Hysteresis Behavior for Wave Energy Conversion Device Under Alternative Axial Flow Conditions
01 Jan 2019-pp 717-723
TL;DR: In this paper, the authors reported the characteristics of the hysteresis behavior of a Wells turbine for a wave energy conversion device under alternative axial flow conditions, and the numerical work was carried out by solving the three-dimensional unsteady Reynolds Average Navier-Stokes equations (URANS) with two-equation eddy viscosity model.
Abstract: Wells turbine is an axial flow air turbine extensively used in the oscillating water column (OWC) of ocean energy harvesting device. The turbine has low aerodynamic efficiency at higher flow rate and poor starting characteristics. In this paper, the characteristics of the hysteresis behavior of a Wells turbine for a wave energy conversion device under alternative axial flow conditions are reported. The numerical work is carried out by solving the three-dimensional unsteady Reynolds Average Navier–Stokes equations (URANS) with two-equation eddy viscosity model. It is noticed that the unsteady numerical results are associated with two hysteresis loop. In the clockwise hysteresis loop, larger flow separation can be noticed on the blade suction side due to stronger vortex while flow separation decreases due to weaker vortex during counterclockwise hysteresis loop. Also, the effect of the blade sweep and blade profile thickness on the hysteresis behavior of the wave energy conversion device are reported.
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TL;DR: In this paper, the authors introduce stall fences in the Wells turbine blade to postpone stall and widen the operating range of the turbine, where the stall fences are defined by the length, height, and thickness in percentage of blade chord length.
29 citations
References
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TL;DR: In this article, the performance of a single plane biplane Wells turbine with or without guide vanes is compared with a wave energy device based on the principle of the oscillating water-air column.
286 citations
01 Mar 1997
TL;DR: Several types of single-plane and multiplane Wells turbines are investigated and compared in this paper, where the turbines' aerodynamic losses and overall performances are presented and two successful methods of swirl energy recovery are studied in detail.
Abstract: Several types of single-plane and multiplane Wells turbines are investigated and compared. The turbines’ aerodynamic losses and overall performances are presented and two successful methods of swirl energy recovery are studied in detail. Guide vanes were fitted to a monoplane turbine whereas the rotors of a biplane turbine were contra-rotated. A double-shaft biplane turbine was also tested. The contra-rotating turbine had an operational range which was similar to that of the monoplane turbine with guide vanes, achieved a similar peak efficiency, but performed better in the post-stall region and also was found to be able to accommodate a much higher pressure-flow ratio.
154 citations
TL;DR: In this article, the authors investigated the influence of the turbine aerodynamic design on the overall plant performance, as affected by the turbine peak efficiency and the range of flow rates within which the turbine can operate efficiently.
109 citations
TL;DR: In this article, the authors provided an accurate description of the steady three-dimensional flow field in a high solidity Wells turbine to be used in an oscillatory water column (OWC) device for wave energy conversion.
99 citations
TL;DR: In this article, the performance of a Wells turbine operating under unsteady bi-directional airflow conditions was analyzed for two solidities under sinusoidal and irregular steady flow conditions based on Irish waves (Site2).
63 citations