Influence of blade vibrations on aerodynamic performance of axial compressor in gas turbine: Direct numerical simulation

Erfanian Nakhchi Toosi, Mahdi, Win Naung, Shine and Rahmati, Mohammad (2022) Influence of blade vibrations on aerodynamic performance of axial compressor in gas turbine: Direct numerical simulation. Energy, 242. p. 122988. ISSN 0360-5442 (In Press)

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Official URL: https://doi.org/10.1016/j.energy.2021.122988

Abstract

Flutter instability because of the blade vibrations is a major problem in axial compressor cascades. This paper investigates the effects of blade oscillations on aerodynamic performance and turbulent flow characteristics of modern gas-turbine compressors. Highly accurate direct numerical simulations (DNS) are performed based on the spectral-hp element method to predict the flow instabilities, pressure fluctuations and vortex generation on the surface of the compressor blades by considering all complex physical parameters at different vibration frequencies (0 < f < 8.28 Hz). The main novelty of this study is to consider the aeroelastic vibrations of the compressor blades in DNS analysis. The novel proposed method enables the detailed analysis of complex structure fluid interactions, which cannot be obtained using other methods such as RANS models. The simulations revealed that the blade oscillations have a huge impact on the vortex generation and laminar separation bubble on the suction side of the blade. Moreover, the amplitude of unsteady pressure distribution is greater at 90% span, with the phage angle deviating between 100° and 350°. Strong fluctuations are observed at the centre of the wake region of the vibrating blade cascade. These fluctuations are activated by the flow disturbances resulting from the blade oscillation. Moreover, intense pressure fluctuations happen in the wake region of the oscillating compressor blade compared with the stationary one. The separating point occurred 8.28% sooner on the suction surface of the vibrating blade with k = 0.4 (Xsep/C = 0.288) compared to the stationary blade with Xsep/C = 0.314.

Item Type: Article
Additional Information: Funding information: The authors would like to acknowledge the financial support received from the Engineering Physics and Science Research Council of the UK (EPSRC EP/R010633/1).
Uncontrolled Keywords: Blade oscillations, Compressor, DNS, Spectral-hp element, Transient flow
Subjects: H300 Mechanical Engineering
H800 Chemical, Process and Energy Engineering
Department: Faculties > Engineering and Environment > Mechanical and Construction Engineering
Depositing User: Elena Carlaw
Date Deposited: 22 Dec 2021 12:57
Last Modified: 04 Jan 2022 16:15
URI: http://nrl.northumbria.ac.uk/id/eprint/48037

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