• Journal of Advanced Marine Engineering and Technology
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• v.37 no.4
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• pp.344-350
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• 2013

The purpose of this study is to examine the structural stability of a low speed 200 W class gyromill type vertical axis wind turbine system. For the analysis, a commercial code is adopted. The pressure distribution on the rotor blade surface is examined in detail. In order to perform unidirectional FSI(Fluid-Structure Interaction) analysis, the pressure resulted from CFD analysis has been mapped on the surface of wind turbine as load condition. The rotational speed and gravitational force of wind turbine are also considered. The results of FSI analysis show that the wind turbine reveals an enough structural margin. The maximum structural displacement occurs at trailing edge of blade and the maximum stress occurs at the strut.

• The KSFM Journal of Fluid Machinery
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• v.17 no.6
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• pp.64-68
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• 2014

This paper is intended to provide experimental data for the design of the small VAWT(vertical axis wind turbine). Three types(lift, drag, and hybrid) of the blade of VAWT are tested with digital wind tunnel in this study. From the test, the relation of power coefficient and tip speed ratio for the blades are evaluated and compared each other depending on the blade type. Especially, the characteristics of hybrid blade which is shown to be expanded in the market without any logical data is proposed in the relation of power coefficient and tip speed ratio. It is shown that the hybrid blade can be used to make higher starting torque with trade off of degradation of power coefficient.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.4
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• pp.330-335
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• 2016

In this study, aerodynamic characteristics of the blades of a helical-type vertical axis wind turbine(VAWT) have been investigated. For this purpose, a 100-W helical-type vertical axis wind turbine was designed using a design formulae, and a 3D computational fluid dynamics analysis was performed considering wind tunnel test conditions. Through the results of the analysis, the aerodynamic power output and flow characteristics of a helical blade were confirmed. In order to validate the aerodynamic power output obtained through the analysis, a wind tunnel test was performed by using a full-scale helical-type vertical axis wind turbine. The 3D analysis technique was validated by comparing its results with those obtained from the wind tunnel test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.8
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• pp.758-765
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• 2011

Recently, the wind energy has been widely used as a renewable energy resource due to lack and environmental issues of the mostly used fossil fuel. This work is to develop a 500W class blade design of vertical axis wind turbine system which will be applicable to relatively low speed region like Korea and for the domestic use. For this wind turbine a high efficiency and low noise turbine blade was designed with the proposing aerodynamic design procedure, and a light composite structure blade. Structural analyses were performed using the Finite Element Method and fatigue life of the designed blade is estimated. Finally, in order to check its performance, the manufactured blade was tested by using truck and the results of test was good with respect to its analysis result.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.2
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• pp.163-169
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• 2013

In order to make the vertical-axis cross flow wind turbine commercially feasible, a guide vane is adopted and the effect of the guide vane shape is examined in order to improve the wind turbine performance. CFD analysis on the performance and internal flow of the turbine is carried out for the wind turbine model. The result shows that when the guide nozzle is installed, almost over two times of power coefficient are achieved in comparison with the case of no guide nozzle installation. The guide nozzle acts as a role of suppressing the flow resistance at the blade passage, which is found when the guide nozzle is installed. Moreover, in this study, two kinds of the guide vane with a straight type and a curved type are adopted and compared. The curved guide vane nozzle produces higher power coefficient in comparison with that of straight guide vane nozzle.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.179.2-179.2
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• 2010

In this study, we have constructed the method of design about H-Darrieus wind turbine, a kind of VAWT(vertical axis wind turbine). The NACA 0012 airfoil is chosen for the blade, and DMS(double multiple streamtube) theory is used for the analysis. The flow field is computed with numerical solution of rotating Navier-Stokes equations. From the result of experimental data of power coefficient curves, the validity of the present research is checked. Through the non-dimensional parameter analysis for the wind turbine design, we estimated the efficiency of wind turbine with the resultant Cp's, with which an efficient design of VAWT is achieved, and aerodynamic characteristics are presented systematically.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.366-368
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• 2007

Mr. Hur has developed the 7500KW permanent magnet synchronous generator. The 7500KW generator has dual blade system with vertical axis type generation module. The 7500KW generator will generating that it is too expensive and construction payment. The advantages of dual blade system are cheap in generation with better efficiency, and safety compact structure. But also this system has the expensive slide ring for to distribute electrical power.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.602-606
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• 2011

In this study, operational vibration experiment and analysis have been conducted for the 4-blade small vertical-axis wind turbine (VAWT) including the effect of tower elastic behavior. Computational structural dynamics analysis method is applied to obtain Campbell diagram for the VAWT with elastic tower. An open type wind-tunnel is used to change and keep the wind velocity during the ground test. Equivalent reduced elastic tower is supported to the VAWT so that the elastic stiffness effect of the tower can be reflected to the present vibration experiment. Various excitation sources with aerodynamic forces are considered and the dominant operating vibration phenomena are physically investigated in detail.

• Journal of the Korean Society of Visualization
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• v.13 no.1
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• pp.15-20
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• 2015

Sensitivity studies of blade angle and twisted angle are numerically investigated to optimize the Savonius blade. As blade angle increases, the contact area between blade and wind decreases, showing the suppression of the vortex generation near blade. Compared to the blade angle of 0 degree, the blade angle of 20 degree shows about 2.6% increment of power efficiency. Based on the blade angle of 20 degree, sensitivity studies of the twisted angle are performed. The result indicates that the adjustment of the twisted angle causes the torque of blade to increase. Optimized blade can suppress the formation of the vortex structure in rear region. Also, wind flows without disturbance of vortex when passing through the optimized blade. The 1kw vertical wind turbine system with optimized blade can generate 4442.2kWh per year and have 53% capacity factor.

• Wind and Structures
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• v.17 no.6
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• pp.647-670
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• 2013

The paper presents a numerical approach to study of fluid flow characteristics and to predict performance of wind turbines. The numerical model is based on Finite-volume method (FVM) discretization of unsteady Reynolds-averaged Navier-Stokes (URANS) equations. The movement of turbine blades is modeled using moving mesh technique. The turbulence is modeled using commonly used turbulence models: Renormalization Group (RNG) k-${\varepsilon}$ turbulence model and the standard k-${\varepsilon}$ and k-${\omega}$ turbulence models. The model is validated with the experimental data over a large range of tip-speed to wind ratio (TSR) and blade pitch angles. In order to demonstrate the use of numerical method as a tool for designing wind turbines, two dimensional (2-D) and three-dimensional (3-D) simulations are carried out to study the flow through a small scale Darrieus type H-rotor Vertical Axis Wind Turbine (VAWT). The flows predictions are used to determine the performance of the turbine. The turbine consists of 3-symmetrical NACA0022 blades. A number of simulations are performed for a range of approaching angles and wind speeds. This numerical study highlights the concerns with the self-starting capabilities of the present VAWT turbine. However results also indicate that self-starting capabilities of the turbine can be increased when the mounted angle of attack of the blades is increased. The 2-D simulations using the presented model can successfully be used at preliminary stage of turbine design to compare performance of the turbine for different design and operating parameters, whereas 3-D studies are preferred for the final design.