A Procedure for Predicting Energy From a Tidal Turbine Farm

2007 ◽  
Author(s):  
Ye Li ◽  
Sander M. Calisal
Keyword(s):  
Power Generation ◽  
Tidal Current ◽  
Companion Paper ◽  
Dominant Factor ◽  
Systematic Analysis ◽  
Power Cost ◽  
Factors Affecting ◽  
Tidal Turbine ◽  
Tidal Current Turbine ◽  
A Site

A tidal current turbine is a device for harnessing energy from tidal current. A group of tidal current turbines, distributed schematically at a site, is called a tidal turbine farm. A tidal turbine farm has to be located in a confined channel or a straight where consistent high-velocity tidal current flow is available for the cost-effectiveness concern. This narrow geographical condition poses challenges for turbine farm planners to distribute turbines strategically. Turbines’ distribution in a farm affects power generation efficiency and the resultant tidal unit power cost. In this paper, we propose a procedure for predicting energy generation from a tidal turbine farm by investigating the optimal distribution of turbines at a given site. The objective of optimizing the turbines distribution is to maximize the power output efficiency. To fulfill this, we conducted a systematic analysis on power generation from a tidal turbine farm to identify the key factors affecting the optimal tidal turbines distribution with an emphasis on the turbines’ hydrodynamics analysis and briefed the turbine working principle. As a companion paper to Li and Calisal (2007) which discusses the principle of a stand alone turbine, turbine configuration and interactions (i.e. angle of attack, turbine relative distance and turbine size) are extended here. The main assumption of this discussion is that vortex shedding impact is the dominant factor causing the turbine efficiency loss. Considering the turbine design principle, a simplified relationship between turbines distribution and turbine farm efficiency is formulated. Then, numerical simulation results are presented for a given site in British Columbia together with extended general solution.

Comparison of Tidal Current Turbine Designs in Several High Speed Locations Around the United States

2015 ◽  
Author(s):  
Mohammed S. Mayeed ◽  
Golam M. Newaz ◽  
Dallin Hall ◽  
Davison Elder
Keyword(s):  
United States ◽  
Power Generation ◽  
Gulf Stream ◽  
Tidal Current ◽  
The United States ◽  
Simulation Software ◽  
Tidal Current Energy ◽  
Tidal Current Turbine ◽  
Current Energy ◽  
Current Turbine

Tidal current energy is regarded as one of the most promising alternative energy resources for its minimal environmental footprint and high-energy density. The device used to harness tidal current energy is the tidal current turbine, which shares similar working principle with wind turbines. The high load factors resulting from the fluid properties and the predictable resource characteristics make marine currents particularly attractive for power generation. There is a paucity of information regarding various key aspects of system design encountered in this relatively new area of research. Not much work has been done to determine the characteristics of turbines running in water for kinetic energy conversion even though relevant work has been carried out on ship’s propellers, wind turbines and on hydro turbines. None of these three well established areas of technology completely overlap with this new field so that gaps remain in the state of knowledge. A tidal current turbine rated at 1–3 m/s in water can result in four times as much energy per year/m2 of rotor swept area as similarly rated power wind turbine. Areas with high marine current flows commonly occur in narrow straits, between islands, and around. There are many sites worldwide with current velocities around 2.5 m/s, such as near the UK, Italy, the Philippines, and Japan. In the United States, the Florida Current and the Gulf Stream are reasonably swift and continuous currents moving close to shore in areas where there is a demand for power. In this study tidal current turbines are designed for several high tidal current areas around USA for a tidal current speed range from 1 m/s to 2.5 m/s. Several locations around USA are considered, e.g. the Gulf Stream; Mississippi River, St. Clair’s river connecting Lake Huron to Lake St. Clair’s; Colorado River within Cataract Canyon etc. Tidal current turbines can be classified as either horizontal or vertical axis turbines. In this study several designs from both the classifications are considered and modeled using SolidWorks. Hydrodynamic analysis is performed using SolidWorks Flow simulation software, and then optimization of the designs is performed based on maximizing the starting rotational torque and ultimate power generation capacity. From flow simulations, forces on the tidal current turbine blades and structures are calculated, and used in subsequent stress analysis using SolidWorks Simulation software to confirm structural integrity. The comparative results from this study will help in the systematic optimization of the tidal current turbine designs at various locations.

Preliminary Results of a Vortex Method for Stand-Alone Vertical Axis Marine Current Turbine

2007 ◽  
Author(s):  
Ye Li ◽  
Sander M. Calisal
Keyword(s):  
Wind Turbine ◽  
Tidal Current ◽  
Vortex Method ◽  
Vertical Axis ◽  
Small Scale ◽  
Discrete Vortex ◽  
Analysis And Design ◽  
Tidal Turbine ◽  
Tidal Current Turbine ◽  
Current Turbine

Tidal power technology has been dwarfed once to take hold in the late 1970’s, because the early generations were expensive at small scale and some applications (such as barrages) had negative environmental impacts. In a similar working manner as a wind turbine, a tidal current turbine has been recognized as a promising ocean energy conversion device in the past two decades. However, the industrialization process is still slow. One of the important reasons is lack of comprehensive turbine hydrodynamics analysis which can not only predict turbine power but also assess impacts on the surrounding areas. Although a lot can be learned from the marine propeller or the wind turbine studies, a systematic hydrodynamics analysis on a vertical axis tidal current turbine has not been reported yet. In this paper, we employed vortex method to calculate the performance of stand-alone vertical axis tidal turbine in term of power efficiency, torque and forces. This method focuses on power prediction, hydrodynamics analysis and design, which can provide information for turbines distribution planning in a turbine farm and other related studies, which are presented in Li and Calisal (2007), a companion paper in the conference. In this method, discrete vortex method is the core for numerical calculation. Free vortex wake structure, nascent vortex and vortex decay mechanism are discussed in detail. Good agreements in turbine efficiency comparison are obtained with both the newly-designed tidal turbine test in a towing tank and early wind turbine test.

scholarly journals Structural Design of a Horizontal-Axis Tidal Current Turbine Composite Blade

2011 ◽  
Author(s):  
Gunjit S. Bir ◽  
Michael J. Lawson ◽  
Ye Li
Keyword(s):  
Structural Design ◽  
Tidal Current ◽  
Center Of Mass ◽  
Tidal Flow ◽  
Composite Blade ◽  
Extreme Loads ◽  
Tidal Turbine ◽  
Laminate Theory ◽  
Tidal Current Turbine ◽  
Current Turbine

This paper describes the structural design of a tidal turbine composite blade. The structural design is preceded by two steps: hydrodynamic design and determination of extreme loads. The hydrodynamic design provides the chord and twist distributions along the blade length that result in optimal performance of the tidal turbine over its lifetime. The extreme loads, i.e. the extreme flap and edgewise loads that the blade would likely encounter over its lifetime, are associated with extreme tidal flow conditions and are obtained using a computational fluid dynamics (CFD) software. Given the blade external shape and the extreme loads, we use a laminate-theory-based structural design to determine the optimal layout of composite laminas such that the ultimate-strength and buckling-resistance criteria are satisfied at all points in the blade. The structural design approach allows for arbitrary specification of the chord, twist, and airfoil geometry along the blade and an arbitrary number of shear webs. In addition, certain fabrication criteria are imposed, for example, each composite laminate must be an integral multiple of its constituent ply thickness. In the present effort, the structural design uses only static extreme loads; dynamic-loads-based fatigue design will be addressed in the future. Following the blade design, we compute the distributed structural properties, i.e. flap stiffness, edgewise stiffness, torsion stiffness, mass, moments of inertia, elastic-axis offset, and center-of-mass offset along the blade. Such properties are required by hydro-elastic codes to model the tidal current turbine and to perform modal, stability, loads, and response analyses.

scholarly journals Effect of a Support Tower on the Performance and Wake of a Tidal Current Turbine

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1059
Author(s):  
Zia Ur Rehman ◽  
Saeed Badshah ◽  
Amer Farhan Rafique ◽  
Mujahid Badshah ◽  
Sakhi Jan ◽  
...  
Keyword(s):  
Tidal Current ◽  
Tidal Energy ◽  
Coefficient Of Performance ◽  
Speed Ratio ◽  
Cfd Simulations ◽  
Ansys Cfx ◽  
Tidal Turbine ◽  
Computational Fluid Dynamics Cfd ◽  
Tidal Current Turbine ◽  
Current Turbine

Tidal energy is one of the major sources of renewable energy. To accelerate the development of tidal energy, improved designs of Tidal Current Turbine (TCT) are necessary. The effect of tower on performance and wake of TCT is investigated using Computational Fluid Dynamics (CFD) simulations. Transient analysis with transient rotor stator frame change model and shear stress transport turbulence model are utilized in ANSYS CFX. An experimentally validated numerical model with full scale tidal turbine with a blockage ratio of 14.27% and Tip Speed Ratio (TSR) 4.87 is used to simulate the effect of different tower diameters on performance and wake. The effect of different tower diameters is quantified in terms of coefficient of performance (CP). Coefficient of performance for a 3.5 m tower diameter is 0.472 which is followed by 3, 2.5 and 2 m with coefficients of performance of 0.476, 0.478 and 0.476 respectively. Similarly, the coefficient of thrust (CT) on the rotor for 3.5 m tower diameter is 0.902, for 3 m diameter 0.906 and for 2.5 and 2 m diameters are 0.908 and 0.906 respectively.

scholarly journals A Reliability Based Model for Wind Turbine Selection

2013 ◽  
Vol 2 (2) ◽  
pp. 69-74 ◽  
Author(s):  
A.K. Rajeevan ◽  
P.V. Shouri ◽  
Usha Nair
Keyword(s):  
Power Generation ◽  
Wind Speed ◽  
Wind Turbine ◽  
Wind Power ◽  
Point Of View ◽  
Cube Root ◽  
Mathematical Relationship ◽  
Turbine Generator ◽  
Wind Turbine Generator ◽  
A Site

A wind turbine generator output at a specific site depends on many factors, particularly cut- in, rated and cut-out wind speed parameters. Hence power output varies from turbine to turbine. The objective of this paper is to develop a mathematical relationship between reliability and wind power generation. The analytical computation of monthly wind power is obtained from weibull statistical model using cubic mean cube root of wind speed. Reliability calculation is based on failure probability analysis. There are many different types of wind turbinescommercially available in the market. From reliability point of view, to get optimum reliability in power generation, it is desirable to select a wind turbine generator which is best suited for a site. The mathematical relationship developed in this paper can be used for site-matching turbine selection in reliability point of view.

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