Single and multiple circumferential casing groove for stall margin improvement in a transonic axial compressor

Mustaffa, A F and Kanjirakkad, V (2020) Single and multiple circumferential casing groove for stall margin improvement in a transonic axial compressor. ASME 2020 Turbo Expo, Virtual Conference, 21-25 September 2020. Published in: Proceedings of the ASME Turbo Expo 2020. 2A aGT2020-14974. ASME ISBN 9780791884065

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The stability limit of a tip-stalling axial compressor is sensitive to the magnitude of the near casing blockage. In transonic compressors, the presence of the passage shock could be a major cause for the blockage. Identification and elimination of this blockage could be key to improving the stability limit of the compressor. In this paper, using numerical simulation, the near casing blockage within the transonic rotor, NASA Rotor 37, is quantified using a blockage parameter. For a smooth casing, the blockage at conditions near stall has been found to be maximum at about 20% of the tip axial chord downstream of the tip leading edge. This maximum blockage location is found to be consistent with the location of the passage shock-tip leakage vortex interaction. A datum single casing groove design that minimises the peak blockage is found through an optimisation approach. The stall margin improvement of the datum casing groove is about 0.6% with negligible efficiency penalty. Furthermore, the location of the casing groove is varied upstream and downstream of the datum location. It is shown that the stability limit of the compressor is best improved when the blockage is reduced upstream of the peak blockage location. The paper also discusses the prospects of a multi-groove casing configuration.

Item Type: Conference Proceedings
Keywords: Axial Compressor, Transonic, Stall Margin, Blockage, Optimisation
Schools and Departments: School of Engineering and Informatics > Engineering and Design
Research Centres and Groups: Thermo-Fluid Mechanics Research Centre
Subjects: T Technology > TJ Mechanical engineering and machinery > TJ0266 Turbines. Turbomachines (General)
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Depositing User: Vasudevan Kanjirakkad
Date Deposited: 28 Sep 2020 13:09
Last Modified: 29 Sep 2021 08:43

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