Download or read book Marine Hydrokinetic Turbine Power take off Design for Optimal Performance and Low Impact on Cost of energy written by M. Beam and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Marine Hydrokinetic Turbine Power take off Design for Optimal Performance and Low Impact on Cost of energy written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Marine Hydrokinetic Turbine Power take off Design for Optimal Performance and Low Impact on Cost of energy written by and published by . This book was released on 2012 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine hydrokinetic devices are becoming a popular method for generating marine renewable energy worldwide. These devices generate electricity by converting the kinetic energy of moving water, wave motion or currents, into electrical energy through the use of a Power-Take-Off (PTO) system. Most PTO systems incorporate a mechanical or hydraulic drive train, power generator and electric control/conditioning system to deliver the generated electric power to the grid at the required state. Like wind turbine applications, the PTO system must be designed for high reliability, good efficiency, and long service life with reasonable maintenance requirements, low cost and an appropriate mechanical design for anticipated applied steady and unsteady loads. The ultimate goal of a PTO design is high efficiency, low maintenance and cost with a low impact on the device Cost-of-Energy (CoE).

Download or read book Marine hydrokinetic turbine power take off design for optimal performance and low impact on cost of energy written by M. Beam and published by . This book was released on 2013 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Performance Evaluation Emulation and Control of Cross flow Hydrokinetic Turbines written by Robert J. Cavagnaro and published by . This book was released on 2016 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cross-flow hydrokinetic turbines are a promising option for effectively harvesting energy from fast-flowing streams or currents. This work describes the dynamics of such turbines, analyzes techniques used to scale turbine properties for prototyping, determines and demonstrates the limits of stability for cross-flow rotors, and discusses means and objectives of turbine control. This involves a progression from the analysis of a laboratory-scale prototype turbine to the emulation of a field-scale commercial turbine under realistic control. Understanding of turbine and system component dynamics and performance is leveraged at each phase, with the ultimate goal of enhancing the efficacy of prototype testing and enabling safer, more advanced control techniques. Novel control strategies are under development to utilize low-speed operation (slower than at maximum power point) as a means of shedding power under rated conditions. However, operation in this regime may be unstable. An experiment designed to characterize the stability of a laboratory-scale cross-flow turbine operating near a critically low speed yields evidence that system stall (complete loss of ability to rotate) occurs due, in part, to interactions with turbulent decreases in flow speed. The turbine is capable of maintaining 'stable' operation at critical speed for short duration (typically less than 10 s), as described by exponential decay. The presence of accelerated 'bypass' flow around the rotor and decelerated 'induction' region directly upstream of the rotor, both predicted by linear momentum theory, are observed and quantified with particle image velocimetry (PIV) measurements conducted upstream of the turbine. Additionally, general agreement is seen between PIV inflow measurements and those obtained by an advection-corrected acoustic Doppler velocimeter (ADV) further upstream. Definitive evidence linking observable flow events to the onset of system stall is not found. However, a link between turbulent kinetic energy of the flow, the system time constant, and the turbine's dynamic response to turbulence indicates changes in the flow occurring over a horizon of several seconds create the conditions under which system stall is likely. Performance of a turbine at small (prototype) geometric scale may be prone to undesirable effects due to operation at low Reynolds number and in the presence of high channel blockage. Therefore, testing at larger scale, in open water is desirable. A cross-flow hydrokinetic turbine with a projected area (product of blade span and rotor diameter) of 0.7 m^2 is evaluated in open-water tow trials at three inflow speeds ranging from 1.0 m/s to 2.1 m/s. Measurements of the inflow velocity, the rotor mechanical power, and electrical power output of a complete power take-off (PTO) system are utilized to determine the rotor hydrodynamic efficiency (maximum of 17%) and total system efficiency (maximum of 9%). A lab-based dynamometry method yields individual component and total PTO efficiencies, shown to have high variability and strong influence on total system efficiency. The method of tow-testing is found effective, and when combined with PTO characterization, steady-state performance can be inferred solely from inflow velocity and turbine rotation rate. Dynamic efficiencies of PTO components can effect the overall efficiency of a turbine system, a result from field characterization. Thus, the ability to evaluate such components and their potential effects on turbine performance prior to field deployment is desirable. Before attempting control experiments with actual turbines, hardware-in-the-loop testing on controllable motor-generator sets or electromechanical emulation machines (EEMs) are explored to better understand power take-off response. The emulator control dynamic equations are presented, methods for scaling turbine parameters are developed and evaluated, and experimental results are presented from three EEMs programmed to emulate the same cross-flow turbine. Although hardware platforms and control implementations varied, results show that each EEM is successful in emulating the turbine model at different power levels, thus demonstrating the general feasibility of the approach. However, performance of motor control under torque command, current command, or speed command differed; torque methods required accurate characterization of the motors while speed methods utilized encoder feedback and more accurately tracked turbine dynamics. In a demonstration of an EEM for evaluating a hydrokinetic turbine implementation, a controller is used to track the maximum power-point of the turbine in response to turbulence. Utilizing realistic inflow conditions and control laws, the emulator dynamic speed response is shown to agree well at low frequencies with simulation but to deviate at high frequencies. The efficacy of an electromechanical emulator as an accurate representation of a fielded turbine is evaluated. A commercial horizontally-oriented cross-flow turbine is dynamically emulated on hardware to investigate control strategies and grid integration. A representative inflow time-series with a mean of 2 m/s is generated from high-resolution flow measurements of a riverine site and is used to drive emulation. Power output during emulation under similar input and loading conditions yields agreement with field measurements to within 3% at high power, near-optimal levels. Constant tip-speed ratio and constant speed proportional plus integral control schemes are compared to optimal nonlinear control and constant resistance regulation. All controllers yield similar results in terms of overall system efficiency. The emulated turbine is more responsive to turbulent inflow than the field turbine, as the model utilized to drive emulation does not account for a smoothing effect of turbulent fluctuations over the span of the fielded turbine's rotors. The turbine has a lower inertia than the demand of an isolated grid, indicating a secondary source of power with a similar frequency response is necessary if a single turbine cannot meet the entire demand. Major contributions of this work include exploration of the system time constant as an indicator of turbine dynamic response, evidence a turbine experiences system stall probabilistically, a reduced-complexity field performance characterization methodology, and demonstration of the effectiveness of electromechanical emulators at replicating turbine dynamics.

Download or read book An Evaluation of the U S Department of Energy s Marine and Hydrokinetic Resource Assessments written by National Research Council and published by National Academies Press. This book was released on 2013-04-23 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing renewable energy development, both within the United States and abroad, has rekindled interest in the potential for marine and hydrokinetic (MHK) resources to contribute to electricity generation. These resources derive from ocean tides, waves, and currents; temperature gradients in the ocean; and free-flowing rivers and streams. One measure of the interest in the possible use of these resources for electricity generation is the increasing number of permits that have been filed with the Federal Energy Regulatory Commission (FERC). As of December 2012, FERC had issued 4 licenses and 84 preliminary permits, up from virtually zero a decade ago. However, most of these permits are for developments along the Mississippi River, and the actual benefit realized from all MHK resources is extremely small. The first U.S. commercial gridconnected project, a tidal project in Maine with a capacity of less than 1 megawatt (MW), is currently delivering a fraction of that power to the grid and is due to be fully installed in 2013. As part of its assessment of MHK resources, DOE asked the National Research Council (NRC) to provide detailed evaluations. In response, the NRC formed the Committee on Marine Hydrokinetic Energy Technology Assessment. As directed in its statement of task (SOT), the committee first developed an interim report, released in June 2011, which focused on the wave and tidal resource assessments (Appendix B). The current report contains the committee's evaluation of all five of the DOE resource categories as well as the committee's comments on the overall MHK resource assessment process. This summary focuses on the committee's overarching findings and conclusions regarding a conceptual framework for developing the resource assessments, the aggregation of results into a single number, and the consistency across and coordination between the individual resource assessments. Critiques of the individual resource assessment, further discussion of the practical MHK resource base, and overarching conclusions and recommendations are explained in An Evaluation of the U.S. Department of Energy's Marine and Hydrokinetic Resource Assessment.

Download or read book Designing Optimizing and Testing of a River Hydrokinetic Prototype Turbine System for Remote Northern Communities written by Raul Vaid and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A hydrokinetic turbine extracts energy from river currents and can enable communities worldwide to establish micro-grids to address part of their base loads. Hydrokinetic turbines offer a viable solution to produce power year-round to displace diesel generation in northern communities. However, these turbines must operate in reduced winter flows and not be impacted by ice. A passive-counter-torque and river-prototype hydrokinetic turbine integrated system is presented that offers a simpler and lower-cost approach to deploy, operate and maintain hydrokinetic turbines year-round in cold climates. A 500-W river prototype designed with a 0.48 m diameter two-blade impeller is optimized, built and tested. It produces a torque of 24.44 Nm at 200 RPM for a flow velocity of 2.0 m/s. For this in-situ prototype, shrouds, winglets, and wingtips are developed and optimized to reduce the levelized cost of electricity and micro-grid performance when flow velocities are lower than the design set point of 2.0 m/s. Such off-design conditions are mainly experienced during winter seasons. Numerical simulations confirm that the winglet design maintains the design power when experiencing up to 18% reduction in velocity. Various design combinations were tested by varying component dimensions: 2,216 combinations for shrouds and 4,103 for winglets. The optimal results were achieved using the shrouds, while the winglets were found to have the advantage to prevent stalling. Testing of the prototype turbine at the Canadian Hydrokinetic Turbine Testing Centre shows that the counter-torque design selected was stable. However, using a field vacuum pump to control the ballast in the configuration tested needs to be reconsidered.

Download or read book Hydrodynamic Optimization Method and Design Code for Stall regulated Hydrokinetic Turbine Rotors written by Danny Sale and published by . This book was released on 2009 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the adaptation of a wind turbine performance code for use in the development of a general use design code and optimization method for stall-regulated horizontal-axis hydrokinetic turbine rotors. This rotor optimization code couples a modern genetic algorithm and blade-element momentum performance code in a user-friendly graphical user interface (GUI) that allows for rapid and intuitive design of optimal stall-regulated rotors. This optimization method calculates the optimal chord, twist, and hydrofoil distributions which maximize the hydrodynamic efficiency and ensure that the rotor produces an ideal power curve and avoids cavitation. Optimizing a rotor for maximum efficiency does not necessarily create a turbine with the lowest cost of energy, but maximizing the efficiency is an excellent criterion to use as a first pass in the design process. To test the capabilities of this optimization method, two conceptual rotors were designed which successfully met the design objectives.

Download or read book A Remotely Operated Hydrokinetic Turbine to Reduce the Levelized Cost of Energy of Marine Turbines written by Armin Hamta and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A novel hydrokinetic turbine system is proposed to address key commercialization challenges facing the marine energy industry. Challenges include addressing icing issues by eliminating equipment that pierce the water/air interface; reducing the levelized cost of energy by simplifying demanding deployment and retrieval procedures; and positioning the turbine in the water column to maximize annual power production. Results of the experimental test matrix shows successful operation of the scaled counter-torque mechanism which operates with a 20 cm diameter rotor and is stabilized from the reactive nature of two point masses located at opposite ends of a spoke connected to the nacelle. Static and dynamic analytical modeling, computer aided design, manufacturing, and experimental testing of the prototype is the methodology that validates the operation of the counter-torquing mechanism. The prototype turbine is tested in a laboratory water tunnel at Reynolds numbers of 94 x 10^3, 104 x 10^3, and 115 x 10^3; with the generator loads ranging from free-wheeling to 6.2 W; and available counter-torque capacity varying from 0% to 40%. The maximum power coefficient obtained during the tests is 48.3% at a rotor tip speed ratio of 4.5. This research advances the Technology Readiness Level of the proposed novel turbine system from a level one to a level four based on the U.S. Department of Energy definition for technology development.

Download or read book Synergistic Design of a Combined Floating Wind Turbine Wave Energy Converter written by Jocelyn Maxine Kluger and published by . This book was released on 2017 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offshore energy machines have great potential: higher capacity factors, more available space, and lower visual impacts than onshore machines. This thesis investigates how combining a wave energy converter (WEC) with a floating wind turbine (FWT) may produce offshore renewable energy cost savings. Attaching the WEC to the FWT greatly reduces the WEC’s steel frame, mooring lines, electric transmission lines, and siting/permitting costs, which may comprise 56% of a standalone WEC’s cost. A 5 MW FWT currently requires up to 1700 tons of platform steel and 5700 tons of ballast concrete for stabilization in the ocean. This required material may be reduced if the WEC stabilizes the FWT. This thesis addresses several challenges to designing a combined FWT-WEC. First, parameter sweeps for optimizing ocean machine performance are limited by high dimensionalities and nonlinearities, including power takeoff control and wave viscous forcing, which normally require computationally expensive time-domain simulations. This thesis develops a statistical linearization approach to rapidly compute machine dynamics statistics while accounting for nonlinearities in the frequency domain. It is verified that the statistical linearization method may capture significant dynamics effects that are neglected by the traditional Taylor series linearization approach, while computing the results approximately 100 times faster than time domain simulations. Using Morison’s equation for wave viscosity and quasi-steady blade-element/momentum theory for rotor aerodynamics, we find that viscous effects and nonlinear aerodynamics may increase the FWT motion and tower stress by up to 15% in some wind-sea states compared the the Taylor series linearized system. Second, the WEC must stabilize rather than destabilize the FWT. This thesis investigates the dynamics statistics of dierent FWT-WEC configurations using a long wavelength, structurally coupled model. It is shown that simultaneous targeted energy transfer from both the FWT and waves to the WEC when the WEC and FWT are linked by a tuned spring is unlikely. That being said, this thesis considers heave-mode oscillating water column WEC’s that are linked to the FWT platform by 4-bar linkages, so that the FWT and WEC’s are uncoupled for small heave motions and rigidly coupled in all other degrees of freedom. It is shown that this configuration allows the WEC to move with a large amplitude in its energy harvesting degree of freedom, and therefore harvest a significant amount of power without significantly increasing the FWT motion in the same direction. In the rigidly-connected modes, the WEC inertial resistance to motion must be greater than the wave forcing, as these properties are transmitted to the FWT. Third, the WEC requires power robustness in dierent sea states. Typical WEC’s require control schemes to maintain good power performance when the ocean wave dominant frequency differs from the WEC resonant frequency. This thesis introduces a nonlinearity into the WEC design that passively increases power adaptability in dierent sea states. While the optimized nonlinear WEC requires 57% more steel than the optimized linear WEC, the nonlinear WEC produces 72% more power on average, resulting in a 3% lower levelized cost of energy. Further optimization of the nonlinear WEC may find improved performance. This thesis determines that attaching a single linear hinged floating spar oscillating water column to the FWT reduces the levelized cost of energy from $0.31/kWh for the standalone system to $0.27/kWh (13%) without changing stress on the FWT tower. Attaching a single nonlinear hinged floating spar oscillating water column to the FWT reduces the levelized cost of energy to $0.26/kWh (16%) and reduces the lifetime equivalent fatigue stress on the FWT tower from 32.4 MPa to 31 MPa (5%). A 6-unit array of the nonlinear WEC’s encircling the FWT platform may generate an average of 400 kW while reducing the FWT tower stress by over 50%. In wave tank experiments, the response statistics of four dierent combined FWT-WEC configurations are measured, verifying the FWT-WEC dynamics model.

Download or read book Maximum Power Point Tracking Control of Hydrokinetic Turbine and Low speed High thrust Permanent Magnet Generator Design written by Hailong Zhou and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "River-based hydrokinetic turbine power generation systems have been studied to introduce an effective energy flow control method. Hydrokinetic turbine systems share a lot of similarities with wind turbine systems in terms of physical principles of operation, electrical hardware, and variable speed capability for optimal energy extraction. A multipole permanent magnet synchronous generator is used to generate electric power because of its ability to reach high power density and high thrust at low speed. A 3-phase diode rectifier is used to convert AC power from the generator into DC power and a boost converter is used to implement energy flow control. On the load side, an electronic voltage load is used for test purposes to simulate a constant DC bus voltage load, such as a battery. A dynamic model of the entire system is developed and used to analyze the interaction between the mechanical structure of water turbine and electrical load of the system, based on which a maximum power point tracking control algorithm is developed and implemented in the boost converter. Simulation and experimental results are presented to validate the proposed MPPT control strategy for hydrokinetic turbine system. Similar to the wind turbine system, hydrokinetic turbine system usually requires a gear box to couple the turbine and the generator because the operating speed range for the hydrokinetic turbine is much lower than the operating speed range for most PMSGs. However, the gear box coupling adds additional transmission power losses. Therefore a high-thrust low-speed permanent magnet synchronous generator is designed to couple with the water turbine without a gear box"--Abstract, leaf iii

Download or read book Development of a Control Co Design Modeling Tool for Marine Hydrokinetic Turbines Preprint written by and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the ongoing and planned development of the software package CT-Opt (Current/Tidal Optimization), a control co-design modeling tool for marine hydrokinetic turbines. The commercialization of these turbines has faced significant challenges due to the complex, multidisciplinary nature of their design and the extreme environmental conditions of their operation. This project aims to create a modeling tool that will enable the efficient design of robust, cost-competitive hydrokinetic turbine systems. Rather than using traditional optimization methods, CT-Opt combines multiple models across a range of fidelities to enable coupled optimization of the system design and system controller via a control co-design approach. With this method, the parameters that affect system performance are considered more comprehensively at every stage of the design process. The lowest-fidelity, frequency-domain model called by CT-Opt is RAFT (Response Amplitudes of Floating Turbines), which was originally developed by the National Renewable Energy Laboratory (NREL) to model response amplitudes of floating offshore wind turbines. The highest-fidelity, time-domain model is OpenFAST, which was developed by NREL for land-based and offshore wind turbines. As part of the CT-Opt project, new functionalities will be added to RAFT and OpenFAST to enable the accurate simulation of fixed and floating marine hydrokinetic turbines. In addition to expanding the capabilities of RAFT and OpenFAST, new midfidelity models will be developed. These models will be based on RAFT and OpenFAST and will consist of linearized, state-space models derived from the fully coupled, nonlinear OpenFAST equations and derivative function surrogate models that approximate the nonlinear system behavior. Each model will be coupled with controllers to allow control co-design methods to be applied both within models and across fidelity levels, enabling efficient system optimization.

Download or read book Modeling and Optimizing Hydrokinetic Turbine Arrays Using Numerical Simulations written by Olivier Gauvin Tremblay and published by . This book was released on 2021 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to plan a river hydrokinetic turbine array deployment and to maximize its energy extraction, turbine array simulations are often carried out. However, in a context where tens of turbines are deployed, it is unthinkable to simulate the complete rotating geometry of every turbine. It is therefore necessary to use simplified models that reproduce accurately the turbines and that incorporate all the main interactions taking place in a turbine array, namely the turbine-wake interactions, the blockage effects and the interaction with the resource. The Effective Performance Turbine Model (EPTM) is a suitable tool in that sense, allowing to test and analyze a large amount of different array configurations at a low computational cost. Although the EPTM has been developed to serve as a tool for array analysis, it has only been tested up to now in a uniform flow with a low turbulence level. For this reason, the EPTM has been validated and adapted in this work to ensure a proper and reliable use in river array flow conditions. Herein, the efforts has been mainly put on a cross-flow turbine (CFT) technology. First, a numerical methodology has been developed to reproduce river flow conditions and array flow conditions, which include shear, large-scale temporal fluctuations and (modeled) turbulence. Following 3D blade-resolved turbine simulations, it is found that a turbine operating in those conditions sees a reduction of its performance, especially when the shear aspect is present. However, it turns out that the effective drag coefficient remains essentially unchanged, allowing to use the same local effective force coefficient distribution in every situation. Moreover, although the effective power coefficient appears to be lower than for a turbine in idealized flow conditions, it does not vary depending of the type of perturbation and its decrease is small under free-surface conditions. This is important for the use of the EPTM, since the simplified model is based on this assumption. Multiple comparisons between EPTM and blade-resolved turbine simulations in river/array flow conditions have confirmed that the EPTM-CFT is always able to predict accurately the performances of the turbines and to reproduce their mean wake with a high degree of reliability. Following this validation procedure, a series of turbine array simulations have been conducted using the EPTM-CFT. Assuming a turbulent flow environment, many vertical-axis turbine array configurations have been tested to study more precisely the effect of local blockage, lateral and longitudinal spacing, array staggering and direction of rotation on turbine performance. Results have shown that all aspects of blockage, local and global, must be considered simultaneously with the possibility of turbine-wake interaction, especially when the turbines generate a wake that deflects sideways down-stream. The latter aspect could play an important role in determining whether or not the array should be staggered. For a multiple-row array, this aspect also affects the relevance of the different array parameters used. Indeed, in this context, the lateral spacing becomes more meaningful than the local blockage value. To help decide on the optimal lateral and longitudinal spacing to set within an array, a new parameter has been proposed: the marginal power per turbine. As many economic variables can come into play, this parameter helps quantifying the benefit of adding rows or columns of turbines in comparison to the already installed power. Finally, it is possible, for an identified optimal turbine array, to assess its impact on the resource. Based on an actual river site, a realistic simulation of a turbine array in river has been performed using the methodology previously developed. The simulation results, compared with the results of more simplified simulations, have pointed out that an appropriate channel geometry and an accurate inflow velocity distribution are essential to obtain reliable array performances. Although it arises that taking into account the free surface has negligibly affected the array performances and the water level upstream for the case considered, it remains that the assessment of the impact on the resource is always relevant since the rise in the water level can be larger if the blockage ratio or the Froude number are higher.

Download or read book Passive Pitch Control in Marine Hydrokinetic Turbine Blades written by Ramona Brockman Barber and published by . This book was released on 2014 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: Green and renewable energy technologies are becoming more and more necessary as demand for energy grows exponentially around the world. Recently, there has been increased interest in using marine hydrokinetic turbines to generate energy from ocean currents and tidal flows. The blades of these turbines are slender and are subjected to large, dynamic fluid forces; for that reason they are typically constructed from fiber-reinforced composites. The bend-twist deformation coupling behavior of these materials can be hydroelastically tailored such that the pitch angle of the blades will passively change to adapt to the surrounding flow, creating an instantaneous reaction that can improve system performance over the expected life of the turbine. Potential benefits of this passive control mechanism include increased lifetime power generation, reduced hydrodynamic instabilities, and improved load shedding and structural performance. There are practical concerns, however, that increase the complexity of the design of these bend-twist coupled blades. Large inflow variations in viable locations for turbine implementation combined with system component limitations such as restrictions on the generator and maximum rotational speed require consideration of practical and site-specific constraints. Using a previously validated boundary element method-finite element method solver, this work presents a numerical investigation into the capabilities of passive pitch adaptation under both instantaneous and long-term variable amplitude loading to better describe potential benefits while considering practical design and operational restrictions.

Download or read book Design and Critical Performance Evaluation of Horizontal Axis Hydrokinetic Turbines written by Suchi Subhra Mukherji and published by . This book was released on 2010 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The current work discusses the hydrodynamic performance of horizontal axis hydrokinetic turbines (HAHkT) under different turbine geometries and flow conditions. Hydrokinetic turbines are a class of zero-head hydropower systems which utilize kinetic energy of flowing water to drive a generator. However, such turbines often suffer from low-efficiency. A detailed computational fluid dynamics study was performed using a low-order k-[omega] SST (Shear Stress Transport) turbulence model to examine the effect of each of tip-speed ratio, solidity, angle of attack and number of blades on the performance of small HAHkTs with a power capacity of 10 kW. The numerical models (both two-dimensional and three-dimensional) developed for these purposes were validated with blade element momentum theory. The two-dimensional numerical models suggest an optimum angle of attack that maximizes lift as well as lift to drag ratio thereby yielding the maximum power output. In addition, our three-dimensional model is used to estimate optimum turbine solidity and blade numbers that produces maximum power coefficient at a given tip speed ratio. Furthermore, the axial velocity deficit downstream of the turbine rotor provides quantitative details of energy loss suffered by each turbine at ambient flow conditions. The velocity distribution provides confirmation of the stall-delay phenomenon that occurs due to the rotation of the turbine. In addition, it provides further verification of optimum tip speed ratio corresponding to maximum power coefficient obtained from the solidity analysis"--Abstract, leaf iii.

Download or read book Optimization and Computational Fluid Dynamics written by Dominique Thévenin and published by Springer Science & Business Media. This book was released on 2008-01-08 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: The numerical optimization of practical applications has been an issue of major importance for the last 10 years. It allows us to explore reliable non-trivial configurations, differing widely from all known solutions. The purpose of this book is to introduce the state-of-the-art concerning this issue and many complementary applications are presented.

Download or read book Modelling and Optimization of Wave Energy Converters written by Dezhi Ning and published by CRC Press. This book was released on 2022-07-28 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wave energy offers a promising renewable energy source, however, technologies converting wave energy into useful electricity face many design challenges. This guide presents numerical modelling and optimization methods for the development of wave energy converter technologies, from principles to applications. It covers the development status and perspectives of wave energy converter systems; the fundamental theories on wave power absorption; the modern wave energy converter concepts including oscillating bodies in single and multiple degree of freedom and oscillating water column technologies; and the relatively hitherto unexplored topic of wave energy harvesting farms. It can be used as a specialist student textbook as well as a reference book for the design of wave energy harvesting systems, across a broad range of disciplines, including renewable energy, marine engineering, infrastructure engineering, hydrodynamics, ocean science, and mechatronics engineering. The Open Access version of this book, available at www.routledge.com has been made available under a Creative Commons Attribution-Non Commercial-No Derivatives 4.0 license.