An Innovative Vertical Axis Current Turbine Design for Low Current Speed

2014 ◽  
Vol 66 (2) ◽  
Author(s):  
Fatemeh Behrouzi ◽  
Adi Maimun ◽  
Mehdi Nakisa ◽  
Mohamad Hanafi ◽  
Jaswar Jaswar

This article presents the new innovative concept for optimal design of Vertical Axis Current Turbines (VACT) applicable in low current speed which is being increasingly used to harness kinetic energy of water and convert it into other useful forms of energy as a clean and renewable energy. Widespread commercial acceptability of these turbo machines depends upon their efficiency. This largely depends upon the geometric features of the hydro turbines such as operation of designed system, joints, number and shape of blades and etc. The concept of VACT was proposed to provide a solution for the case of low current force inflow to vertical axis turbines. VACT has four suitable blades with flexible hinge joint to guide the water in come to reduce the drag force, light shaft and arms with stiff metal to make rigid and strong structure. The current study discusses the components of VAC turbine, rigidity of structure, performance, executive concept, efficiency, material, gearbox, environmental impacts and prevention of water corrosion. The new proposed innovative concept of VACT has flexible hinge connection for changing the blades directions automatically to reduce hydrodynamic drag and increase the hydrodynamic pressure to rotate the main shaft and enhance the efficiency as well. Main shaft connected to epicyclical gearbox to provide the higher torque for maximum electric power generation.

Author(s):  
Jun Leng ◽  
Ye Li

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.


2018 ◽  
Vol 42 (4) ◽  
pp. 404-415
Author(s):  
H. Abu-Thuraia ◽  
C. Aygun ◽  
M. Paraschivoiu ◽  
M.A. Allard

Advances in wind power and tidal power have matured considerably to offer clean and sustainable energy alternatives. Nevertheless, distributed small-scale energy production from wind in urban areas has been disappointing because of very low efficiencies of the turbines. A novel wind turbine design — a seven-bladed Savonius vertical-axis wind turbine (VAWT) that is horizontally oriented inside a diffuser shroud and mounted on top of a building — has been shown to overcome the drawback of low efficiency. The objective this study was to analyze the performance of this novel wind turbine design for different wind directions and for different guide vanes placed at the entrance of the diffuser shroud. The flow field over the turbine and guide vanes was analyzed using computational fluid dynamics (CFD) on a 3D grid for multiple tip-speed ratios (TSRs). Four wind directions and three guide-vane angles were analyzed. The wind-direction analysis indicates that the power coefficient decreases to about half when the wind is oriented at 45° to the main axis of the turbine. The analysis of the guide vanes indicates a maximum power coefficient of 0.33 at a vane angle of 55°.


2020 ◽  
Vol 210 ◽  
pp. 107320 ◽  
Author(s):  
Wang Hua-Ming ◽  
Qu Xiao-Kun ◽  
Chen Lin ◽  
Tu Lu-Qiong ◽  
Wu Qiao-Rui

Author(s):  
Ali Bakhshandeh Rostami ◽  
Antonio Carlos Fernandes

The present paper explores experimentally the performance of two types of hinged plates which rotate about vertical axis when submitted to uniform current. A flat plate configuration and also a flapped plate (say, S shape) configuration have been investigated. The Vertical axis Auto rotation Current Turbine (VAACT) is one degree of freedom system (free to rotate in yaw direction). It is shown that a high efficiency for S shape type can be obtained of the order of 30 percent while flat blade type reaches approximately to 7 percent. Upper limit of tip speed ratio for flat blade type has been expanded approximately 0.9 whereas S shape approaches 1.3.


Author(s):  
Wojciech Litwin

Water lubricated bearings are often installed on new and modernized ships. The main reasons are: unit simplicity, no danger of pollution and low price. One of the main problems connected with this the bearings of this kind is defining maximum hydrodynamic film capacity. Due to very thin hydrodynamic film and significant bearing bush deformation, the EHL model should be used for calculations. Experimental research conducted in the past was carried out on a single bearing test rig [1, 2, 3]. Unfortunately that test rig has some disadvantages. Its flexible support gives possibility of shaft misalignment for instance in case of asymmetric hydrodynamic pressure film in the bearing. The new test rig, presented in this paper gives wide research possibilities and working conditions are very similar to those on a real ship.


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