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Mechanical engineering

Centrifugal Compressor Instability and the Reverse Propagation Mechanism in Diffusers

Strategic Insights

— 1 min read

New research on mechanical engineering and machinery has highlighted the crucial concern of aerodynamic instabilities in centrifugal compressors at low flow rates. According to a study published in the Journal of Applied Fluid Mechanics, researchers from the State Key Laboratory investigated the aerodynamic behavior of a standard centrifugal compressor through numerical simulations in both steady and unsteady full-annulus states. The study focused on the stability of diffusers and the reverse propagation mechanism in centrifugal compressors.

Key Takeaways:

  • The research found that as the flow rate decreases and the flow shifts downstream in the full-cycle model, the non-uniformity of the Mach number in the circumferential direction near the blockage region increases from 8.13% to 25.52%.
  • Under the design condition, the circumferential non-uniformity rises from 15.18% to 24.12%.
  • The centrifugal impeller exhibits rotational instabilities with a disturbance frequency of 1304.61 Hz, corresponding to 23.95% of the blade passing frequency.
  • The study provides fresh insights into unsteady flow characteristics in centrifugal compressors and offers practical guidelines for enhancing the operational stability of microturbine units.
  • The research was conducted by a team of researchers from the State Key Laboratory, including Y. Ping, M. Wang, X. Zhang, K. Bai, F. Qu, Z. Tao, and C. Wang.

Statistics:

  • The non-uniformity of the Mach number in the circumferential direction near the blockage region increases from 8.13% to 25.52% as the flow rate decreases and the flow shifts downstream in the full-cycle model.
  • Under the design condition, the circumferential non-uniformity rises from 15.18% to 24.12%.
  • The centrifugal impeller exhibits rotational instabilities with a disturbance frequency of 1304.61 Hz, corresponding to 23.95% of the blade passing frequency.
  • The study provides practical guidelines for enhancing the operational stability of microturbine units.

Sources:

  • Centrifugal Compressor Instability and the Reverse Propagation Mechanism in Diffusers. Journal of Applied Fluid Mechanics, 2025,18(12):3101-3115. (Journal of Applied Fluid Mechanics - http://jafmonline.net).
  • The publisher for Journal of Applied Fluid Mechanics is Isfahan University of Technology.
  • A free version of this journal article is available at https://doi-org.sdpl.idm.oclc.org/10.47176/jafm.18.12.3593.

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