A modified Wells turbine for wave energy conversion
TL;DR: In this paper, the rotor blade pitch was set asymmetrically at a positive pitch to achieve a higher mean efficiency in a wave cycle and the performance characteristics of a turbine with different blade setting angles in steady flow were found by experimentation.
About: This article is published in Renewable Energy.The article was published on 2003-01-01. It has received 84 citations till now. The article focuses on the topics: Oscillating Water Column & Wells turbine.
Citations
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TL;DR: In this paper, the authors investigated the effect of the angle of the slot angle on the entropy generation features around the turbine blade and the aerodynamics noise emission from the turbine airfoil during the normal operation.
19 citations
TL;DR: In this article, a bend-free rectangular cross-section OWC device was designed and constructed for studying the effect of inclination on the flow characteristics inside the device, where the inclination is meant to reduce reflection of waves and induce higher velocities in the turbine section.
18 citations
01 Jan 2016
TL;DR: In this paper, the authors proposed a controller scheme to maximize the turbine output power and thereby improve the efficiency in oscillating water column (OWC) wave power plant equipped with Wells turbine and doubly fed induction generator (DFIG), which is based on flow coefficient estimation and controller design for tracking of rotational speed.
Abstract: This paper presents controller scheme to maximize the turbine output power and thereby improve the efficiency in oscillating water column (OWC) wave power plant equipped with Wells turbine and doubly fed induction generator (DFIG). The scheme is based on flow coefficient estimation and controller design for tracking of rotational speed. Initially, a linear reference tracking (LRT) approach is applied to achieve the maximized output power by establishing a linear relationship between reference rotational speed and input pressure drop. This follows implementation of fuzzy theory based maximum power point tracking (FMPPT) approach to provide the optimal speed reference. Then, a backstepping (BS) controller is designed to track reference rotational speed of DFIG so as to improve the output power. The BS controller is derived using Lyapunov stability theorem which ensures the stability of the overall closed loop system. The advantages of the proposed control scheme over conventional PI control and the uncontrolled system is demonstrated for regular waves and irregular waves. Finally, the FMPPT-BS control approach has been validated with JONSWAP irregular wave model.
18 citations
TL;DR: In this article, the interaction between regular water waves and the oscillating water column (OWC) geometry is presented in a numerical wave tank, with the commercial CFD code Fluent, where the dynamic mesh feature and the VOF Model are used for wave generation and the water-air interaction, respectively.
Abstract: The interaction between regular water waves and the oscillating water column (OWC) geometry is presented in this work. The OWC has a vertical cylindrical geometry, with walls of negligible thickness. Water waves are generated in a numerical wave tank, with the commercial CFD code Fluent, where the dynamic mesh feature and the VOF Model is used for wave generation and the water-air interaction, respectively. The flow is assumed to be viscous, unsteady and incompressible for the numerical model. To focus on the flow inside, 3D, single phase modelling of the OWC device itself is handled by adopting a piston-like pumping flow, using the free surface elevation data found in the former model as an input. To validate the results, a simplified theoretical model of a wave energy converter, namely the Japanese multi- OWC barge Kaimei is used. The theoretical model is based on the theory of a compressible air flow where the free surface elevation is assumed to be one dimensional.
18 citations
Additional excerpts
...[10] focused on the energy conversion stage of an OWC regarding Wells turbines and modifications related to the airflow velocities....
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TL;DR: In this article, an entropy generation analysis of isothermal flow through a monoplane Wells turbine was performed by solving the steady, incompressible, and three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations with RNG k à " turbulence model in a noninertial reference frame rotating with the turbine rotor rotor.
15 citations
Cites background from "A modified Wells turbine for wave e..."
...And, because of an extremely small output power, there is no practical interest in the operating range below 6 degrees [35-38]....
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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
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
01 Jan 2002
TL;DR: The Mighty Whale is a floating wave power device based on the Oscillating Water Column (OWC) principle, which converts wave energy into electric energy, and produces a relatively calm sea area behind.
Abstract: Mighty Whale is a floating wave power device based on the Oscillating Water Column (OWC) principle. It converts wave energy into electric energy, and produces a relatively calm sea area behind. The open sea tests were begun in September 1998 in Gokasho Bay, Nansei Town, Mie Prefecture. Measurements collected since then include performance data in typhoon seasons. This paper presents the measurements of wave energy absorption, floating body motion, and wave height dissipation. It is expected that these results will be useful in the design of offshore wave power devices in the future.
78 citations
01 Jan 2000
TL;DR: The Mighty Whale as mentioned in this paper was used for open sea tests to investigate the use of wave energy for power generation in Mie Prefecture, Japan, and the results of the tests were summarized in a recent paper.
Abstract: JAMSTEC completed the construction of the prototype device Mighty Whale by May 1998 for open sea tests to investigate practical use of wave energy. Following construction, the prototype was towed to the test location near the mouth of Gokasho Bay in Mie Prefecture. The open sea tests were begun in September 1998, after final positioning and mooring operations were completed. The tests are expected to continue for approximately 2 years. This paper presents an overview of the open sea tests, and summarizes the characteristics of power generation based on the results so far.
59 citations
Journal Article•
TL;DR: In this paper, the performance of the impulse turbine with fixed guide vanes was compared with that of the Wells turbine with a fixed guide vane, and it was shown that the running and starting characteristics of the latter were superior to those of the former under irregular wave conditions.
Abstract: The objective of this paper is to clarify the performance of impulse turbine with fixed guide vanes and to compare it with that of Wells turbine with guide vanes. As a result, a suitable choice of the design factors for the impulse turbine was shown for the inlet angle of rotor blade and the shape of guide vane. Furthermore, it was found that the running and starting characteristics of the impulse turbine were superior to those of the Wells turbine under irregular wave condition.
56 citations