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A Twin Unidirectional impulse turbine for Wave Energy Conversion

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Journal of Thermal Science 2011年第5期20卷 394-397页

作者： Manabu Takao Akiyasu Takami Shinya Okuhara Toshiaki Setoguchi Matsue College of Technology 14-4 NishiikumaMatsueShimane 690-8518Japan Saga University 1 HonjoSagaSaga 840-8502Japan

A twin unidirectional impulse turbine has been proposed in order to enhance the performance of wave energy plant. This turbine system uses two unidirectional impulse turbines and their flow direction is different from each other. However, the turbine characteristics have not been clarified to date. The performances of a unidirectional impulse turbine under steady flow conditions were investigated experimentaUy by using a wind tunnel with large piston/cylinder in this study. Then, efficiency of the twin impulse turbine have been estimated by a quasi-steady analysis using experimental results.

关键词： Fluid machinery impulse turbine wave energy conversion ocean energy.

Experimental Investigation on a Fixed Oscillating Water Column with an impulse turbine for Wave Energy Conversion

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Journal of Energy and Power Engineering 2020年第1期14卷 16-25页

作者： Tengen Murakami Yasutaka Imai Shuichi Nagata Manabu Takao Institute of Ocean Energy Saga University1HonjoSaga 840-8502Japan Department of Mechanical Engineering National Institute of TechnologyMatsue College14-4NishiikumaMatsueShimane 690-8518Japan

A fixed oscillating water column(OWC)-type wave energy converter consists of an air chamber,an air turbine and a *** energy conversion processes are the primary conversion in an air chamber and the secondary conversion of the *** the practical use,it is necessary to develop a design method which can consider the incident wave motion,the motion of the internal free surface affected in the structure such as a partly submerged wall,the fluctuation of air pressure in an air chamber,and the rotation of the air *** here,the authors carried out the wave tank tests using the model OWC equipped with the impulse turbine and a generator to obtain the experimental data needed to make this design *** the result,the efficiencies of the three cases with different speed ratio between generator and turbine,and the effects of the curtain wall depth and the wave length on the energy conversion performance were clarified.

关键词： impulse turbine oscillating water column primary conversion secondary conversion wave energy

A RANS-VoF Numerical Model to Analyze the Output Power of An OWC-WEC Equipped with Wells and impulse turbines in A Hypothetical Sea-State

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China Ocean Engineering 2020年第6期34卷 760-771页

作者： Paulo R.F.Teixeira Rafael A.A.C.Gonçalves Eric Didier Engineering School Universidade Federal do Rio Grande-FURGRio GrandeRS 96203-900Brazil Harbours and Maritime Structures Division Hydraulics and Environment DepartmentLaboratório Nacional de Engenharia Civil-LNECLisbon 1700-066Portugal

Wave energy is a renewable source with significant amount in relation to the global demand. A good concept of a device applied to extract this type of energy is the onshore oscillating water column wave energy converter(OWC-WEC). This study shows a numerical analysis of the diameter determination of two types of turbines, Wells and impulse, installed in an onshore OWC device subjected to a hypothetical sea state. Commercial software FLUENT?,which is based on RANS-VoF(Reynolds-Averaged Navier-Stokes equations and Volume of Fluid technique), is employed. A methodology that imposes air pressure on the chamber, considering the air compressibility effect, is used. The mathematical domain consists of a 10 m deep flume with a 10 m long and 10 m wide OWC chamber at its end(geometry is similar to that of the Pico's plant installed in Azores islands, Portugal). On the top of the chamber, a turbine works with air exhalation and inhalation induced by the water free surface which oscillates due to the incident wave. The hypothetical sea state, represented by a group of regular waves with periods from 6 to 12 s and heights from 1.00 to 2.00 m(each wave with an occurrence frequency), is considered to show the potential of the presented methodology. Maximum efficiency(relation between the average output and incident wave powers) of46% was obtained by using a Wells turbine with the diameter of 2.25 m, whereas the efficiency was 44% by an impulse turbine with the diameter of 1.70 m.

关键词： wave energy oscillating water column Wells turbine impulse turbine RANS-VoF compressible air

Experimental and numerical investigation of design optimization of a partial admitted supersonic turbine

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Propulsion and Power Research 2013年第1期2卷 70-83页

作者： Reza Aghaei tog Abolghasem M.Tousin Amirkabir University of Technology TehranPO.BOX 15875-4413Iran

To obtain a high specific work output,the large pressure ratios across the turbine are *** can be achieved using a supersonic *** the fluid mass flow is low,the impulse kind of one or two stages supersonic turbine is *** prevent losses due to low blade aspect ratio and issues related to manufacturing and industrial problems,the turbine is used in partial admission *** show that the turbine efficiency is highly dependent on the amount of partial admission *** turbine efficiency in full admission is high,but the use of partial admission lowers the additional ***,there will be a degree of partial admission in which the turbine will have the highest *** aim of this work is to achieve the optimum partial admission for a special impulse turbine as a case ***,in the beginning,an appropriate model of losses is ***,using a nonlinear design optimization code,the partial admission of an impulse supersonic turbine is *** code is written using a genetic ***,using three-dimensional numerical analysis,the optimal model will be *** the optimization problem,the turbine efficiency is the objective *** amount of design parameters and constraints used in this process are ten and eight,*** the optimization process,prototypes of designed and modified turbines are made and *** results were compared and *** results showed that the turbine efficiency is improved between 2.5%and 3%depending on various operation conditions.

关键词： Partial admission Non-linear optimization Genetic algorithm Three-dimensional(3D)numerical analysis impulse turbine

Performance estimation of bi-directional turbines in wave energy plants

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Journal of Thermal Science 2007年第4期16卷 346-352页

作者： S.Anand V.Jayashankar S.Nagata K.Toyota M.Takao T.Setoguchi Department of Electrical Engineering IIT MadrasIndia IOES Saga UniversityJapan Department of Mechanical Engineering Matsue National College of TechnologyJapan Department of Mechanical Engineering Saga UniversityJapan

Oscillating water column （OWC） based wave energy plants have been designed with several types of bidirectional turbines for converting pneumatic power to shaft power. impulse turbines with linked guide vanes and fixed guide vanes have been tested at the Indian Wave Energy plant. This was after initial experimentation with Well＇s turbines. In contrast to the Well＇s turbine which has a linear damping characteristic, impulse turbines have non-linear damping. This has an important effect in the overall energy conversion from wave to wire. Optimizing the wave energy plant requires a turbine with linear damping and good efficiency over a broad range of flow coefficient. This work describes how such a design can be made using fixed guide vane impulse turbines. The Indian Wave Energy plant is used as a case study.

关键词： Bidirectional turbine differential pressure flow rate impulse turbine

Numerical Study on Air turbines with Enhanced Techniques for OWC Wave Energy Conversion

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China Ocean Engineering 2017年第5期31卷 517-527页

作者： CUI Ying HYUN Beom-Soo KIM Kilwon Department of Ocean Engineering College of EngineeringOcean University of China Division of Naval Architecture and Ocean Engineering Korea Maritime and Ocean University

In recent years,the oscillating water column(OWC) wave energy converter,which can capture wave energy from the ocean,has been widely applied all over the *** the essential part of the OWC system,the impulse and Wells turbines are capable of converting the low pressure pneumatic energy into the mechanical shaft *** an enhanced technique,the design of endplate or ring attached to the blade tip is investigated numerically in this paper.3 D numerical models based on a CFD-software FLUENT 12.0 are established and validated by the corresponding experimental results from the reports of Setoguchi et al.(2004) and Takao et al.(2001).Then the flow fields and non-dimensional evaluating coefficients are calculated and analyzed under steady *** show that the efficiency of impulse turbine with ring can reach up to 0.49 when Ф=1,which is 4% higher than that in the cases for the endplate-type and the original *** the ring-type Wells turbine with fixed guide vanes shows the best performance with the maximal efficiency of 0.55,which is 22% higher than that of the original *** addition,the quasi-steady analysis is used to calculate the mean efficiency and output-work of a wave cycle under sinusoidal flow *** all together,this study provides support for structural optimization of impulse turbine and Wells turbine in the future.

关键词： OWC impulse turbine Wells turbine CFD endplate ring quasi-steady analysis

Effect of partial blockage of air duct outlet on performance of OWC device

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Journal of Central South University 2012年第3期19卷 748-754页

作者： S.Patel K.Ram M.Rafiuddin Ahmed Renewable Energy Research Group University of the South Pacific

The use of a Savonius rotor as turbine for an oscillating water column(OWC) is *** effect of tuning the OWC using turbine duct blockage is also studied for different wave conditions.A horizontal turbine section OWC employing a Savonius rotor was tested by varying the opening of OWC exit(0%,25%,50%,75% and 100%) to study the behavior and performance of the *** OWC model was tested at water depth of 0.29 m at frequencies of 0.8,0.9 and 1.0 Hz while the exit openings are *** static pressure,dynamic pressure,rotational speed of the Savonius rotor and the coefficient of power are presented as *** OWC with exit opening of 25% showed greater performance in terms of rotational speed and CP compared to OWC with other exit opening *** proves the ability of the OWC to be tuned by regulating flow in the turbine duct.

关键词： oscillating water column wave energy converter wells turbine impulse turbine Savonius rotor

Comparative Study of turbines for Wave Energy Conversion

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Journal of Thermal Science 2001年第1期10卷 26-31页

作者： HideakiMaeda ToshiakiSetoguchi 等 TorishimaPumpMfg.Co.Ltd. 1－1－8Miyata－machiTakatsuki－shiOsaka569－8660Japan DepartmentofMechanical

The objective of this paper is to compare the performances of the themes, which could be used for wave energy conversion in the near future, under various irregular wave conditions. The turbines included in the paper are as follows: (a) Wells turbine with guide vanes; (b) impulse turbine with self-pitch-controlled guide vanes; (c) impulse turbine with fixed guide vanes. In this study, experimental investigations were carried out to clarify the performances of the turbines under steady flow conditions, and then a numerical simulation was used for predicting the performances under irregular wave conditions with various significant wave heights. As a result it was found that the running and starting characteristics of the impulse turbines could be superior to those of the Wells turbine.

关键词： fluid machinery Wells turbine impulse turbine wave power conversion ocean energy.