Tesis sobre el tema "Oscillating water column (OWC)"
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Horko, Michael. "CFD optimisation of an oscillating water column wave energy converter". University of Western Australia. School of Mechanical Engineering, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0089.
Texto completoMedina-López, Encarnación. "Thermodynamic processes involved in wave energy extraction". Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31422.
Texto completoMoisel, Christoph y Thomas Carolus. "A facility for testing the aerodynamic and acoustic performance of bidirectional air turbines for ocean wave energy conversion". Elsevier, 2016. https://publish.fid-move.qucosa.de/id/qucosa%3A36338.
Texto completoLima, Yuri Theodoro Barbosa de. "Aplicação do método Design Construtal na avaliação numérica da potência hidropneumática de um dispositivo coluna de água oscilante com região de transição trapezoidal ou semicircular e estudo da influência da turbina no formato elíptico". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/153297.
Texto completoThe conversion of ocean’s wave energy into electrical energy is an alternative for the scarcity of fossil fuels. One of the possibilities of energy use is through devices, whose operating principle is the Oscillating Water Column (OWC). In this work the aim is, through computer modeling and the Constructal Design, to maximize hydropneumatic power of a power converter device type OWC. Different axes of physical constraint with elliptical shape, representing the effect of the turbine , are analyzed. Two geometric shapes in the transition region between the hydropneumatic chamber and the chimney OWC device, trapezoidal and semicircular, are also analyzed. Considering a two-dimensional domain the restrictions for this problem are: Elliptical restriction area (AR), Total area device (AT) and the ratio between the area of the elliptical restraint and the total area (ϕn). The considered degrees of freedom are: the ratio between the lengths of the axes (d1/d2) of the elliptical restraint, for the turbine’s physical constraint case, the inclination angle (α) of the wall for the trapezoidal transition case, and the radius (r) and H2/l (ratio between height and length of output chimney CAO) for the semicircular transition region case. For the numerical solution, a commercial code of computational fluid dynamics, FLUENT®, which is based on the Finite Volume Method (FVM), is employed. The multiphase model Volume of Fluid (VOF) is applied in the treatment of water-air interaction. The computational domain is represented by a wave tank with a fixed OWC device. The obtained results indicate that, for the study of the trapezoidal transition region, the performance of converter don’t seems to be compensatory only by changing the geometry of the trapezoidal area. However, for the semicircular transition region, it was possible to optimize a hydropneumatic power. The study of turbine effect indicates a geometry capable of converting the energy of the incident wave to the device, without obstructing the air flow in the chimney of de OWC, showing the relationship between the Constructal Design method and the wave climate in the definition of the dimensions that maximize the hydropneumatic power.
Kooverji, Bavesh. "Pneumatic power measurement of an oscillating water column converter". Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86662.
Texto completoENGLISH ABSTRACT: A measurement device was developed to accurately determine the pneumatic power performance of an Oscillating Water Column (OWC) model in a wave flume. The analysis of the pneumatic power is significant due to the wave-topneumatic energy being the primary energy conversion process and where the most energy losses can be expected. The aim of the research study is to address the accurate pneumatic power measurement of unsteady and bidirectional airflow in OWC model experiments. The two fundamental measurements required for the pneumatic power measurement are the pressure difference over an orifice on the OWC model and the volumetric flow rate of air through the outlet. The designed, constructed and assembled measurement device comprised of a venturi flow meter, containing a hot-film anemometer, which could measure the pressure drop and the volumetric flow rate in one device. The assembled pneumatic power measurement device was calibrated in a vertical wind tunnel at steady state. The results from the calibration tests showed that the volumetric flow rate measurements from the pneumatic power measurement device was accurate to within 3 % of the wind tunnel’s readings. The pneumatic power measurement device was incorporated onto a constructed Perspex physical model of a simple OWC device. This assembled system was used as the test unit in the wave flume at Stellenbosch University (SUN). The results from the experimental tests underwent comparative analysis with three analytical OWC air-flow models which were simulated as three scenarios using Matlab Simulink. These results showed that the measurement device has the ability to measure the pneumatic power but there is difficulty in modelling the complex air-flow system of the OWC device. This results in varying levels of agreement between the experimental and simulated pneumatic power results. The research study has revealed that there is difficulty in designing an accurate device for a wide range of test parameters due to the variance in output values. The unsteady and bidirectional nature of the air flow is also difficult to accurately simulate using a one-dimensional analytical model. Recommendations for further investigation are for CFD systems to be used for the analysis of the air-flow in an OWC system and to be used to validate future pneumatic power measurement devices.
AFRIKAANSE OPSOMMING: ‘n Meetinstrument was ontwikkel om die pneumatiese kraglewering van ‘n model van die Ossillerende Water Kolom (OWK) golfenergie omsetter in ‘n golf tenk akkuraat te meet. Dit is belangrik om die omskakeling van golf na pneumatiese energie te analiseer siende dat die grootste energieverlies in dié proses plaasvind. Die doel van hierdie navorsingsprojek was om die akkurate pneumatiese kragmeting van variërende en twee-rigting vloei van lug in ‘n OWK model na te vors. Die twee fundamentele metings wat benodig word vir die pneumatiese kragbepaling is die drukverskil oor die vloei vernouing en die volumetriese vloeitempo van lug deur die uitlaat van die toetstoestel. Die spesiaal ontwerpte meettoestel wat gebruik is in die eksperiment het bestaan uit ‘n venturi vloeimeter wat ‘n verhitte-film anemometer bevat het wat die drukverandering en die volumetriese vloeitempo kan meet in ‘n enkele instrument. Die pneumatiese kragmeting was gekalibreer in ‘n vertikale windtonnel waarin ‘n konstante vloei tempo geïnduseer was. Die kalibrasieproses het bevestig dat die meettoestel metings lewer met ‘n fout van minder as 3 % wanneer dit vergelyk word met die bekende konstante vloei tempo soos bepaal in die windtonnel. ‘n Fisiese model van ‘n vereenvoudigde OWK golfenergie omsetter was ontwerp en gebou uit Perspex om as toetstoestel te gebruik vir die evaluering van die ontwerpte pneumatiese kraglewering meettoestel. Die toetse was uitgevoer in ‘n golftenk by die Universiteit Stellenbosch (SUN). The toetsresultate was vergelyk met drie ander OWK lugvloei modelle wat gesimuleer was deur om die analitiese modelle op te stel en te simuleer in Matlab Simulink. Die vergelyking van modellering resultate het gewys dat die meettoestel die vermoë het om pneumatiese krag te meet. Daar was wel komplikasies met die modellering van die komplekse lugvloei in die OWK toestel, die resultate het geen definitiewe ooreenstemming gewys tussen die eksperimentele en gesimuleerde pneumatiese krag resultate nie. Die navorsingsprojek het gewys dat daar komplikasies is om ‘n enkel toestel te ontwerp wat oor ‘n wye bereik kan meet weens die variasie van die verskillende parameters. Die variërende en twee-rigting lugvloei is ook moeilik om akkuraat te simuleer met ‘n een-dimensionele analitiese simulasie model. Aanbevelings vir verdere navorsing sluit in om die lugvloei in die OWK stelsel te modelleer en te analiseer in ‘n drie-dimensionele model om die lesings van ‘n pneumatiese krag meettoestel te bevestig.
Perdigão, José Nuno Bebiano Mesquita de Azeredo. "Reactive-control strategies for an oscillating-water-column device". Phd thesis, Instituições portuguesas -- UTL-Universidade Técnica de Lisboa -- IST-Instituto Superior Técnico -- -Departamento de Engenharia Mecânica, 1998. http://dited.bn.pt:80/29667.
Texto completoMagagna, Davide. "Oscillating water column wave pump : a wave energy converter for water delivery". Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/349009/.
Texto completoMartins-rivas, Hervé. "Power extraction from an oscillating water column along a coast". Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45257.
Texto completoIncludes bibliographical references (p. 121-123).
For reasons of wave climate, geography, construction, maintenance, energy storage and transmission, some devices for extracting energy from sea waves will likely be installed on the coast. We study here the specific case where an Oscillating Water Column (OWC) is attached to the tip of a long breakwater. A three-dimensional numerical model of a skeletal geometry of the the Foz do Douro breakwater is developed in order to determine the response inside the OWC pneumatic chamber to incident waves and assess the possible effects of the breakwater geometry. The model uses the hybrid element method and linear water wave theory. Then, a more analytical approach for a simplified geometry is presented. Making use of an exact solution for the scattering by a solid cylinder connected to a wedge, we solve for the linearized problems of radiation and scattering for a hollow cylinder with an open bottom. Power-takeoff by Wells turbines above an air chamber is modeled by including the compressibility of air. It is shown for the case of a circular OWC attached to a thin breakwater, that the incidence angle affects only the waves in and outside the column but not the power extraction which depends only on the averaged water-surface displacement inside. Optimization by controlling the turbine characteristics is examined for a wide range of wavelengths. Finally, the same approach is used to solve the case of an OWC positioned along a straight coast line. It is found that in this configuration, the extracted power does depend on the incidence angle. It is also shown that the average efficiency is doubled compared to the thin breakwater geometry.
by Hervé Martins-rivas.
S.M.
Morrison, Iain George. "The hydrodynamic performance of an oscillating water column wave energy converter". Thesis, University of Edinburgh, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493723.
Texto completoLeitch, John Gaston. "Productivity analysis and optimization of oscillating water column wave power devices". Thesis, Queen's University Belfast, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329360.
Texto completoMinns, Julian. "Comparative performance of a novel oscillating water column wave energy converter". Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/10042.
Texto completoMackinnon, Pauline Anna. "The influence of geometry on turbulent losses in an oscillating water column". Thesis, Queen's University Belfast, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357453.
Texto completoFreeman, Kate. "Numerical modelling and control of an oscillating water column wave energy converter". Thesis, University of Plymouth, 2015. http://hdl.handle.net/10026.1/3290.
Texto completoDai, Saishuai. "Assessing the performance of an oscillating water column type wave energy device". Thesis, University of Strathclyde, 2016. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=27860.
Texto completoHolzhauer, Eva. "Assessment of the power available in a fixed offshore oscillating water column plant". Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/8053.
Texto completoBrendmo, Arne. "An investigation of wave-energy absorption by single and double oscillating water-column converters". Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 1995. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-14721.
Texto completoBayoumi, Ahmed Seif-Eldine Mohamed. "Development of numerical wave power prediction tool offshore oscillating water column wave energy converter". Thesis, University of Strathclyde, 2013. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=18992.
Texto completoCarolus, Thomas y Christoph Moisel. "Bidirectional air turbines for oscillating water column systems: Fast selection applying turbomachinery scaling laws". Elsevier, 2017. https://publish.fid-move.qucosa.de/id/qucosa%3A36340.
Texto completoStewart, Terence Patrick. "The influence of harbour geometry on the performance of oscillating water column wave power converters". Thesis, Queen's University Belfast, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359126.
Texto completoSparrer, Wendelle Faith. "Implementation and Demonstration of a Time Domain Modeling Tool for Floating Oscillating Water Columns". Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/101889.
Texto completoMaster of Science
Renewable energy is a critical component in combating climate change. Ocean wave energy is a source of renewable energy that can be converted into electricity using Wave Energy Converters (WECs). One such WEC is the floating Oscillating Water Column (OWC), which has been successfully field tested and warrants further exploration. Floating OWCs are partially submerged floating structures that have an internal chamber which water oscillates in. The motions of the water displace air inside this chamber, causing the air to be forced through a high speed turbine, which generates electricity. This research develops a publicly accessible code using MatLab and SimuLink to evaluate the motions and power generation capabilities of floating OWCs. This code is then validated against physical experiments to verify its effectiveness in predicting the device's motions. This publicly accessible code, known as the Floating OWC Iterative Time Series Solver (FlOWCITSS), showed error ranging from 1.5 % - 37% for the most important motions that are relevant to energy harvesting and power generation. These errors could be caused by the numerical models used, or uncertainties in experimental data. The presence of smaller error values shows potential for FlOWCITSS to achieve consistently higher fidelity results as the code undergoes further developments. To demonstrate the use of FlOWCITSS, geometry variations of floating OWCs are explored.
Simonetti, Irene [Verfasser] y Hocine [Akademischer Betreuer] Oumeraci. "Optimization of oscillating water column wave energy converters - a numerical study / Irene Simonetti ; Betreuer: Hocine Oumeraci". Braunschweig : Technische Universität Braunschweig, 2017. http://d-nb.info/1175816590/34.
Texto completoAhmed, Nisaar. "Thermo-fluid modelling of electrical generator frames under forced convection in an oscillating water column environment". Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31363.
Texto completoCrema, Ilaria [Verfasser] y Hocine [Akademischer Betreuer] Oumeraci. "Oscillating water column wave energy converters integrated in very large floating structures / Ilaria Crema ; Betreuer: Hocine Oumeraci". Braunschweig : Technische Universität Braunschweig, 2018. http://d-nb.info/1175815357/34.
Texto completoGuo, Lihui. "Applicability and potential of wave power in China". Thesis, University of Gävle, Department of Building, Energy and Environmental Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-7151.
Texto completoWave power is renewable energy which is environmentally friendly. Unlike most of renewable energy resources, wave energy can produce power all the year. The wave energy is stored in the ocean worldwide and highly concentrated near the ocean surface. It can be captured by wave power devices. Wave power is considered as a competitive energy resource in future.
Waves are generated by wind blows across the surface of sea. Wave energy is one kind of mechanical energy which will be used for electricity generation. Wave power can’t be used directly to generate electricity; at first the wave energy is converted into the other form of useful mechanical energy and then converted into electricity. Wave power has a high potential to be captured and used for generating electricity in future as the technology develops further.
Wave energy has been used since 1890s. There is a lot of energy stored in waves. 94% energy of the ocean stored in the wave, and the other 6% is tidal energy. Only small a part of the wave power is used for commercial electricity generation today.
The China is a developing country with a very large population which annually consume about 3073TWh electricity of which 496TWh is from renewable energy. The wave power was less than 1GWh in 2007 (reference from International Energy Agency). The World Energy Council has measured the total useful power of the ocean wave energy to be more than 2TW in the world and corresponding to 6000TWh per year. There is about 70GW useful wave power resources in China, equivalent to an annual useful wave power resource of 200TWh.
The lowest capital cost for the wave power system is today around 0.1Euro/kWh. China will in the future focus on the development electricity generation by wave power. There will be hundreds of new wave power plant built in China during the next twenty years, and the total installed capacity will be larger than 1GW at 2030, which delivers 3TWh annually. This corresponds to less than 1 percent of the total use of electricity in China.
This thesis focuses on the functionality, efficiency and economic pay-off of existing ocean wave power systems, as well as how easy the ocean wave power can produce electricity. Firstly it discusses the physical concepts of wave power, and then focus on the existing wave power systems around the world. It is concluded from the Chinese sea characteristics and the designed conditions of different wave power systems, that the Pelamis and Oyster wave power converters are the best suitable systems for China.
Larsson, Petter y Gustaf Rudbeck. "Wave Energy Concept Benchmarking". Thesis, KTH, Maskinkonstruktion (Inst.), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298841.
Texto completoThis report intends to examine the most common types of wave energy converter technologies to compare the different concepts' ability to absorb wave energy. Concepts being investigated are point absorbers and oscillating water columns (OWC). Calculations are made for the different concepts in the same wave conditions to be able to compare the energy that can be extracted. In the report, calculations are made under optimal wave conditions. The waves are assumed to be linear and the wave energy converter is assumed to be in phase with the oscillating motion of the wave. The wave data used is measured outside Belmullet in Ireland. Calculations are made on waves with a significant wave height of 1.25 m and a period time of 7.5 s. Calculations are also made on the largest measured wave present. In essence, power calculations are used according to a model developed by Kjell Budal and with the help of this be able to graphically and numerically compare the theoretical and actual maximum power that can be extracted from each scale. The results from the survey show that the largest contributing factor to high energy recovery is due to the volume of the buoy. The volume must be adapted to the wave conditions that exist where the buoy is to be placed.When calculating an OWC with a cross sectional area of 19 m2, it turns out that the power that can be extracted from an air chamber with an associated turbine is approximately 10 kW, 1/30 of the 300 kW that can be extracted by one point absorber. However, an OWC rarely consists of a single air chamber but often in a construction with several air chambers with separate turbines to increase the power.
Lara, Maria Fernanda Espinel. "Estudo numérico bidimensional com aplicação de constructal design para otimização da geometria e da profundidade de submersão de um dispositivo conversor de ondas do mar tipo coluna d'água oscilante". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/117786.
Texto completoThe present work aims to maximize the hydropneumatic power converted in an Oscillating Water Column (OWC) device. To do this, Constructal Design is applied to optimize its geometry and submergence. For the development of Constructal method, it has been proposed and analyzed three degrees of freedom: H1/ L (ratio between the height and length of OWC chamber), H2/l (ratio between height and length of chimney), and H3 (submergence). The problem constraints (fixed parameters) are total area of the OWC chamber A1 and total area of OWC device A2. The computational domain consists of an OWC inserted in a tank where waves in a real scale are generated. The mesh is developed in ANSYS ICEM®. The Computational Fluid Dynamics code FLUENT® is used to find the numerical solution which is based on Finite Volume Method (FVM). The multiphasic Volume of Fluid (VOF) model is applied to tackle with the water-air interaction. The results show that the maximum hydropneumatic power obtained was 190 W for H1/L, H2/l e H3 ratios equal to 0.135, 6.0 and 9.5 m respectively. In contrast, the smaller value obtained for the hydropneumatic power is almost 11 W. So, it shows the utility of Constructal Method which provides a relationship between the wave climate of a particular place and the optimal dimensions for the OWC device.
Gomes, Mateus das Neves. "Constructal design de dispositivos conversores de energia das ondas do mar em energia elétrica do tipo coluna de água oscilante". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/109161.
Texto completoThe present work presents a two-dimensional numerical study about the geometric optimization of an ocean Wave Energy Converter (WEC) into electrical energy. The main goal is, through computational modeling of a device whose operating principle is the Oscillating Water Column (OWC) and from employment Constructal Design, to maximize the conversion of energy of ocean waves into electricity. This technique is based on Constructal Theory. The inedited aspect of this work comparing to the available studies is that it takes into account the wave climate of a given region to design the device so that it achieves optimum performance. Constructal Design is employed varying the degrees of freedom H1/L (ratio between the height and length of OWC chamber) and H3 (lip submergence). While the relation H2/l (ratio between height and length of chimney) is kept fixed. Studies were performed considering a wave on a laboratory scale and a spectrum of real waves. Yet a study of the influence of the turbine pressure losses was performed using a physical constraint. For the numerical solution it is used the Computational Fluid Dynamic (CFD) commercial code FLUENT®, based on the Finite Volume Method (FVM). The geometry and mesh generation was performed in GAMBIT ® software. The multiphasic Volume of Fluid (VOF) model is applied to tackle with the water-air interaction. The computational domain is represented by an OWC device coupled with the wave tank. The results show that it is possible to establish a relationship of H1 / L optimum, if the wave climate is know. It is recommended that this ratio be equal to four times the height of the wave divided by the length of the incident wave.
Elhanafi, ASSM. "Performance and survivability of offshore oscillating water column wave energy converters". Thesis, 2017. https://eprints.utas.edu.au/23971/2/Elhanafi_whole_thesis_ex_pub_mat.pdf.
Texto completoMitchell, Ferguson TG. "An experimental investigation into WEC operation in realistic sea states using PIV". Thesis, 2016. https://eprints.utas.edu.au/23470/7/Mitchell_Ferguson_whole_thesis_ex_pub_mat.pdf.
Texto completoChi-ShengLin y 林啟聖. "Wave Loadings Distribution of Oscillating Water Column Caisson Breakwaters". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/36727018989237630297.
Texto completo國立成功大學
水利及海洋工程學系碩博士班
101
Renewable energy generation is currently under active development. Wave power is an example of such energy and could be one of the primarily developed source of energy for our country in the future. Within all the wave energy converter types, the oscillating water column system could be combined with caisson breakwater structures to provide both power supply generation and near shore protection. This study examines the stability and pneumatic reaction of the oscillating water column breakwater, using a Hualien test site. Spatial pressure measurements using surface water pressure on the caisson were used for stability analysis. The result shows that the gate of the oscillating water column breakwater may change the pressure distribution. For relative depths less than 0.2, the horizontal force of the oscillating water column breakwater can be approximated by the Goda formula, but rotating torque, however, is underestimated compared to the measurements. For the pneumatic reaction, the measurement result shows that, under the experimental constraints of this study, the wave conditions which create the best pneumatic reaction are coincident with the field wave conditions in Hualien. This study could be referenced for further development of wave energy in Taiwan.
Yang, Chung-Ying y 楊宗穎. "Numerical Simulation of Oscillating Water Column Wave Energy Converters". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/14747013454604375072.
Texto completo國立臺灣海洋大學
機械與機電工程學系
103
The thesis aims to study oscillating water column (OWC) wave energy converters (WEC) that are suitable for the northeast coast of Taiwan, and to simulate the OWC WEC model referring to the Limpet of Scotland by using computational fluid dynamics software ANSYS Fluent. There are three main topics to be studied: 1. to discuss the effect of chamber’s geometry to the conversion efficiency of the OWC WEC, specifically the inclined angle of the back wall; 2. to investigate the influence of the air duct size to the conversion efficiency without turbine installed; 3. to calculate the capture efficiencies of the Wells turbine by applying the preferred model size which is resulted from the above two investigations. From the previous literature, the relative geometric relation between chamber’s front and back walls has significant influence to the wave energy conversion efficiency. The simulation conditions are by fixing the air duct size and changing the inclined angles of the back wall, then to calculate the sum of kinetic energy, potential energy and pressure power, and used it as the criterion of the wave energy conversion efficiency. The air duct size is regarded closely related to Wells turbine’s capture efficiency. Hence, in order to compare the capture efficiency with different air duct sizes, the sum of kinetic energy and pressure power of different cases are calculated and compared as the criterion of capture efficiency. Finally, by using the preferred chamber geometry and the duct size combination based on the previous results, the overall power and capture efficiency are calculated with Wells turbine added. According to the simulation results, the chamber with 90-degree inclined angle of the back wall has the largest wave energy conversion efficiency, but it also has the largest energy loss. A comprehensive study shows that, the size of OWC has the preferred wave energy conversion efficiency with 60-degree back wall inclined angle and 65(mm) of the air duct radius. A simulation is performed to the above preferred geometry with Wells turbine installed. Under the wave conditions of wave height H= 0.07 (m), wave period T= 1.56 seconds, the result shows that the overall power of the OWC WEC is 0.1566 (W), the wave energy conversion efficiency 13.9%, and the Wells turbine’s capture efficiency 55.37%.
WeiChen y 陳葳. "Simulation of An Oscillating Water Column Type Wave Energy Conversion Device". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/30399424114803601471.
Texto completo國立成功大學
航空太空工程學系
102
SUMMARY The purpose of this study is to continue the research of Chun-Wei Mo (2013), “The Study of Converting Wave Energy by Using Air Pressure and Oscillating Water Column”, designing a 6 m-length, 2.3 m-width container with a Savonius vertical axial turbine wave energy device. From the previous study Chun-Wei Mo researched, water was filled in the generator sink. The wave motion will cause the liquid in the generator sink to reciprocate and motivate the turbine to generate. In order to obtain the performance of the blade from simulation, CFD method was employed. The software ANSYS CFX has been used in this study which is a numerical method used to solve 3-D Navier-Stokes equations with the finite volume method. The SST turbulence model was adopted to simulate the turbulent model. The self-adjusted tetrahedral non-structural grid was constructed based on the mesh generation software, ICEM. The major work in this study is to determine the operating condition for this design and discuss the power output in different wave type. Hence, the range of the volume flow from 1 m3/s to 12 m3/s has been simulated and each case is discussed, including the power output and efficiency. To determine the operating rotational speed, the method of predicting rotational speed is proposed in the simulation. Key words: wave energy, Savonius blade, CFD, OWC INTRODUCTION Due to the shortage of nonrenewable energy such as petroleum and coal, development of technology related to renewable energy has accelerated recent decades. A worldwide desire to limit our dependency on fossil fuels as a means to produce power has motivated research in solar, wind and wave energy as well. Wave energy is available in a variety of forms such as marine current, tidal current, geothermal vent and waves. The most commercially viable resources studied so far are ocean current and waves. In this study, a 6 m-length, 2.3 m-width container with a Savonius vertical axial turbine physical model filled with water was set up. This device was established to be an oscillating water column and it would generate power by waves. NUMERICAL METHOD Nowadays, CFD modeling provides a good description of flow field analysis with details usually available through physical modeling. In this study, numerical simulations have been performed. The software ANSYS CFX was used in this study which is a numerical method solved 3-D Navier-Stokes equations with the finite volume method. Grid generation uses ANSYS ICEM CFD to generate the unstructured tetrahedral mesh. Additionally, a few prismatic layers were established near the tip area to increase the precision of the simulation. In order to achieve the accurate result, k-ωSST turbulence model was adopted since k-ωSST turbulence model has been widely used to analyze Savonius type turbine in previous researches. RESULTS and DISCUSSION This study is mainly aimed to analyze the output characteristics of the entire system at different volume flow rates. After the selection of the Savonius type blade, a traditional combination of a semi-cylindrical five-leaf Savonius model, flow field at 1 ~ 4m3/ s has been simulated. Based on the output characteristics and flow channel, the shape of the original blades was modified, improving the performance of the blade. To understand the physical condition of such device, and properties of the output of the modified Savonius rotor, the flow through the inlet section of the housing 1 ~ 12 m3/ s has been simulated. The results of the simulation showed the performance of the modified type blade was higher than that of the original one. In addition, the results indicated the power output is less than 30 kW at 1 ~ 5m3/ s; 30~60 kW at 6 ~ 7m3 / s and 100 ~ 300 kW at 8 ~ 12m3/ s. The value of performance efficiency is located within 0.06 to 0.08. The flow field of the whole system shows that there is a huge low pressure region with some vortex. Furthermore, this research is used to estimate the actual output performance of the wave power device based on this hydraulic turbine. As different environments caused different wave motions, this study only considered the wave period at eight seconds, and the half cycle can lead to eight tons of water flowing through the blade as physical conditions. Based on the physical conditions, 3 different types of waves were plotted to estimate a possible value of power output. The maximum volume flow rate of three different waveforms 3m3/s, 6 m3/s and 12 m3/ s, totaled to a maximum output power of 5.94 kW, 39 kW, 294.45 kW respectively. The corresponding values of the average power output during a period are 0.75 kW, 5.75 kW, and 37 kW.
Lin, Chi-Chien y 林繼謙. "Design of a Wave Energy System Using Onshore Oscillating Water Column". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/20868481000012919856.
Texto completo國立成功大學
系統及船舶機電工程學系碩博士班
97
This thesis investigates the feasibility of applying oscillating water column (OWC) wave energy system to the onshore area in Taitung, Taiwan. A laboratory scale prototype of the OWC wave energy system is built based on the surveyed wave data at the target site. The prototype is scaled down using the Froude number theory for equivalence to the real site condition. The OWC is designed to have two chambers and two cascaded Savonius turbines, each of them being used for one chamber of the OWC. This configuration helps to stabilize the air flow passing the turbines so that the rotational speed the the turbines can be more steady than that with single chamber. Consequently, the cost on power electronics can be reduced and the quality of the power output can be maintained. The designed side-mounted OWC, differing from conventional systems, is structurally parallel to the propagation of the waves and allows the wave to penetrate the OWC. This will enhance the conversion rate for transferring wave energy to the chamber air, and thus the turbine. The OWC and the permanent-magnet generator are designed in a systematic manner for better system efficiency. The prototype is tested for performance validation.
Fleming, AN. "Phase-averaged analysis of an oscillating water column wave energy converter". Thesis, 2012. https://eprints.utas.edu.au/15913/1/front-flemming-2012.pdf.
Texto completoChih-YinChung y 鍾智印. "Numerical study on air-water responses of oscillating water column wave energy caisson breakwater". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/g9uc49.
Texto completoChuang, Chia-Yu y 莊佳于. "Experiments on Hydrodynamic Characteristics of Wave Energy Absorber with Oscillating Water Column". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/39174478439422180628.
Texto completo國立中興大學
土木工程學系所
104
The study of the wave power capture system has been gone for years around the world. Among the variety types of ocean wave energy absorbed system, the Oscillating Water Column (OWC) system could be considered a major, it has been evaluated for decades with many investigations of. This paper presents a new type of wave energy absorber embodying OWC system from Tsai (2016), and discussing its hydrodynamic characteristics adopted different wave definitions by physical model tests in this study. The experimental tests measured the oscillation of water column and used the high speed camera with laser system to do flow visualization. The study also compare with the U-OWC from Boccotti (2007) and the conventional OWC. When the water column of the air chamber oscillating by the waves, it will compress the air and generate the wind speed at the device. When the water column rise up it will cause the air flow out from the device, and flow in when it comes down. From the stabilization of water column variation, the wind speed caused by the water column will also be stabilize. The study adopted different wave definitions to discuss the relation between the wind speed and the wind power and the relation between the relative width and the wave reflection from OWC, the wave pressure on the OWC. The result shows the smaller of the relative width B/L(B : the width of OWC, L : the wavelength) of OWC and the larger of the Ursell parameter of incident wave induce the larger of the wind speed which it was generated and produced much more wind power in the different incident wave height conditions. On the other hand the result indicates that the wave reflection from OWC and the wave pressure on the OWC is minimal when B/L is about 0.16.The study also compare with the U-OWC and the conventional OWC, the result shows that the present absorber not only capture more wind power than the U-OWC and the conventional OWC but also the wave reflection from OWC and the wave pressure on the OWC is less than the other two.
Wang, Hao. "Wave Energy Extraction from an Oscillating Water Column in a Truncated Circular Cylinder". Thesis, 2013. http://hdl.handle.net/1969.1/151188.
Texto completoChia-YingChang y 張家穎. "Analytical and Experimental Investigation of Chamber Hydrodynamic Performance of Oscillating Water Column System". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/jkdswa.
Texto completo國立成功大學
水利及海洋工程學系
105
Renewable green energy is becoming increasingly important due to the expected limit of fossil energy resources and to reduce pollution. Wave energy generation technology has been significantly developed in recent years among numerous types of renewable energy. Fixed breakwater, used to protect shorelines, marine structures, moored vessels, marinas and harbors from wave attacks, may be considered as a common site for installing oscillating water column (OWC) for exploited wave energy. Wave energy have been considered by many experts as one of the most promising green energy for Taiwan. However, the amount of wave energy presently generated constitutes a minor percentage of Taiwan’s total energy production. This paper presents experimental results of a laboratory water chamber of OWC, wherein the fundamental parameters of geometrical design are individually investigated and optimized, for maximum wave energy. The effects of a variety of back plates angle, fence plates and open wide inlets of OWC chamber are analyzed and tested for catching capability of wave energy. Three experimental models are tested to include an evaluation of the effectiveness of back plate, fence plate and open wide inlet. The operation of OWC qualitatively differs from that predicted by linear theory, identify to critical flow characteristic; front wall down-wash in the water column. The surveys were then expanded to offer general arrangement or a planning material for the geometry optimization of the chamber that could potentially achieve the largest average amplification factor of an OWC system. The wave energy in the OWC significantly varies with different back angles. The results demonstrate that this new OWC could provide more efficient wave energies.
Howe, DP. "Integration of oscillating water column wave energy converters within multi-use maritime structures". Thesis, 2020. https://eprints.utas.edu.au/35841/1/Howe_whole_thesis_ex_pub_mat.pdf.
Texto completoChun-WeiMo y 莫鈞維. "The Study of Converted Wave Energy by Using Air Pressure and Oscillating Water Column". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/83796694558994875864.
Texto completo國立成功大學
航空太空工程學系碩博士班
101
The purpose of this study is to design a wave-energy device to convert wave energy. Oscillating water column type of wave-energy device has a good adaptation for different topographies, and it is easy to design. Due to the loss of energy density, the method of generating power by using oscillating water column to push air would lower the output. In this experiment, a wave nergy device is designed to improve the power generating system. Also, it verifies the feasibility of using air pressure to generate oscillating water column in order to create the difference in the water level that can produce energy to push the water turbine. The device of the experiment is an oscillating water column type of energy device that its air chamber part is connected to a generator-sink. Therefore, the generator-sink and air chamber become an enclosed space. In this way, the oscillating water column changes the air pressure in the air chamber, and the inside air pressure changes the water level in the generator sink. To simplify the mechanism of this experiment, no turbine is installed on the wave-energy device. We can get the maximum potential energy by measuring the wave height on the air chamber wall, the air pressure between the air chamber and the generator sink, and the change of water level in the generator sink. The parameters of the wavemaker in this experiment are the local water depth, the stroke , and the frequency of paddle. The stroke of paddle is 0.2m, 0.3m, and 0.4m. The wave period is in the range of 1.5s to 3.4s. The ratio of the wave height in the generator sink to the wave height on the air chamber wall are 19% to 68%(when the stroke is 0.2m), 30% to 61%( when the stroke is 0.3m) , and 19% to 68%(when the stroke is 0.4m). Obviously, the maximum potential energy of the generator sink is larger than the potential energy when a wind turbine is equipped at the end of the air chamber.
Luo, Yuan-Ting y 羅元廷. "Hydrodynamic Characteristics of a New Type of Wave Energy Absorber with Oscillating Water Column". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/99267938082982984562.
Texto completoKo, Chun-Han y 柯鈞瀚. "Study on Hydrodynamic Performance of a Breakwater-Integrated Oscillating Water Column Wave Energy Converter". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/d4kzs4.
Texto completo國立中興大學
土木工程學系所
107
This study is aimed to investigate the hydrodynamic and aerodynamic performances of an innovative breakwater-integrated oscillating water column (OWC) wave energy converter. This innovative OWC device consists of an extra perforated wall in front of the typical OWC chamber, which can be integrated with a caisson breakwater for capturing efficiently the wave power. The characteristics of the flow behavior in the OWC chamber and the effect of structural geometry on the hydrodynamic efficiency of the device are investigated by adopting both numerical simulations and laboratory experiments. The CFD numerical model for solving this air-water and wave-structure interaction problems is based on the three-dimensional RANS equations and the RNG -ε turbulent closure model, from which the numerical simulations is implemented by the Flow-3D software. The numerical model is first validated by using previous PIV experimental results for a typical OWC chamber and the present experiments for the innovative OWC device. Then the numerical simulations considering full scale OWC model are implemented for exploring the water and air flow characteristics and the geometric effect on the hydrodynamic performance parameters, including the water column surface elevation, the differential air pressure in the chamber, the airflow rate through the orifice and the pneumatic power. Based on the numerical simulations and experimental investigation, it is found that the larger velocity of water flow and the corresponding vortices always occur near the lip of the front submerged wall, and the airflow forms a conical shape due to the circular orifice on the roof centre of chamber. The maximum positive and negative differential air pressures in the chamber occur at the instant as the mean water level of the oscillating water column commences upward and downward, respectively. The positive and negative differential air pressure inside the chamber induce the air to extrude and suck through the orifice. The effects of the chamber geometry including the chamber breadth, the open height of front submerged wall, the orifice size and porosity of the front perforated wall are discussed by simulations considering full scale model of the present OWC device. It is found that the following remarkable effects. (i) The maximum pneumatic efficiency could reach to about 84% under the resonant frequency condition and the optimized geometry. (ii) The resonant frequency condition decreases with the increase of the breadth of the OWC chamber. (iii) The smaller and larger entrances of the open submerged wall could not produce higher pneumatic power, which the optimum value is found as 0.6 times of the water depth. (iv) The smaller orifice area might induce the larger the airflow velocity across the orifice and the larger differential air pressure in the chamber, however it does not produce the larger the pneumatic power due to the lower airflow rate. The max hydrodynamic efficiency happened as the orifice area ratio is 0.7%. (v) The front perforated wall could influents the wave reflection coefficient and the dissipation of turbulent kinetic energy, and reaches the max hydrodynamic efficiency when the porosity is 25%. Finally, by the comparisons the hydrodynamic performance between present and typical OWC, it shows that the present OWC device has better performance for pneumatic power extraction and less wave pressure on the front submerged wall.
LIU, YUNG-CHING y 劉永慶. "Experimental Study on the Optimization of an Oscillating Water Column System Considering Real Gas Compressibility". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/q77246.
Texto completo東南科技大學
營建科技與防災研究所在職專班
105
Renewable energy for the government is currently actively developing the energy, Taiwan surrounded by the sea, the winter has a strong northeast monsoon, so that the eastern and northeastern Taiwan have considerable potential for wave power generation, which oscillates the water column system may become the future wave development type one. In this study, the experiment shows the oscillating water column type power generation system (OWC)corresponding to the water depth ratio acrylic model to observe and record the wave height, pressure and outlet wind speed in the tank with different wave-making conditions. Considering the real gas compressibility and considering the different openings and gates The optimal rate of the average wind speed, the maximum average wind speed and the maximum wind speed is compared with the difference between the open rate and the maximum wind speed. Considering the real gas compressibility and gas tank respectively according to the different opening and the gate opening rate corresponding to different wave conditions the average wind speed, average wind speed and maximum wind speed to find the optimal alignment analysis of the test of the oscillating water column type power system design, according to the test results found that the average wind speed, in the condition of D=50mm the maximum average wind speed and maximum wind speed under the condition of opening height is not much difference in the G=175mm and G=200mm gate, but when G=200mm meets the low trough may have occurred to the cabin air lead to instability, and considering the need to consider the shore type marine high and low tide difference factors, according to the experimental results evaluation of gate opening height of G=175mm (opening rate 175mm/250mm=70%) and the gas tank outlet aperture D=50mm for optimal OWC design.
Chiu, Chao-Chin y 丘兆欽. "Development of Flexible PZT Composite Film for Oscillating Water Column Type Wave Energy Converter Application". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/63694348907688346152.
Texto completo國立中興大學
機械工程學系所
104
The dissertation proposes to develop an oscillating water column(OWC) type wave energy converter(WEC) using flexible lead zirconate titanate(PZT) composite films. An OWC type WEC uses the motion of ocean surface waves to create oscillating water column and generate electricity. The converter with an impacting plate moves by ocean wave energy and generate electric energy. The power generating elements of converter is made by PZT composite films of disk type. Flexible PZT composite films were fabricated by sol-gel pro- cess on the copper/nickel composite substrates.Its thickness is 13.65 μm, the impedance is 3.47 kΩ, the phase is -88.51°, the capacitance is 45.83 nF, the dielectric loss is 2.60% and the relative dielectric constant is 15.69 at the fre- quency of 1kHz. The analytic and finite element models of converters will be studied and analyzed. By the finite element analysis, the resonance fre- quency of first resonance mode is 103.3 Hz. By the measurement, the OWC type WEC generates a maximum voltage of 30.2 mV at the resonance fre- quency of 97.25 Hz.
Rajapakse, G. "Control and power management of grid connected vented oscillating water column wave energy converter arrays". Thesis, 2021. https://eprints.utas.edu.au/37931/1/Rajapakse_whole_thesis.pdf.
Texto completoPestana, Ronaldo Jorge. "The modelling of a squirrel-cage induction generator in an oscillating-water-column wave-energy converter". Thesis, 2015. http://hdl.handle.net/10539/17557.
Texto completoAnsarifard, N. "CFD analysis and optimisation of unidirectional radial turbine geometry for application with oscillating water column wave energy converters". Thesis, 2019. https://eprints.utas.edu.au/32532/1/Ansarifard_whole_thesis.pdf.
Texto completoHuang, Ching-En y 黃靖恩. "Studies on Hydrodynamic and Air-flow Characteristics of a New Type of Wave Energy Absorber with Oscillating Water Column". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/89881230929171578420.
Texto completo國立中興大學
土木工程學系所
103
This paper presents a new type of wave energy absorber embodying OWC system, and discussing its hydrodynamics and air-flow characteristics. Using both computational fluid dynamics (CFD) and physical model tests in this study. A CFD called Flow-3D was employed, which one-fluid model is used to simulate the flow field of the oscillation of water column, and two-fluid model is adopted to simulate the wind field. The experimental tests measured the oscillation of water column and used the high speed camera with laser system to do flow visualization. The results show that the simulations of the flow field, the wind field and the free surface variation of the water column are quite constant and the same with the experimental tests. According to the results, when the water column of the air chamber oscillating by the waves, it will compress the air and generate the wind speed at the device. When the water column rise up it will cause the air flow out from the device, and flow in when it comes down. From the stabilization of water column variation, the wind speed caused by the water column will also be stabilize. The study adopted different wave definitions to discuss the relation between the wind speed and the wind power. The result shows the larger of the wave height induce the larger of the wind speed which it was generated and produced much more wind power in the different incident wave height conditions. In the same wave height but different relative depth conditions,the OWC device will absorber more wind power when the relative depth is decreasing. When the width of the air chamber b over the structure width B from OWC device is increasing,the OWC device will absorber more wind power in the same wave height and relative depth conditions. The study also compare with the conventional OWC,and the result shows that the present one absorber more wind power than the conventional one.
Rodriguez-Macedo, Julio Cesar. "Design and experimental evaluation of a unidirectional flow collective air pumps wave energy converter". Thesis, 2017. https://dspace.library.uvic.ca//handle/1828/8957.
Texto completoGraduate