Influence of vortex interactions on the exergy transfer and performance of OWC wells turbine

To provide deep dives about aerodynamic loss mechanisms in Wells turbines for wave energy conversion, a loss audit analysis was performed by numerical experiments in a monoplane Wells turbine with guide vanes. The interactions between the tip-leakage and leading-edge vortices during the stall proces...

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Bibliographic Details
Published in:Proceedings of the Institution of Mechanical Engineers. Part A, Journal of power and energy Journal of power and energy, 2023-09, Vol.237 (6), p.1264-1283
Main Authors: Geng, Kaihe, Yang, Ce, Zhang, Hanzhi, Zhao, Ben, Hu, Chenxing, Gao, Jianbing, Li, Yanzhao
Format: Article
Language:English
Subjects:
Aerodynamics
Blade tips
Energy conversion
Exergy
Fluid flow
Guide vanes
Identification methods
Kinetic energy
Leading edges
Leakage
Stalling
Suction
Vortices
Wave power
Wells turbines
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Summary:To provide deep dives about aerodynamic loss mechanisms in Wells turbines for wave energy conversion, a loss audit analysis was performed by numerical experiments in a monoplane Wells turbine with guide vanes. The interactions between the tip-leakage and leading-edge vortices during the stall process were captured by an improved vortex identification method, which revealed the relationship between vortex interactions and stall mechanisms by identifying coherent structures and tracking the vortex core trajectory. Finally, the influence of vortex interactions on exergy transfer was quantified. The results indicate that the lost kinetic energy and mixing losses dominate the loss generation in the Wells turbine stage under stall conditions. Under the beneficial effect of tip leakage flow, leading-edge separation first begins at the equilibrium region between the tip-leakage and leading-edge vortices. As the leading-edge vortices expand toward the blade tip, the intensified leading-edge vortex interacts with the casing suction-side corner vortex and accelerates the dissipation of the tip-leakage vortices. Consequently, the contributions of viscous irreversibilities outweigh those of shaft work, being the dominant factor in the decrease in flow exergy, leading to a decrease in exergy utilization by 38.46% from the pre-stall condition to the stall condition.
ISSN:0957-6509
2041-2967
DOI:10.1177/09576509231163390