scholarly journals Hydrodynamic Performance Analysis of the Vertical Axis Twin-Rotor Tidal Current Turbine

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1694 ◽  
Author(s):  
Yong Ma ◽  
Chao Hu ◽  
Yulong Li ◽  
Lei Li ◽  
Rui Deng ◽  
...  
Keyword(s):  
Power Output ◽  
Tidal Current ◽  
Vertical Axis ◽  
Hydrodynamic Performance ◽  
Relative Distance ◽  
Output Efficiency ◽  
Simulation Results ◽  
Tidal Current Turbine ◽  
Current Turbine ◽  
Twin Rotor

The goal of this manuscript is to investigate the influence of relative distance between the twin rotors on the hydrodynamic performance of the vertical axis twin-rotor tidal current turbine. Computational fluid dynamics (CFD) simulations based on commercial software ANSYS-CFX have been performed to enhance the understanding of interactions between the twin-rotors. The interactions between the twin rotors are known to have increased the power output efficiency as a whole, and it is, therefore, of great significance to undertake deeper research. The simulation results are found to be consistent with similar research results in the literature in some aspects. The simulation results of stand-alone turbine and twin rotors are compared from three different aspects, including blade forces, power output efficiency and wake flow field. The results showed that the cyclic variations tendency of blade force coefficients of twin rotors is close to that of the stand-alone turbine. The average power output efficiency of the twin-rotors system is higher than that of the stand-alone turbine. The interactions between the turbines increase the power output of the twin turbine system as whole in a wide relative distance range. However, smaller relative distance between the twin rotors does not mean a bigger power output efficiency of such a system. The power out efficiency of such a system would decrease when the relative distance between the twin rotors exceeds the critical point. The power output of the twin rotors reaches the peak value when the ratio between the two main axis distance and diameter of the turbine is around 9/4. This research can provide a reference for the design and development of larger tidal power stations.

scholarly journals Numerical simulation of foil with leading-edge tubercle for vertical-axis tidal-current turbine

2020 ◽  
Vol 14 (3) ◽  
pp. 6982-6992
Author(s):  
I Ketut Aria Pria Utama ◽  
Dendy Satrio ◽  
Mukhtasor Mukhtasor ◽  
Mehmet Atlar ◽  
Weichao Shi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Tidal Current ◽  
Leading Edge ◽  
Vertical Axis ◽  
Simulation Method ◽  
Coefficient Of Performance ◽  
Simulation Results ◽  
Vertical Axis Turbine ◽  
Tidal Current Turbine ◽  
Current Turbine

The main disadvantage of the vertical-axis turbine is its low coefficient of performance. The purpose of this work was to propose a method to improve this performance by investigating the hydrodynamic forces and the flow-field of a foil that was modified with a sinusoidal leading-edge tubercle. NACA 63(4)021 was chosen as the original foil since it has a symmetrical profile that is suitable for use on a vertical-axis tidal-current turbine. The study was conducted using a numerical simulation method with ANSYS-CFX Computational Fluid Dynamics (CFD) code to solve the incompressible Reynolds-Averaged Navier-Stokes (RANS) equations. Firstly, the simulation results of the original foil were validated with available experimental data. Secondly, the modified foils, with three configurations of tubercles, were modelled. From the simulation results, the tubercle foils, when compared with the original foil, had similar lift performances at low Angles of Attack (0-8 degrees of AoA), lower lift performances at medium AoA (8-19 degrees) and higher lift performances at high AoA (19-32 degrees). A tubercle foil with Height/Chord (H/C) of 0.05 can maintain the static stall condition until 32 degrees. Therefore, a vertical-axis turbine with tubercle-blades provides an opportunity to increase its performance by extending the operational range for extracting energy in the dynamic stall condition.

CFD Study of 2D Model of Diffuser for Harnessing Tidal Energy

2012 ◽  
Vol 482-484 ◽  
pp. 2270-2274 ◽  
Author(s):  
Nasir Mehmood ◽  
Zhang Liang ◽  
Jawad Khan
Keyword(s):  
Fluid Flow ◽  
Power Output ◽  
Tidal Current ◽  
Experimental Results ◽  
Time Investment ◽  
Tidal Turbines ◽  
Simulation Results ◽  
Tidal Current Turbine ◽  
Current Turbine ◽  
2D Model

Diffuser augmented tidal turbines are getting enormous attention due to their immense potential to increase the generated power output. Researchers around the globe are investing considerable time and financial resources in this domain. Limited research results are available for diffuser augmented tidal turbines due to their emerging nature, large and costly research and development setup, startup cost and proprietary issues. Turbine enclosed in a diffuser is based on the principle that the generated power output by a tidal turbine is directly proportional to the cube of velocity of incoming fluid flow. Thus, even a minor increase in velocity considerably increases the generated power output. The diffuser helps accelerate the incoming fluid flow. Hence, the efficiency of the turbine is significantly increased by using a diffuser. It is challenging to accelerate the incoming flow by using a diffuser due to its shape, geometry and fabrication limitations. The diffuser design requires great deal of innovation and time investment. The purpose of this paper is to present the study of 2D model of diffuser for tidal current turbine. The study involves developing a 2D CFD model of diffuser, acquiring simulation results and comparison with experimental results. The mesh is generated in ICEM followed by simulation in CFX. The simulation results are compared to experimental results and found in reasonable agreement. The research is essential to utilize CFD tools for diffuser design used for tidal current turbine.

scholarly journals Optimization on the Law of Variable-Pitch Vertical-Axis Tidal Current Turbine

2018 ◽  
Vol 153 ◽  
pp. 03002
Author(s):  
Kong Fankai ◽  
Wang Liying ◽  
Zhang Di
Keyword(s):  
Tidal Current ◽  
Kinematic Model ◽  
Reference Value ◽  
Vertical Axis ◽  
Hydrodynamic Performance ◽  
Variable Pitch ◽  
Moment Coefficient ◽  
Tidal Current Turbine ◽  
Further Development ◽  
Current Turbine

In order to improve the hydrodynamic performance of the vertical-axis variable-pitch current turbine, with analyzing on the existing design mentality of blade control mechanism, an optimized law of variable-pitch vertical-axis tidal current turbine was given in terms of the instantaneous moment coefficient of the blade. A method for solving the lift - drag coefficient of Blade by wind - hole test data is given. The optimized kinematic model has a significant reference value for the further development of vertical axis turbine model test.

Structural Dynamic Analysis of a Tidal Current Turbine Using MBDyn

2018 ◽  
Author(s):  
Jun Leng ◽  
Ye Li
Keyword(s):  
Tidal Current ◽  
Interaction Analysis ◽  
Vertical Axis ◽  
Internal Force ◽  
Mode Shapes ◽  
Structural Dynamic ◽  
Tidal Current Energy ◽  
Integrated Simulation ◽  
Tidal Current Turbine ◽  
Current Turbine

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.

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

2020 ◽  
Vol 210 ◽  
pp. 107320 ◽  
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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