decreased. The diffuser stall cell rotated at 25-30 % of the impeller rotational speed, with diffuser stall fluctuations observed at 180° from the cutoff. The diffuser stall fluctuation magnitude gradually increased near the cutoff. Based on diffuser inlet velocity measurements, the diffuser stall fluctuations generated near both the shroud and hub sides, and the diffuser stall appeared at 180° and 240° from the cutoff. According to the CFD analysis, the mass flow fluctuations at the diffuser exit showed a low mass flow region, rotating at approximately 25% of the impeller rotational speed. They began at 180° from the cutoff and developed as this region approached the cutoff. Therefore, the diffuser stall could be simulated by CFD analysis. First, the diffuser stall cell originated at 180° from the cutoff by interaction with boundary separation and impeller discharge vortex. Then, the diffuser stall cell further developed by boundary separation accumulation and the induced low velocity area, located at the stall cell center. The low velocity region formed a blockage across the diffuser passage span. The diffuser stall cell expanded in the impeller rotational direction due to boundary separation caused by a positive flow angle. Finally, the diffuser stall cell vanished when it passed the cutoff, because mass flow recovery occurred.

本文言語English
ホスト出版物のタイトルFluid Applications and Systems; Fluid Measurement and Instrumentation
出版社American Society of Mechanical Engineers (ASME)
ISBN(電子版)9780791883716
DOI
出版ステータスPublished - 2020
イベントASME 2020 Fluids Engineering Division Summer Meeting, FEDSM 2020, collocated with the ASME 2020 Heat Transfer Summer Conference and the ASME 2020 18th International Conference on Nanochannels, Microchannels, and Minichannels - Virtual, Online
継続期間: 2020 7 132020 7 15

出版物シリーズ

名前American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FEDSM
1
ISSN(印刷版)0888-8116

Conference

ConferenceASME 2020 Fluids Engineering Division Summer Meeting, FEDSM 2020, collocated with the ASME 2020 Heat Transfer Summer Conference and the ASME 2020 18th International Conference on Nanochannels, Microchannels, and Minichannels
CityVirtual, Online
Period20/7/1320/7/15

ASJC Scopus subject areas

  • 機械工学

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