The Development and Testing of a Wave-Activated Navigation Buoy With a Wells Turbine

1985 ◽  
Vol 107 (2) ◽  
pp. 268-273 ◽  
Author(s):  
T. J. T. Whittaker ◽  
F. A. McPeake ◽  
A. G. Barr
Keyword(s):  
Water Column ◽  
Peak Performance ◽  
Optimum Level ◽  
Wells Turbine ◽  
Turbine Generator ◽  
Ongoing Research ◽  
Air Turbine ◽  
Hydrodynamic Response ◽  
Current Design ◽  
Heave Motion

This paper presents and discusses the results of the first stage of an ongoing research program to improve the design of wave powered navigation aids using the oscillating water column principle. Wave tank testing has shown that the heave motion of current tail tube buoys is the predominant feature of the hydrodynamic response. A Wells self rectifying air turbine, coupled to a 100-W generator which produces an optimum level of damping to the water column for peak performance, has been designed and tested. It has been concluded from preliminary sea trails that a simple, efficient, reliable, turbine-generator has been developed to meet the requirements of the current design of navigation buoy. However there is considerable scope for improving the hydrodynamic design of wave activated buoys.

A Study on the Effects of Blade Profile and Non-Uniform Tip Clearance of the Wells Turbine

2008 ◽  
Author(s):  
Manabu Takao ◽  
Toshiaki Setoguchi ◽  
Shuichi Nagata ◽  
Kazutaka Toyota
Keyword(s):  
Water Column ◽  
Wave Energy ◽  
Flow Condition ◽  
Rotor Blade ◽  
Tip Clearance ◽  
Blade Profile ◽  
Wells Turbine ◽  
Energy Devices ◽  
Air Turbine ◽  
Air Column

Several of wave energy devices being studied under many wave energy programs in the United Kingdom, Japan, Portugal, India and other countries make use of the principle of an oscillating water column (OWC). In such wave energy devices, a water column which oscillates due to wave motion is used to drive an oscillating air column which is converted into mechanical energy. The energy conversion from the oscillating air column can be achieved by using a self-rectifying air turbine. Wells turbine is a self-rectifying air turbine which is expected to be widely used in wave energy devices with OWC. There are many reports which describe the performance of Wells turbine both at starting and running characteristics. According to these results, Wells turbine has inherent disadvantages: lower efficiency, poorer starting and higher noise level in comparison with conventional turbines. In order to enhance the performance of Wells turbine, some rotor blade profiles have been recommended by various researchers. The aim of this study is to investigate the effect of rotor blade profile on the performance of Wells turbine. In the study, four kinds of blade profile were selected and tested by model testing under steady flow condition. The types of blade profile are as follows: NACA0020; NACA0015; modified NACA0015; and modified Eppler472. The experimental investigations have been performed by use of test section with a casing diameter of 300 mm. Further, the effect of non-uniform tip clearance on the turbine performance was tested and the result was compared with that of the case of Wells turbine with uniform tip clearance. As an additional experiment, the effects of blade profile and non-uniform tip clearance on the performance under unsteady flow condition have been investigated numerically by using a quasi-steady analysis.

scholarly journals TURBINE−CHAMBER COUPLING IN AN OWC WAVE ENERGY CONVERTER

2012 ◽  
Vol 1 (33) ◽  
pp. 2 ◽  
Author(s):  
Ivan Lopez ◽  
Gregorio Iglesias ◽  
Mario Lopez ◽  
Francisco Castro ◽  
Miguel Ángel Rodríguez
Keyword(s):  
Numerical Modeling ◽  
Water Column ◽  
Wave Energy ◽  
Wave Power ◽  
Optimum Level ◽  
Oscillating Water Column ◽  
Wave Energy Conversion ◽  
Energy Converter ◽  
Air Turbine ◽  
Pneumatic Power

Oscillating Water Column (OWC) systems are one of the most popular technologies for wave energy conversion. Their main elements are the chamber with the water column and the air turbine. When studying the performance of an OWC system both elements should be considered together, for they are effectively coupled: the damping exerted by the air turbine affects the efficiency of the conversion from wave power to pneumatic power in the OWC chamber, which in turn affects the air flow driving the turbine. The optimum level of damping is that which maximizes the efficiency of the conversion from wave to pneumatic power. In this work the turbine-chamber coupling is studied through a combination of physical and numerical modeling.

scholarly journals Computational Fluid Dynamics Model of Wells Turbine for Oscillating Water Column System: A Review

2021 ◽  
Vol 2053 (1) ◽  
pp. 012013
Author(s):  
N. Abdul Settar ◽  
S. Sarip ◽  
H.M. Kaidi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Water Column ◽  
Cfd Simulation ◽  
Oscillating Water Column ◽  
Wells Turbine ◽  
Flow Problems ◽  
Cfd Models ◽  
Column System ◽  
Cfd Method

Abstract Wells turbine is an important component in the oscillating water column (OWC) system. Thus, many researchers tend to improve the performance via experiment or computational fluid dynamics (CFD) simulation, which is cheaper. As the CFD method becomes more popular, the lack of evidence to support the parameters used during the CFD simulation becomes a big issue. This paper aims to review the CFD models applied to the Wells turbine for the OWC system. Journal papers from the past ten years were summarized in brief critique. As a summary, the FLUENT and CFX software are mostly used to simulate the Wells turbine flow problems while SST k-ω turbulence model is the widely used model. A grid independence test is essential when doing CFD simulation. In conclusion, this review paper can show the research gap for CFD simulation and can reduce the time in selecting suitable parameters when involving simulation in the Wells turbine.

scholarly journals Millimeter Scale MEMS Air Turbine Generator by Winding Wire and Multilayer Magnetic Ceramic Circuit

2012 ◽  
Vol 02 (02) ◽  
pp. 41-46 ◽  
Author(s):  
Akane Iizuka ◽  
Minami Takato ◽  
Masato Kaneko ◽  
Tatsuya Nishi ◽  
Ken Saito ◽  
...  
Keyword(s):  
Turbine Generator ◽  
Air Turbine ◽  
Winding Wire

Analysis of the Wells Turbine Structure of an Oscillating Water Column Wave Energy System

2021 ◽  
pp. 53-62
Author(s):  
Mohamed Ali Jemni ◽  
Hamdi Hentati ◽  
Sawsan Elmbarki ◽  
Mohamed Salah Abid
Keyword(s):  
Water Column ◽  
Wave Energy ◽  
Energy System ◽  
Oscillating Water Column ◽  
Wells Turbine

scholarly journals Multilayer magnetic circuit for millimeter scale MEMS air turbine generator

2013 ◽  
Vol 47 ◽  
pp. 012015 ◽  
Author(s):  
M Takato ◽  
M Kaneko ◽  
T Nishi ◽  
K Saito ◽  
F Uchikoba
Keyword(s):  
Magnetic Circuit ◽  
Turbine Generator ◽  
Air Turbine

Efficiency Optimization in Low Inertia Wells Turbine-Oscillating Water Column Devices

2013 ◽  
Vol 28 (3) ◽  
pp. 553-564 ◽  
Author(s):  
Salvador Ceballos ◽  
Judy Rea ◽  
Iraide Lopez ◽  
Josep Pou ◽  
Eider Robles ◽  
...  
Keyword(s):  
Water Column ◽  
Oscillating Water Column ◽  
Wells Turbine ◽  
Efficiency Optimization

Hydrodynamic Analysis of a Vertical Axisymmetric Oscillating Water Column Device Floating in Finite Depth Waters

2012 ◽  
Author(s):  
Spyros A. Mavrakos ◽  
Dimitrios N. Konispoliatis
Keyword(s):  
Water Column ◽  
Wall Thickness ◽  
Vertical Cylinder ◽  
Finite Depth ◽  
Wave Forces ◽  
Oscillating Water Column ◽  
Wells Turbine ◽  
Present Contribution ◽  
Outer Atmosphere ◽  
Incident Waves

A floating oscillating water column device (OWC) consists of a vertical cylinder, with a finite wall thickness, partly submerged as an open-bottom chamber in which air is trapped above the inner water free surface. The chamber is connected with the outer atmosphere by a duct housing an air turbine. Forced by incident waves from any direction, the water surface inside pushes the dry air above through a Wells turbine system to generate power. In the present contribution the volume flows, the wave forces, the added mass and damping coefficients and the mean second-order loads for various configurations of OWC devices are being presented. Finally, it is tested how differentiations in the device’s geometry (wall thickness, draught, shape of the chamber, turbine characterises) affect the inner pressure and as a result the absorbed power by the device.

scholarly journals Self-Adaptive Global-Best Harmony Search Algorithm-Based Airflow Control of a Wells-Turbine-Based Oscillating-Water Column

2020 ◽  
Vol 10 (13) ◽  
pp. 4628 ◽  
Author(s):  
Fares M’zoughi ◽  
Izaskun Garrido ◽  
Aitor J. Garrido ◽  
Manuel De La Sen
Keyword(s):  
Water Column ◽  
Search Algorithm ◽  
Harmony Search ◽  
Harmony Search Algorithm ◽  
The Self ◽  
Oscillating Water Column ◽  
Wells Turbine ◽  
Control Scheme ◽  
Tuning Methods ◽  
Self Adaptive

The Harmony Search algorithm has attracted a lot of interest in the past years because of its simplicity and efficiency. This led many scientists to develop various variants for many applications. In this paper, four variants of the Harmony search algorithm were implemented and tested to optimize the control design of the Proportional-Integral-derivative (PID) controller in a proposed airflow control scheme. The airflow control strategy has been proposed to deal with the undesired stalling phenomenon of the Wells turbine in an Oscillating Water Column (OWC). To showcase the effectiveness of the Self-Adaptive Global Harmony Search (SGHS) algorithm over traditional tuning methods, a comparative study has been carried out between the optimized PID, the traditionally tuned PID and the uncontrolled OWC system. The results of optimization showed that the Self-Adaptive Global Harmony Search (SGHS) algorithm adapted the best to the problem of the airflow control within the wave energy converter. Moreover, the OWC performance is superior when using the SGHS-tuned PID.

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