Effect of Blade Diameter on the Performance of Horizontal-Axis Ocean Current Turbine (original) (raw)
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Sustainability
Several different designs and prototypes of ocean current turbines have been tested over recent years. For every design test, emphasis is given to achieving an optimum power output from the flow. In this study, the performance of a Horizontal Axis Ocean Current Turbine (HAOCT) has been investigated using three-dimensional Computational Fluid Dynamics (CFD) simulations for three cases, namely, (1) a turbine without a deflector, (2) a turbine with a deflector, and (3) a turbine with a deflector operating at a higher fluid depth. The turbine design was modeled in DesignModeler software and simulations were carried out in commercial CFD software Flow-3D. The Torque Coefficient (Cm) and Power Coefficient (Cp) for the turbine have been investigated for a certain range of Tip-Speed Ratios (TSRs) in a flow velocity of 0.7 m/s. Furthermore, comparisons have been made to demonstrate the effect of the deflector on the performance of the turbine and the influence of a higher fluid pressure on t...
Performance Prediction of Horizontal Axis Marine Current Turbines
In this study, hydrodynamic performance of a 400 mm diameter horizontal axis marine current turbine model was tested in a cavitation tunnel with 1.21 m x 0.8 m cross-section for over a range of tip speed ratios. Torque and thrust data, as well as cavitation visualizations, for certain operating conditions were acquired. Experimental results indicated that the turbine can be exposed to significant amount of sheet and cloud cavitation over the blades along with vortex cavitation at the blade tips. Inception and distribution of cavitation along the blades of the model turbine were then modelled numerically for design operating conditions using a vortex lattice method. The method was also applied to a turbine tested previously and obtained results were compared with the data available. The comparison between simulation results and experimental data showed a slight difference in terms of span-wise extent of the cavitation region. The cloud and tip vortex cavity observed in experiments cannot be modelled due to the fact that the VLM lacks the ability to predict such types of cavitation. Notwithstanding, the use of such prediction methods can provide a reasonably accurate approach to estimate, therefore take the hydrodynamic effects of cavitation into account in design and analysis of marine current turbines.
2002–2012: 10 Years of Research Progress in Horizontal-Axis Marine Current Turbines
Energies, 2013
Research in marine current energy, including tidal and ocean currents, has undergone significant growth in the past decade. The horizontal-axis marine current turbine is one of the machines used to harness marine current energy, which appears to be the most technologically and economically viable one at this stage. A number of large-scale marine current turbines rated at more than 1 MW have been deployed around the World. Parallel to the development of industry, academic research on horizontal-axis marine current turbines has also shown positive growth. This paper reviews previous research on horizontal-axis marine current turbines and provides a concise overview for future researchers who might be interested in horizontal-axis marine current turbines. The review covers several main aspects, such as: energy assessment, turbine design, wakes, generators, novel modifications and environmental impact. Future trends for research on horizontal-axis marine current turbines are also discussed.
Design of Ocean Current Blade Turbine 100 kW using Hydrodynamics Simulation Approach
Advanced Research in Fluid Mechanics and Thermal Sciences, 2023
National electricity consumed continues to rise by up to 6.4 % per year, which are not comparable with the availability of fossil fuels as a primary energy coal-fired power plant in Indonesia. Utilization of ocean energy in particular flow energy has performed as one of the primary energy options. Tides are responsible for the renewable energy of ocean currents. Changes in flow velocity of ocean water due to the ups and downs of ocean water can be used as the primary energy to drive turbines and generate electricity. This study investigates the ocean current power plant in Indonesia that relates to the characteristics of the ocean current. The data used for this research belonged to R&D Center Marine Geology (PPPGL) from ocean current data in the Toyapakeh, Pantar, Larantuka, Molo, Boleng and Gam strait. This study looked at both the technical and socioeconomic aspects of the six locations mentioned above. Larantuka strait had the greatest potential for ocean currents in the strait. The turbine was designed using Computational Fluid Dynamics (CFD), with a capacity of 100 kW for the Horizontal Axis turbine. The findings demonstrated that the turbine design could produce electrical energy at low ocean current speeds (cut-in speed) of 0.3 m/s, and that the rotor power generated at ocean current speeds of 2.2 m/s approached the design capacity of 100 kW.
An Experimental Investigation of Passive Variable-Pitch Vertical-Axis Ocean Current Turbine
ITB Journal of Engineering Science, 2011
Vertical-axis hydrokinetic turbines with fixed pitch blades typically suffer from poor starting torque, low efficiency and shaking due to large fluctuations in both radial and tangential force with azimuth angle. Maximizing the turbine power output can be achieved only if the mechanism of generation of the hydrodynamic force on the blades is clearly identified and tools to design high-performance rotors are developed. This paper describes an initial experimental investigation to understand more of the performance on vertical-axis turbine related to the effect of fixed-pitch and passive variable-pitch application using airfoil NACA 0018. Comparative analysis according to aspects of rotation and tip speed ratios was discussed. Information regarding the changes of foil position in passive variable-pitch during rotation at a limited range of flow velocity variations test was obtained and analyzed.
Ocean Current Turbine Blade Performance Prediction using the Blade Element Theory
2015
Optimal Design of the ocean current turbine requires analysis of the blade performance to find answer to the question that at specified speed of the ocean current how much torque will produce by the blade. This thesis presents that blade element theory analysis of the ocean current turbine blade. The lift, drag and torque calculations are the important parameters for the blade performance prediction. This paper discussed the blade element theory for the prediction of the lift, drag, torque, theoretical, actual power, and coefficient of power for the NACA 44xx ocean current turbine blade. The length of the blade is 3 meter and is rotating with 24 RPM. The NACA 44xx airfoils coefficients of lift and drag are used for the calculation of lift and drag. The ocean current speed is assumed to be 1.7 m/sc and the ocean water density is 1025 kg/m.
Hydrodynamic Analysis and Design of Marine Current Turbine Blades
2016
April 10-15, 2016 Abstract In this paper, two design procedures of the marine current turbine blade geometries are presented. The first one is similar to the propeller design method, the lifting line method is used for the design of the optimum circulation distribution, and the lifting surface method is then adopted for the blade geometry design. The second design procedure uses Genetic Algorithm method to design the turbine blade geometry. Hydrodynamic performances of the marine current turbine are then computed and analyzed by the potential flow boundary element method and the viscous flow RANS method. Two design examples, including a 20kw floating type current turbine, are demonstrated in the paper, and the design results show the geometries designed by both methods satisfy the design goal; however, the geometry designed by Genetic Algorithm method has a better result. It is believed that both methods are applicable for the current turbine blade designs. .
Hydrodynamic consideration in ocean current turbine design
Journal of Hydrodynamics, 2016
Ocean currents are one of important resources of ocean energy. Although it is not widely harnessed at present, ocean current power has a vital potential for future electricity generation. In fact, several turbine systems have been proposed in the world. In the present, we consider what factors should be considered in designing the system from the perspective of hydrodynamics. As an example, a floating Kuroshio turbine system which is under development in Taiwan is employed to serve as the case study. The system consists of five major parts; i.e. a foil float which can be employed to adjust the system submergence depth, a twin contrarotating turbine system for taking off the current energy, two nacelles housing power generators, a cross beam to connect two nacelle-and-turbine systems, and two vertical support to connect the foil float and the rest of the system.
— This work presents a numerical simulation of a Vertical Axis Marine Current Turbines (VAMCT) in both steady and unsteady current velocities. Three different turbines were examined in this study in order to investigate the relationship between the current fluctuation frequency, the number of turbine blades and turbine frequency. Three, four and five blades turbines were numerically simulated. Fluent is used to solve the 2-D model using the time-accurate incompressible Unsteady Reynolds-averaged Navier-Stokes (URANS) equation with k-ω SST turbulence mode. The simulation results showed that there existed a significant relationship between the number of turbine blades, the turbine Tip Speed Ratio and the current fluctuation frequency. In an unsteady current the increase in the number of blades led to a reduction in the turbine's instability; however it might not increase the power performance especially at high TSR..
Efficiency Assessment of an Experimental Ocean Current Turbine Generator
This document presents the experimentally determined power generation efficiency for the drive-train and motor of a 20 kW experimental ocean current turbine. This efficiency assessment was performed using a custom designed dynamometer and covered much of the generator's expected operating range. These measurements are used with numerically modeled rotor performance to predict the overall efficiency of the ocean current turbine when converting kinetic energy flux to electric power.