Influence of blade numbers on start-up performance of vertical axis tidal current turbines

In recent years, tidal current energy has gained wide attention for its abundant resource and environmentally friendly production. This study focuses on analyzing dynamic behavior of a three-bladed vertical axis tidal current turbine. The multibody dynamics code MBDyn is used in the numerical simulation. It performs the integrated simulation and analysis of nonlinear mechanical, aeroelastic, hydraulic and control problems by numerical integration. In this study, tidal current turbine is idealized as an assembly of flexible beams including axis of rotation, arms and blades. We firstly conduct a modal analysis on the tidal current turbine and validate the model with the results obtained by ANSYS. The natural frequencies of blades with different size parameters are compared and the corresponding mode shapes are presented. Next, a parametric study was performed to investigate the effect of internal force on the dynamic response. It is concluded that the proposed method is accurate and efficient for structural analysis of tidal current turbine and this flexible multibody model can be used in the fluid-structure-interaction analysis in the future.

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Numerical study on energy-converging efficiency of the ducts of vertical axis tidal current turbine in restricted water

Ocean Engineering ◽

10.1016/j.oceaneng.2020.107320 ◽

2020 ◽

Vol 210 ◽

pp. 107320 ◽

Cited By ~ 1

Author(s):

Wang Hua-Ming ◽

Qu Xiao-Kun ◽

Chen Lin ◽

Tu Lu-Qiong ◽

Wu Qiao-Rui

Keyword(s):

Tidal Current ◽

Numerical Study ◽

Vertical Axis ◽

Tidal Current Turbine ◽

Current Turbine

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Study of the hydrodynamic derivatives of vertical-axis tidal current turbines in surge motion

Renewable Energy ◽

10.1016/j.renene.2016.04.074 ◽

2016 ◽

Vol 96 ◽

pp. 366-376 ◽

Cited By ~ 8

Author(s):

Qihu Sheng ◽

Fengmei Jing ◽

Liang Zhang ◽

Nianfu Zhou ◽

Shuqi Wang ◽

...

Keyword(s):

Tidal Current ◽

Vertical Axis ◽

Hydrodynamic Derivatives ◽

Derivatives Of

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Vortex Analytical Model of a Circulation Controlled Vertical Axis Wind Turbine

ASME 2009 3rd International Conference on Energy Sustainability, Volume 2 ◽

10.1115/es2009-90348 ◽

2009 ◽

Cited By ~ 1

Author(s):

Jay P. Wilhelm ◽

Chad C. Panther ◽

Franz A. Pertl ◽

James E. Smith

Keyword(s):

Wind Turbine ◽

Analytical Model ◽

Vertical Axis ◽

Circulation Control ◽

Vertical Axis Wind Turbine ◽

Trailing Edge ◽

Vortex Interactions ◽

Vortex Model ◽

Aspect Ratios ◽

Start Up

A possible method for modeling a Circulation Controlled - Vertical Axis Wind Turbine (CC-VAWT) is a vortex model, based upon the circulation of a turbine blade. A vortex model works by continuously calculating the circulation strength and location of both free and blade vortices which are shed during rotation. The vortices’ circulation strength and location can then be used to compute a velocity at any point in or around the area of the wind turbine. This model can incorporate blade wake interactions, unsteady flow conditions, and finite aspect ratios. Blade vortex interactions can also be studied by this model to assist designers in the avoidance of adverse turbulent operational regions. Conventional vertical axis wind turbine power production is rated to produce power in an operating wind speed envelope. These turbines, unless designed specifically for low speed operation require rotational start-up assistance. The VAWT blade can be augmented to include circulation control capabilities. Circulation control can prolong the trailing edge separation and can be implemented by using blowing slots located adjacent to a rounded trailing edge surface; the rounded surface of the enhanced blade replaces the sharp trailing edge of a conventional airfoil. Blowing slots of the CC-VAWT blade are located on the top and bottom trailing edges and are site-controlled in multiple sections along the span of the blade. Improvements in the amount of power developed at lower speeds and the elimination or reduction of start-up assistance could be possible with a CC-VAWT. In order to design for a wider speed operating range that takes advantage of circulation control, an analytical model of a CC-VAWT would be helpful. The primary function of the model is to calculate the aerodynamic forces experienced by the CC-VAWT blade during various modes of operation, ultimately leading to performance predictions based on power generation. The model will also serve as a flow visualization tool to gain a better understanding of the effects of circulation control on the development and interactions of vortices within the wake region of the CC-VAWT. This paper will describe the development of a vortex analytical model of a CC-VAWT.

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A Towing Test of a Floating Type VAMT With Cycloidal Pitch-Controlled Blades

Volume 6: Ocean Space Utilization ◽

10.1115/omae2018-77443 ◽

2018 ◽

Author(s):

Tomoki Ikoma ◽

Hiroaki Eto ◽

Koichi Masuda ◽

Atsuhiro Oguchi

Keyword(s):

Control System ◽

Current Velocity ◽

Tidal Current ◽

Vertical Axis ◽

Floating Structure ◽

Current Generation ◽

Variable Pitch ◽

Pitch Control ◽

Tidal Current Velocity ◽

Vertical Axis Turbine

Sea areas around the Japanese Islands which is feasible for tidal current generation are not a lot because sea sites where tidal current velocity is above 2.0 m/s are a few. We can find such sea sites at a west side of the Kyushu Island especially. However, we would earn electrical energy to be generated if it is able to generate electricity long time using around 1.0 m/s in current velocity. A vertical axis turbine should be better than horizontal axis types because VATs can take relatively higher torque. It is very useful that we can set and control a marine turbine to be higher performance in various current velocity. The present study introduce variable pitch-control system to a vertical axis turbine for tidal current generation. The pitch-control system adapts a cycloidal mechanism so that to vary pitch angle of turbine blades is conducted mechanically. The study developed a vertical axis marine turbine with cycloidal pitch-controlled three blades which was based on previous studies and experimental data. The diameter of the turbine is 1.0 m, length of a blade is 1.3 m. The turbine was set on a floating structure in order to carry out towing tests at a sea. We obtained several kinds of data from the towing tests, which were turbine torque, the number of rotation of the turbine, output power from an electrical generator and acceleration of the floating structure. As a result, the turbine made 50 W power from the generator. Although the PTO was not so large, the pitch-control was effective very much. Some issues were found at the same time. We need to consider and develop more useful gears, assemble methods to be feasible of variable pitch system.

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Numerical Investigation of Aerodynamic Performance of a Three-Bladed Vertical Axis Wind Turbine

Volume 5: Energy Systems Analysis, Thermodynamics and Sustainability; NanoEngineering for Energy; Engineering to Address Climate Change, Parts A and B ◽

10.1115/imece2010-39267 ◽

2010 ◽

Author(s):

Alexandrina Untaroiu ◽

Lydia R. Barker ◽

Houston G. Wood ◽

Robert J. Ribando ◽

Paul E. Allaire

Keyword(s):

Wind Turbine ◽

Cfd Simulation ◽

Vertical Axis ◽

Operating Speed ◽

University Of Virginia ◽

Vertical Axis Wind Turbine ◽

Start Up ◽

Ansys Cfx ◽

Turbine Design ◽

The University

As a pollution free source of energy, wind is among the most popular and fastest growing forms of electricity generation in the world. Compared to their horizontal axis counterparts, vertical axis wind turbines have lagged considerably in development and implementation. The University of Virginia Rotating Machinery and Controls laboratory has undertaken a systematic review of vertical axis wind turbine design in order to address this research gap, starting with establishment of a methodology for vertical axis wind turbine simulation using ANSYS CFX. A 2D model of a recently published Durham University vertical axis wind turbine was generated. Full transient CFD simulations using the moving mesh capability available in ANSYS-CFX were run from turbine start-up to operating speed and compared with the experimental data in order to validate the technique. A scalable k-ε turbulence model transient CFD simulation has been demonstrated to accurately predict vertical axis wind turbine operating speed within 12% error using a two-dimensional structured mesh in conjunction with a carefully specified series of boundary conditions.

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Vertical-axis tidal-current generators and the Pentland Firth

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1243/09576509jpe295 ◽

2007 ◽

Vol 221 (2) ◽

pp. 181-199 ◽

Cited By ~ 23

Author(s):

S. H. Salter ◽

J. R M. Taylor

Keyword(s):

Tidal Current ◽

Vertical Axis

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Research on the end-plate for vertical axis tidal current turbine

Proceedings of the Institution of Mechanical Engineers Part M Journal of Engineering for the Maritime Environment ◽

10.1177/1475090216681259 ◽

2016 ◽

Vol 231 (3) ◽

pp. 750-759

Author(s):

Yu Xie ◽

Haigui Kang ◽

Bing Chen ◽

Wei Guo

Keyword(s):

Tidal Current ◽

Vertical Axis ◽

End Plate ◽

Tidal Current Turbine ◽

Current Turbine

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

Volume 5: Ocean Space Utilization; Polar and Arctic Sciences and Technology; The Robert Dean Symposium on Coastal and Ocean Engineering; Special Symposium on Offshore Renewable Energy ◽

10.1115/omae2007-29708 ◽

2007 ◽

Cited By ~ 4

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.

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