Mode transition in a standing-wave thermoacoustic engine: a numerical study

Chen, G., Tang, L., Yu, Z. and Mace, B. (2021) Mode transition in a standing-wave thermoacoustic engine: a numerical study. Journal of Sound and Vibration, 504, 116119. (doi: 10.1016/j.jsv.2021.116119)

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This study investigates the mode transition phenomenon in a standing-wave thermoacoustic engine (TAE) by means of computational fluid dynamics (CFD). Firstly, the steady-state responses of the TAE at selected temperature ratios are examined via continuous wavelet transform. The bifurcation diagram and spectral map indicate that, as the temperature ratio increases, the TAE experiences a series of bifurcations, through which first-mode periodic oscillations, quasiperiodic oscillations and second-mode periodic oscillations occur. Secondly, the TAE performances in the initial decay/build-up, nonlinear saturation and steady states are studied. The onset of the first and/or second acoustic mode is identified via dynamic mode decomposition. The oscillation frequencies and growth/attenuation rates from CFD agree well with those from the reduced-order network model. Nonlinear mode competition takes place during saturation in which the growth of one acoustic mode is affected or even totally inhibited by the growth of the other. At steady state, periodic oscillations exhibit a closed loop in the phase space whilst quasiperiodic oscillations generate a torus. The time-averaged acoustic energy density, acoustic intensity and efficiency increase with increasing temperature ratio. Finally, parametric studies are conducted to investigate the effects of the gap between stack plates and stack position on mode transition. It is found that the TAE will exhibit second-mode oscillations if the stack is near the closed end or the gap is small. Results in this study indicate that mode transition could become a novel approach to match the TAE with external loads for higher electric power outputs.

Item Type:Articles
Additional Information:The authors are grateful for the financial support from China Scholarship Council (no. 201608630046) and the Universitas 21 Doctoral Student Mobility Scholarship from the University of Auckland.
Glasgow Author(s) Enlighten ID:Yu, Professor Zhibin and CHEN, GENG
Creator Roles:
Chen, G.Conceptualization, Methodology, Software, Validation, Formal analysis, Writing – original draft
Yu, Z.Writing – review and editing, Supervision
Authors: Chen, G., Tang, L., Yu, Z., and Mace, B.
College/School:College of Science and Engineering
College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Journal of Sound and Vibration
ISSN (Online):1095-8568
Published Online:08 April 2021
Copyright Holders:Copyright © 2021 Elsevier Ltd.
First Published:First published in Journal of Sound and Vibration 504: 116119
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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